The present invention relates to ionic silicone hydrogels displaying improved biocompatibility. More specifically, the present invention relates to a polymer formed from reactive components comprising at least one hydrophilic monomer, at least two hydroxyl substituted silicone containing components having different silicone contents, and at least one acyclic polyamide. The silicone hydrogels of the present invention display excellent physical, mechanical, and biological properties, making them suitable for ophthalmic applications such as contact lens materials.
It is well known that contact lenses can be used to improve vision. Various contact lenses have been commercially produced for many years. Hydrogel contact lenses are formed from hydrophilic polymers and copolymers containing repeating units such as 2-hydroxyethyl methylacrylate (HEMA). Of these, contact lenses formed from copolymers of HEMA and methacrylic acid, are among the most comfortable, and have the lowest rate of adverse events. Contact lenses formed from copolymers of HEMA and MAA, such ACUVUE®2 brand contact lenses, display substantial amounts of lysozyme uptake (greater than 500 µg) and retain a majority of the uptaken proteins in their native state. However, hydrogel contact lenses generally have oxygen permeabilities that are less than about 30.
Contact lenses made from silicone hydrogels have been disclosed. These silicone hydrogel lenses have oxygen permeabilities greater than about 60, and many provide reduced levels of hypoxia compared to conventional hydrogel contact lenses. Silicone hydrogel lenses may be exposed to extended periods of wear such as for several days in a row, for example, up to about 30 days.
The invention is defined by the claims. Silicone hydrogels disclosed herein exhibit improved biocompatibility with regards to interactions and absorption of tear film components as well as interactions and absorption of preservatives used for disinfecting contact lenses made from such silicone hydrogels. The lack of protein, lipid, or other biological deposits on the surface of contact lenses may limit, reduce, or eliminate any immunological responses or microbial fouling.
For reusable wear modalities, in which contact lenses are disinfected with multipurpose cleaning solutions between uses, another important characteristic of biocompatibility is low absorption of preservatives which may be released into the ocular environment upon subsequent wear.
The silicone hydrogels of the present invention exhibit many of these biocompatible properties, while achieving an excellent balance of physical and mechanical properties.
The present invention provides a silicone hydrogel formed from a reactive monomer mixture comprising:
- a. between about 1 and about 15 wt% at least one polyamide;
- b. at least one first mono-functional, hydroxyl substituted poly(disubstituted siloxane) having 4 to 8 siloxane repeating units;
- c. at least one second hydroxyl substituted poly(disubstituted siloxane) selected from the group consisting of mono-functional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200 or 10-100 siloxane repeating units and multifunctional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200, or 10 to 100 siloxane repeating units, and mixtures thereof;
- d. about 5 to about 30 wt% at least one additional hydrophilic monomer;
- e. wherein the first hydroxyl substituted, linear poly(disubstituted siloxane) and the second mono-functional hydroxyl substituted, linear poly(disubstituted siloxane) are present in concentrations to provide a ratio of wt% of all first hydroxyl substituted, linear poly(disubstituted siloxane) to wt% of all one second hydroxyl substituted poly(disubstituted siloxane)s of 0.4-1.3, or 0.4-1.0.
The present invention provides a silicone hydrogel formed from a reactive monomer mixture comprising:
- i. between about 1 and about 15 wt% at least one polyamide;
- ii. at least one hydroxyl silicone-containing monomer;
- iii. at least one hydroxyl substituted poly(disubstituted siloxane) selected from the group consisting of poly(disubstituted siloxane) having 4 to 8 siloxane repeating units, monofunctional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200 or 10-100 siloxane repeating units and multifunctional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200, or 10 to 100 siloxane repeating units, and mixtures thereof;
- iv. about 5 to about 20 wt% at least one additional hydrophilic monomer;
- v. wherein the first hydroxyl substituted, linear poly(disubstituted siloxane) and the second monofunctional hydroxyl substituted, linear poly(disubstituted siloxane) are present in concentrations to provide a ratio of wt% of all first hydroxyl substituted, linear poly(disubstituted siloxane) to wt% of all one second hydroxyl substituted poly(disubstituted siloxane)s of 0.4-1.3, or 0.4-1.0.
The present invention also provides biomedical devices, ophthalmic devices and contact lenses comprising the silicone hydrogels described herein.
These and other embodiments of the invention will become apparent from the following description, which are illustrative of the invention. The description does not limit the scope of the invention, which is defined by the claims and equivalents thereof. Variations and modifications of the invention may be effected without departing from the scope of the novel contents of the disclosure.
Provided are silicone hydrogels formed from a reactive monomer mixture comprising: a first hydroxyl substituted, linear poly(disubstituted siloxane) having 4 to 8 siloxane repeating units; a second hydroxyl substituted, linear poly(disubstituted siloxane) selected from the group consisting of a monofunctional hydroxyl substituted, linear poly(disubstituted siloxane) having 10 to 20 siloxane repeating units and a multifunctional hydroxyl substituted, linear poly(disubstituted siloxane) having 10 to 200, or 10 to 100 siloxane repeating units; and at least one polyamide; wherein the ratio of the first hydroxyl substituted linear poly(disubstituted siloxane) to the second hydroxyl substituted, linear poly(disubstituted siloxane) is in a range of 0.4 to 1.2, or 0.4 to 1.0.
With respect to the terms used in this disclosure, the following definitions are provided. The polymer definitions are consistent with those disclosed in the Compendium of Polymer Terminology and Nomenclature, IUPAC Recommendations 2008, edited by: Richard G. Jones, Jaroslav Kahovec, Robert Stepto, Edward S. Wilks, Michael Hess, Tatsuki Kitayama, and W. Val Metanomski.
As used herein, the term "about" refers to a range of +/-5% of the number that is being modified. For example, the phrase "about 10" would include both 9.5 and 10.5.
The term "(meth)" designates optional methyl substitution. Thus, a term such as "(meth)acrylate" denotes both methacrylate and acrylate radicals.
Wherever chemical structures are given, it should be appreciated that alternatives disclosed for the substituents on the structure may be combined in any combination. Thus, if a structure contained substituents R* and R**, each of which contained three lists of potential groups, 9 combinations are disclosed. The same applies for combinations of properties.
When a subscript, such as "n" in the generic formula [***]n, is used to depict the number of repeating units in a polymer's chemical formula, the formula should be interpreted to represent the number average molecular weight of the macromolecule.
A "macromolecule" is an organic compound having a molecular weight of greater than 1500, and may be reactive or non-reactive.
A "polymer" is a macromolecule of repeating chemical units linked together into a chain or network structure and is composed of repeating units derived from the monomers and macromers included in the reactive mixture.
A "homopolymer" is a polymer made from one monomer or macromer; a "copolymer" is a polymer made from two or more monomers, macromers or a combination thereof; a "terpolymer" is a polymer made from three monomers, macromers or a combination thereof. A "block copolymer" is composed of compositionally different blocks or segments. Diblock copolymers have two blocks. Triblock copolymers have three blocks. "Comb or graft copolymers" are made from at least one macromer.
A "repeating unit" or "repeating chemical unit" is the smallest repeating group of atoms in a polymer that result from the polymerization of monomers and macromers.
"Biomedical device" is any article that is designed to be used while either in or on mammalian tissues or fluid, and preferably in or on human tissue or fluids. Examples of these devices include but are not limited to wound dressings, sealants, tissue fillers, drug delivery systems, coatings, adhesion prevention barriers, catheters, implants, stents, sutures, and ophthalmic devices such as intraocular lenses and contact lenses. The biomedical devices may be ophthalmic devices, such as contact lenses, including contact lenses made from silicone hydrogels.
"Individual" includes humans and vertebrates.
"Ocular surface" includes the surface and glandular epithelia of the cornea, conjunctiva, lacrimal gland, accessory lacrimal glands, nasolacrimal duct and meibomian gland, and their apical and basal matrices, puncta and adjacent or related structures, including eyelids linked as a functional system by both continuity of epithelia, by innervation, and the endocrine and immune systems.
"Ophthalmic device" refers to any device which resides in or on the eye or any part of the eye, including the ocular surface. These devices can provide optical correction, cosmetic enhancement, vision enhancement, therapeutic benefit (for example as bandages) or delivery of active components such as pharmaceutical and nutraceutical components, or a combination of any of the foregoing. Examples of ophthalmic devices include, but are not limited to, lenses and optical and ocular inserts, including, but not limited to punctal plugs and the like. The "term lens" includes soft contact lenses, hard contact lenses, hybrid contact lenses, intraocular lenses, and overlay lenses. The ophthalmic device may comprise a contact lens.
"Contact lens" refers to an ophthalmic device that can be placed on the cornea of an individual's eye. The contact lens may provide corrective, cosmetic, therapeutic benefit, including wound healing, delivery of active components such as drugs or neutraceuticals, diagnostic evaluation or monitoring, or UV blocking and visible light or glare reduction, or a combination thereof. A contact lens can be of any appropriate material known in the art, and can be a soft lens, a hard lens, or a hybrid lens containing at least two distinct portions with different properties, such as modulus, water content, light absorbing characteristics or combinations thereof.
The biomedical devices, ophthalmic devices, and lenses of the present invention may be comprised of silicone hydrogels. These silicone hydrogels typically contain a silicone component and/or hydrophobic and hydrophilic monomers that are covalently bound to one another in the cured device.
"Silicone hydrogel contact lens" refers to a contact lens comprising at least one silicone hydrogel material. Silicone hydrogel contact lenses generally have increased oxygen permeability compared to conventional hydrogels. Silicone hydrogel contact lenses use both their water and polymer content to transmit oxygen to the eye.
A "polymeric network" is cross-linked macromolecule that can swell but cannot dissolve in solvents, because the polymeric network is essentially one macromolecule. "Hydrogel" or "hydrogel material" refers to a polymeric network that contains water in an equilibrium state. Hydrogels generally contain at least about 10 wt.% water, or at least about 15 wt.% water
" Conventional hydrogels" refer to polymeric networks made from monomers without any siloxy, siloxane or carbosiloxane groups. Conventional hydrogels are prepared from monomeric mixtures predominantly containing hydrophilic monomers, such as 2-hydroxyethyl methacrylate ("HEMA"), N-vinyl pyrrolidone ("NVP"), N, N-dimethylacrylamide ("DMA"), or vinyl acetate.
"Silicone hydrogel" refers to a hydrogel obtained by copolymerization of at least one silicone-containing component with at least one hydrophilic component. Hydrophilic components may also include non-reactive polymers. Each of the silicone-containing components and the hydrophilic components may be a monomer, macromer or combination thereof. A silicone-containing component contains at least one siloxane or carbosiloxane group. Examples of commercially available silicone hydrogels include balafilcon, acquafilcon, lotrafilcon, comfilcon, delefilcon, enfilcon, fanfilcon, foimofilcon, galyfilcon, senofilcon, narafilcon, falcon II, asmofilcon A, samfilcon, riofilcon, stenficlon, somofilcon, as well as silicone hydrogels as prepared in
"Silicone-containing component" refers to a monomer, macromer, prepolymer, cross-linker, initiator, additive, or polymer that contains at least one silicon-oxygen bond, in the form of siloxane [-Si-O-Si] group or carbosiloxane group. Examples of silicone-containing components include, but are not limited to, silicone macromers, prepolymers, and monomers. Examples of silicone macromers include, but are not limited to, polydimethylsiloxane methacrylated with pendant hydrophilic groups. Examples of silicone-containing components which are useful in this invention may be found in
"Reactive mixture" and "reactive monomer mixture" refer to the mixture of components (both reactive and non-reactive) which are mixed together and when subjected to polymerization conditions, form the silicone hydrogels and lenses of the present invention. The reactive mixture comprises reactive components such as monomers, macromers, prepolymers, cross-linkers, initiators, diluents, and additional components such as wetting agents, release agents, dyes, light absorbing compounds such as UV absorbers, pigments, dyes and photochromic compounds, any of which may be reactive or non-reactive but are capable of being retained within the resulting biomedical device, as well as active components such as pharmaceutical and nutraceutical compounds, and any diluents. It will be appreciated that a wide range of additives may be added based upon the biomedical device which is made, and its intended use. Concentrations of components of the reactive mixture are given in weight % of all components in the reaction mixture, excluding diluent. When diluents are used their concentrations are given as weight % based upon the amount of all components in the reaction mixture and the diluent.
"Monomer" is a molecule having non-repeating functional groups, which can undergo chain growth polymerization, and in particular, free radical polymerization. Some monomers have di-functional impurities that can act as cross-linking agents. "Macromers" are linear or branched polymers having a repeating structure and at least one reactive group that can undergo chain growth polymerization. Monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane (molecular weight = 500-1500 g/mol) (mPDMS) and mono-(2-hydroxy-3-methacryloxypropyl)-propyl ether terminated mono-n-butyl terminated polydimethylsiloxane (molecular weight = 500-1500 g/mol) (OH-mPDMS) are referred to as macromers. Typically, the chemical structure of the macromer is different than the chemical structure of the target macromolecule, that is, the repeating unit of the macromer's pendent group is different than the repeating unit of the target macromolecule or its mainchain.
"Reactive components" are the components in the reactive mixture which become part of the structure of the polymeric network of the resulting silicone hydrogel, by covalent bonding, hydrogen bonding or the formation of an interpenetrating network. Diluents and processing aids which do not become part of the structure of the polymer are not reactive components.
"Polymerizable" means that the compound comprises at least one reactive group which can undergo chain growth polymerization, such as free radical polymerization. Examples of reactive groups include the monovalent reactive groups listed below. "Non-polymerizable" means that the compound does not comprises such a polymerizable group.
"Monovalent reactive groups" are groups that can undergo chain growth polymerization, such as free radical and/or cationic polymerization. Non-limiting examples of free radical reactive groups include (meth)acrylates, styrenes, vinyl ethers, (meth)acrylamides, N-vinyllactams, N-vinylamides, O-vinylcarbamates, O-vinylcarbonates, and other vinyl groups. In one embodiment, the free radical reactive groups comprise (meth)acrylate, (meth)acrylamide, N-vinyl lactam, N-vinylamide, and styryl functional groups, or (meth)acrylates, (meth)acrylamides, and mixtures of any of the foregoing.
Examples of the foregoing include substituted or unsubstituted C1-6alkyl(meth)acrylates, C1-6alkyl(meth)acrylamides, C2-12alkenyls, C2-12alkenylphenyls, C2-12alkenylnaphthyls, C2-6alkenylphenylC1-6alkyls, where suitable substituents on said C1-6 alkyls include ethers, hydroxyls, carboxyls, halogens and combinations thereof.
Other polymerization routes such as living free radical and ionic polymerization can also be employed. The device-forming monomers may form hydrogel copolymers. For hydrogels, the reactive mixture will typically include at least one hydrophilic monomer.
Hydrophilic components are those which yield a clear single phase when mixed with deionized water at 25°C at a concentration of 10 wt.%.
"Interpenetrating polymer networks" or "IPNs" are polymers comprising two or more polymeric networks which are at least partially interlaced on a molecular scale, but not covalently bonded to each other and cannot be separated unless chemical bonds are broken.
"Semi-interpenetrating polymer networks" or "semi-IPNs" are polymer comprising one or more polymer network(s) and one or more linear or branched polymer(s) characterized by the penetration on a molecular scale of at least one of the networks by at least some of the linear or branched chains.
A "cross-linking agent" is a di-functional or multi-functional component which can undergo free radical polymerization at two or more locations on the molecule, thereby creating branch points and a polymeric network. Common examples are ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, methylene bisacrylamide, triallyl cyanurate, and the like.
The phrase "without a surface treatment" means that the exterior surfaces of the devices (e.g. silicone hydrogels, contact lenses) of the present invention are not separately treated to improve the wettability of the device. Treatments which may be foregone include, plasma treatments, grafting, coating, and the like. Coatings, however, which provide properties other than improved wettability, such as, but not limited to antimicrobial coatings and the application of color or other cosmetic enhancement may be applied to devices of the present invention.
Non-SI units disclosed in this description are convertible as following:
- 1 inch = 25.4 mm
- 1 psi = 6894.76 Pa
- 1 lb = 453.592 g.
A silicone hydrogel may be formed from a reactive monomer mixture comprising at least one anionic monomer, at least one first mono-functional hydroxyl-substituted poly(disubstituted siloxane), at least one second mono-functional hydroxyl-substituted poly(disubstituted siloxane), at least one hydroxyl functional monomer, and at least one acylic polyamide.
The reactive monomer mixture includes at least one polyamide. As used herein, the term "polyamide" refers to polymers and copolymers comprising repeating units containing amide groups. The polyamide may comprise cyclic amide groups, acyclic amide groups and combinations thereof, and may be any polyamide known to those of skill in the art.
Acyclic polyamides comprise pendant acyclic amide groups and are capable of association with hydroxyl groups. Cyclic polyamides comprise cyclic amide groups and are capable of association with hydroxyl groups.
Examples of suitable acyclic polyamides include polymers and copolymers comprising repeating units of Formula I or Formula II:
- wherein X is a direct bond, -(CO)-, or -(CO)-NHRe-, wherein Re is a C1 to C3 alkyl group; Ra is selected from H, straight or branched, substituted or unsubstituted C1 to C4 alkyl groups; Rb is selected from H, straight or branched, substituted or unsubstituted C1 to C4 alkyl groups, amino groups having up to two carbon atoms, amide groups having up to four carbon atoms, and alkoxy groups having up to two carbon groups; Rc is selected from H, straight or branched, substituted or unsubstituted C1 to C4 alkyl groups, or methyl, ethoxy, hydroxyethyl, and hydroxymethyl; Rd is selected from H, straight or branched, substituted or unsubstituted C1 to C4 alkyl groups; or methyl, ethoxy, hydroxyethyl, and hydroxymethyl wherein the number of carbon atoms in Ra and Rb taken together is 8 or less, including 7, 6, 5, 4, 3, or less, and wherein the number of carbon atoms in Rc and Rd taken together is 8 or less, including 7, 6, 5, 4, 3, or less. The number of carbon atoms in Ra and Rb taken together may be 6 or less or 4 or less. The number of carbon atoms in Rc and Rd taken together may be 6 or less. As used herein substituted alkyl groups include alkyl groups substituted with an amine, amide, ether, hydroxyl, carbonyl, carboxy groups or combinations thereof.
- Ra and Rb can be independently selected from H, substituted or unsubstituted C1 to C2 alkyl groups. X may be a direct bond, and Ra and Rb may be independently selected from H, substituted or unsubstituted C1 to C2 alkyl groups.
- Rc and Rd can be independently selected from H, substituted or unsubstituted C1 to C2 alkyl groups, methyl, ethoxy, hydroxyethyl, and hydroxymethyl.
The acyclic polyamides of the present invention may comprise a majority of the repeating unit of Formula I or Formula II, or the acyclic polyamides can comprise at least about 50 mole % of the repeating unit of Formula I or Formula II, including at least about 70 mole %, and at least 80 mole %.
Specific examples of repeating units of Formula I and Formula II include repeating units derived from N-vinyl-N-methylacetamide, N-vinylacetamide, N-vinyl-N-methylpropionamide, N-vinyl-N-methyl-2-methylpropionamide, N-vinyl-2-methyl-propionamide, N-vinyl-N,N'-dimethylurea, N, N-dimethylacrylamide, methacrylamide, and acyclic amides of Formulae IIIa and IIIb:
The acyclic polyamides may also be copolymers comprising both acyclic and cyclic amide repeating units. Examples of suitable cyclic amides that can be used to form the acyclic polyamides include α-lactam, β-lactam, γ-lactam, δ-lactam, and ε-lactam. Examples of suitable cyclic amides include repeating units of Formula IV:
When X is a direct bond, f may be 2. In such instances, the cyclic polyamide may be poly(vinyl pyrrolidone) (PVP).
Specific examples of repeating units of Formula IV include repeating units derived from N-vinylpyrrolidone (NVP).
Additional repeating units may be formed from monomers selected from N-vinyl amides, acrylamides, hydroxyalkyl(meth)acrylates, alkyl(meth)acrylates and siloxane substituted acrylates or methacrylates. Specific examples of monomers which may be used to form the additional repeating units of the acyclic polyamides include as N-vinylpyrrolidone, N,N-dimethylacrylamide (DMA), 2-hydroxyethylmethacrylate, vinyl acetate, acrylonitrile, hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, methyl methacrylate and butyl methacrylate, hydroxybutyl methacrylate, GMMA, PEGS, , and the like and mixtures thereof. Ionic monomers may also be included. Examples of ionic monomers include acrylic acid, methacrylic acid, 2-methacryloyloxyethyl phosphorylcholine, 3-(dimethyl(4-vinylbenzyl)ammonio)propane-1-sulfonate (DMVBAPS), 3-((3-acrylamidopropyl)dimethylammonio)propane-1-sulfonate (AMPDAPS), 3-((3-methacrylamidopropyl)dimethylammonio)propane-1-sulfonate (MAMPDAPS), 3-((3-(acryloyloxy)propyl)dimethylammonio)propane-1-sulfonate (APDAPS), methacryloyloxy)propyl)dimethylammonio)propane-1-sulfonate (MAPDAPS), ), 1-propanaminium,N-(2-carboxyethyl)-N,N-dimethyl-3-[(1-oxo-2-propen-1-yl)amino]-, inner salt (CBT, carboxybetaine;
The at least one acylic polyamide may be selected from the group consisting of polyvinylmethylacrylamide (PVMA), polyvinylacetamide (PNVA), polydimethylacrylamide (PDMA), polyacrylamide and poly[N-vinyl N-alkyl acetamide] wherein the N-alkyl group is selected from the group consisting of linear and branched alkyl groups containing between one (C1) and five (C5) carbon atoms.
The reactive monomer mixture may comprise both an acyclic polyamide and a cyclic polyamide or copolymers thereof. The acyclic polyamide can be any of those acyclic polyamides described herein or copolymers thereof, and the cyclic polyamide can be formed from any combination of the repeating units of Formula IV, either alone or with other repeating units. Examples of cyclic polyamides include PVP and PVP copolymers. Other polymeric internal wetting agents, such as poly(hydroxyethyl(meth)acrylamide), may also be included.
Without intending to be bound by theory, the polyamide functions as an internal wetting agent in the resulting silicone hydrogel. The polyamides of the present invention may be non-polymerizable, and in this case is incorporated into the silicone hydrogels as a semi-interpenetrating network. The non-polymerizable polyamide is "entrapped", or physically retained within a hydrogel matrix. Alternatively, the polyamides of the present invention may be polymerizable, for example as polyamide macromers, which are covalently incorporated into the silicone hydrogels. Reactive polyamides may be functionalized to contain at least one monovalent reactive group.
When the polyamides are incorporated into the reactive monomer mixture they may have a weight average molecular weight of at least about 100,000 Daltons; greater than about 150,000; between about 150,000 to about 2,000,000 Daltons, between about 300,000 to about 1,800,000 Daltons.
The polyamides may also comprise at least one reactive group. For polyamides having molecular weights of 10,000 Daltons, a single reactive group may be included. For polyamides having molecular weights greater than about 10,000, greater than about 30,000, or greater than about 100,000 Daltons, more than one reactive group may be included. Mixtures of reactive and non-reactive polyamides may also be used.
The polyamides may be incorporated into the hydrogel by a variety of methods. For example, the polyamide may be added to the reaction mixture such that the hydrogel polymerizes "around" the polyamide, forming a semi-interpenetrating network.
The total amount of all polyamides in the reactive mixture may be from about 1 to about 15 wt%, between about 3 and about 15 wt%, or between about 3 and about 12 wt%, based upon the total weight of the reactive components of the reactive monomer mixture.
The reactive monomer mixture also includes a mixture of hydroxyl-containing silicone components of different molecular weights or different compositions. The first hydroxyl-containing silicone component may be selected from hydroxyl-containing silicone monomers, and hydroxyl containing polydisubstituted siloxanes having at least 4 polydisubstituted siloxane repeating units or 4-8 polydisubstituted siloxane repeating units; and at least one monovalent reactive group. When the first hydroxyl-containing silicone component is a hydroxyl-containing silicone monomer, the second hydroxyl-containing silicone component may be selected from hydroxyl substituted poly(disubstituted siloxane) having 4 to 8 siloxane repeating units, monofunctional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200, 10-100 or 10-20 siloxane repeating units and multifunctional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200, or 10 to 100 siloxane repeating units, and mixtures thereof. When the first hydroxyl-containing silicone component is a hydroxyl-substituted poly(disubstituted siloxane) having 4 to 8 siloxane repeating units, the second hydroxyl-containing silicone component may be selected from monofuntional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200, 10-100 or 10-20 siloxane repeating units and multifunctional hydroxyl substituted poly(disubstituted siloxane)s having 10 to 200, or 10 to 100 siloxane repeating units, and mixtures thereof.
Hydroxyl-containing silicone components having 4 polydisubstituted siloxane repeating units in the siloxane chain are not a distribution and have four repeating units in each monomer. For all hydroxyl-containing silicone components having more than four polydisubstituted siloxane repeating units in the siloxane chain the number of repeating units is a distribution, with the peak of the distribution centered around the listed number of repeat units.
The elemental Si content of the hydroxyl containing silicone component is greater than about 20 weight percent, to about 38 weight percent of the total molecular weight of the hydroxyl containing silicone component.
Examples of hydroxyl-containing silicone monomers include propenoic acid-2-methyl-2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]-1-disiloxanyl]propoxy]propyl ester ("SiGMA"), and 2-hydroxy-3-methacryloxypropyloxypropyl-tris(trimethylsiloxy)silane, and compounds of Formula VI:
The hydroxyl-containing silicone components may be selected from monofunctional hydroxyl substituted, poly(disubstituted siloxane)s of Formula VII-1:
- wherein Z is selected from O, N, S or NCH2CH2O, when Z is O or S R2 is not present;
- R1 is independently H or methyl;
- R2 is H or is a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, amide, ether, and combinations thereof;
- R3 and R4 are independently a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, and which may be optionally substituted with amide, ether, and combinations thereof; R3 and R4 may be independently selected from methyl, ethyl or phenyl, or may be methyl;
- n is the number of siloxane units and is from 4 to 8 for the first monofunctional hydroxyl substituted poly(disubstituted siloxane) monomer (or, when the compound is present as a second hydroxyl substituted poly(disubstituted siloxane), n may be 10 to 200, or 10-100, or 10-50, or 10-20, or 12-18), and
- R5 is selected from straight or branched C1 to C8 alkyl groups, which may be optionally substituted with one or more hydroxyl, amide, ether, and combinations thereof. R5 may be straight or branched C4 alkyl, either of which may optionally be substituted with hydroxyl, or may be methyl.
The hydroxyl-containing silicone components may be selected from monofunctional hydroxyl substituted, poly(disubstituted siloxane)s of Formula VII-2:
- wherein Z is selected from O, N, S or NCH2CH2O, when Z is O or S R2 is not present;
- R1 is independently H or methyl;
- R2 is H or is a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, amide, ether, and combinations thereof;
- R3 and R4 are independently a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, and which may be optionally substituted with amide, ether, and combinations thereof; R3 and R4 may be independently selected from methyl, ethyl or phenyl, or may be methyl;
- n is the number of siloxane units and is from 10 to 200, or 10-100, or 10-50, or 10-20, or 12-18 for the second monofunctional hydroxyl substituted poly(disubstituted siloxane); and
- R5 is selected from straight or branched C1 to C8 alkyl groups, which may be optionally substituted with one or more hydroxyl, amide, ether, and combinations thereof. R5 may be straight or branched C4 alkyl, either of which may optionally be substituted with hydroxyl, or may be methyl.
Examples of monofunctional hydroxyl containing silicone components include mono-(2-hydroxy-3-methacryloxypropyl)-propyl ether terminated mono-n-butyl terminated polydimethylsiloxanes (OH-mPDMS) as shown in Formula VIIa wherein n is between 4 and 30, 4-8 or 10-20 or 4 to 15; and polydimethylsiloxanes having the chemical structures as shown in Formulae VIIb through VIIId, where n is between 4 and 30, 4 and 8 or 10 and 20; n1 and n2 are independently between 4 to 100; 4 to 50; 4 to 25; n3 is 1-50, 1-20, or 1-10; R5 is selected from straight or branched C1 to C8 alkyl groups, which may be optionally substituted with one or more hydroxyl, amide, ether, polyhydroxyl groups selected from straight or branched C1 to C8 groups having a formula of CfHg(OH)h wherein f=1-8 and g+h=2f+1 and cyclic C1 to C8 groups having a formula of CfHg(OH)h wherein f=1-8 and g+h=2f-1, and combinations thereof; or R5 may be selected from methyl, butyl or hydroxyl substituted C2-C5 alkyl, including hydroxyl ethyl, hydroxyl propyl, hydroxyl butyl, hydroxyl pentyl and 2,3-dihydroxypropyl; and polycarbosiloxanes of Formula IXa and IXb wherein "a" = 4-8 for the first hydroxyl-containing silicone component and "a" is between 4-100 for the second hydroxyl-containing silicone component, R1 and R5 are as defined above; wherein Z is selected from O, N, S or NCH2CH2O, when Z is O or S R2 is not present; R2 is independently selected from the group consisting of a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, and which may be optionally substituted with amide, ether, and combinations thereof; and R3 and R4 are independently a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, and which may be optionally substituted with amide, ether, and combinations thereof; R3 and R4 may be independently selected from methyl, ethyl or phenyl, or may be methyl.
The second hydroxyl-containing silicone component may be selected from the group consisting of a second monofunctional hydroxyl substituted, poly(disubstituted siloxane) of general Formula VI, or compounds of Formulae VIIa-IX having 10 to 200 siloxane repeating units and a multifunctional hydroxyl substituted, poly(disubstituted siloxane) of Formula X having 10 to 500, or 10 to 200, or 10 to 100 siloxane repeating units, and mixtures thereof:
- wherein in Formula X, Z is selected from O, N, S or NCH2CH2O; wherein R1 is independently a hydrogen atom or methyl group; for Z = O and S, R2 is not required;
- R2, R3, R4, R5, R6, R7 are independently selected from the group consisting of a hydrogen atom or any of the substituents defined for R8 through R11;
- R8, R9, R10, R11 are independently selected from the group consisting of a linear, branched, or cyclic alkyl group containing one to eight carbon atoms, any of which may be further substituted with at least one hydroxy group, amido, ether, amino, carboxyl, carbonyl groups and combinations; a linear or branched alkyleneoxy group, specifically ethyleneoxy groups, [CH2CH2O]p wherein p is between 1 and 200, or 1 and 100, or 1 and 50, or 1 and 25, or 1 and 20, optionally substituted with one or more hydroxyl, amino, amido, ether, carbonyl, carboxyl, and combinations thereof; a C1-C6 linear or branched fluoroalkyl groups optionally substituted with one or more hydroxyl, amino, amido, ether, carbonyl, carboxyl, and combinations thereof; a substituted or un-substituted aryl groups, specifically phenyl groups, wherein the substituents are selected from halogen, hydroxyl, alkoxy, alkylcarbonyl, carboxy, and linear or branched or cyclic alkyl groups which may be further substituted with halogen, hydroxyl, alkoxy, alkylcarbonyl, and carboxyl groups, and combinations thereof;
- a, b, c, x, y and z are independently between 0 and 100, between 0 and 50, between 0 and 20, between 0 and 10, or between 0 and 5, and may be ordered in any molecular sequence to make a wide range of substituted hydroxy-oxa-alkylene chains, and n is the number of siloxane repeating units and is from 10 to 500; 10 to 200; 10 to 100; 10 to 50; 10 to 20.
The weight ratio of the first mono-functional hydroxyl-substituted poly(disubstituted siloxane) to the second hydroxyl-substituted poly(disubstituted siloxane) is in a range of 0.1 to 2, or 0.1 to 1.
The hydroxyl-containing silicone components may comprise a mixture of a first mono-functional hydroxyl-substituted poly(disubstituted siloxane) of Formula VI, or VIIa-IX where n is from 4 to 8 and a second hydroxyl-substituted poly(disubstituted siloxane) selected from the group consisting of a mono-functional hydroxyl-substituted poly(disubstituted siloxane) of Formula VI or VIIa to IX, wherein n is from 10-200, 10-100 or 10-20 and a di-functional hydroxyl-substituted poly(disubstituted siloxane) of Formula XI
The hydroxyl-containing silicone components may comprise a mixture of a first mono-functional hydroxyl-substituted poly(disubstituted siloxane) of Formula VI, or VIIa-IX where n is from 4 to 8, a second hydroxyl-substituted poly(disubstituted siloxane) selected from the group consisting of a mono-functional hydroxyl-substituted poly(disubstituted siloxane) of Formula VI or VIIa to IX, wherein n is from 10-200, 10-100 or 10-20, and a di-functional hydroxyl-substituted poly(disubstituted siloxane) of Formula XI.
Examples of multifunctional hydroxyl containing silicones include α-(2-hydroxy-1-methacryloxypropyloxypropyl)-ω-butyl-decamethylpentasiloxane and those of Formula XII:
The ratio of the first hydroxyl-containing silicone component to any of the above described second hydroxyl substituted, poly(disubstituted siloxane) can be in a range of 0.2-1.3, 0.4-1.3, 0.4-1 and 0.6-1.
The hydroxyl-containing silicone components may be present in amounts between about 40-about 70wt%, or about 45-about 70wt%.
Additional silicone-containing compounds without hydroxyl functionality may also be included. Suitable examples include those of Formula XIII:
In Formula XIII, from one to three R1 may comprise monovalent reactive groups. Suitable monovalent alkyl and aryl groups include unsubstituted and substituted monovalent linear, branched or cyclic C1 to C16 alkyl groups, or unsubstituted monovalent C1 to C6 alkyl groups, such as substituted and unsubstituted methyl, ethyl, propyl, butyl, substituted or unsubstituted C6-C14 aryl groups, or a substituted or un-substituted C6 aryl group, wherein the substituents include amido, ether, amino, halo, hydroxyl, carboxyl, carbonyl groups; or a phenyl or benzyl group, combinations thereof and the like.
When one R1 is a monovalent reactive group, the additional silicone containing compounds may be selected from the polydisubstituted siloxane macromer of Formula XIVa or XIVb; the styryl polydisubstituted siloxane macromer of Formula XVa or XVb; or the carbosilane of Formula XVc:
When Z is O, non-limiting examples of polysiloxane macromers include monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxanes (mPDMS) as shown in Formula XVI wherein n is between 3 and 15; monomethacryloxypropyl terminated mono-n-alkyl terminated polydimethylsiloxanes, mono-n-alkyl terminated, polydimethyl, polyethylene glycol siloxanes as shown in Formula XVIIa and XVIIb wherein R1 is a proton or methyl group; wherein R5 may be C1-C4 alkyl or methyl or butyl; wherein n is 3-15; wherein n1 and n2 are between 4 to 100, 4 to 50, or 4 to 25, and n3 is 1-50, 1-20, or 1-10; and macromers having the chemical structures as shown in formulae XVIIIa through XXIb wherein R1 is a proton or methyl group; wherein n is between 4-100, 4 and 20, or between 3 and 15; wherein n1 and n2 are between 4 to 100, 4 to 50, or 4 to 25, and n3 is 1-50, 1-20, or 1-10; and R5 may be C1-C4 alkyl or methyl or butyl.
Examples of suitable mono(meth)acryloxyalkylpolydisubstituted siloxanes include mono(meth)acryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane, mono(meth)acryloxypropyl terminated mono-n-methyl terminated polydimethylsiloxane, mono(meth)acryloxypropyl terminated mono-n-butyl terminated polydiethylsiloxane, mono(meth)acryloxypropyl terminated mono-n-methyl terminated polydiethylsiloxane, mono(meth)acrylamidoalkylpolydialkylsiloxanes mono(meth)acryloxyalkyl terminated mono-alkyl polydiarylsiloxanes, and mixtures thereof.
In Formula XIII, when n is zero, one R1 may be a monovalent reactive group, and at least 3 R1 are selected from monovalent alkyl groups having 1 to 16, 1 to 6 or 1-4 carbon atoms. Non-limiting examples of silicone components include, 3-methacryloxypropyltris(trimethylsiloxy)silane (TRIS), 3-methacryloxypropyl-bis(trimethylsiloxy)methylsilane, and 3-methacryloxypropylpentamethyl disiloxane.
The number of siloxane repeating units, n, may also be 2 to 50, 3 to 25, or 3 to 15; wherein at least one terminal R1 comprises a monovalent reactive group and the remaining R1 are selected from monovalent alkyl groups having 1 to 16 carbon atoms, or from monovalent alkyl groups having 1 to 6 carbon atoms. Non-hydroxyl containing silicone compounds may also include those where n is 3 to 15, one terminal R1 comprises a monovalent reactive group, the other terminal R1 comprises a monovalent alkyl group having 1 to 6 carbon atoms and the remaining R1 comprise monovalent alkyl group having 1 to 3 carbon atoms. Non-limiting examples of silicone components include monomethacryloxypropyl n-butyl terminated polydimethylsiloxanes (Mn=800-1000), (mPDMS, as shown in XXII).
Formula XIII may also include compounds where n is 5 to 400 or from 10 to 300, both terminal R1 comprise monovalent reactive groups and the remaining R1 are independently of one another selected from monovalent alkyl groups having 1 to 18 carbon atoms which may have ether linkages between carbon atoms and may further comprise halogen.
One to four R1 in Formula XIII may comprise a vinyl carbonate or vinyl carbamate of Formula XXIIIa:
The silicone-containing vinyl carbonate or vinyl carbamate monomers specifically include: 1,3-bis[4-(vinyloxycarbonyloxy)but-1-yl]tetramethyl-disiloxane; 3-(vinyloxycarbonylthio) propyl-[tris (trimethylsiloxy)silane]; 3-[tris(trimethylsiloxy)silyl] propyl allyl carbamate; 3-[tris(trimethylsiloxy)silyl] propyl vinyl carbamate; trimethylsilylethyl vinyl carbonate; trimethylsilylmethyl vinyl carbonate, and the crosslinking agent of Formula XXIIIb.
Where biomedical devices with moduli below about 200 psi are desired, only one R1 comprises a monovalent reactive group and no more than two of the remaining R1 groups comprise monovalent siloxane groups.
Another suitable silicone-containing macromer is compound of Formula XXIV in which the sum of x and y is a number in the range of 10 to 30. The silicone containing macromer of Formula XXIV is formed by the reaction of fluoroether, hydroxy-terminated polydimethylsiloxane, isophorone diisocyanate and isocyanatoethylmethacrylate.
The non-hydroxyl containing silicone-containing component may be selected from non-hydroxyl containing acrylamide silicones of
In one embodiment where a modulus of less than about 120 psi is desired, the majority of the mass fraction of the silicone-containing components used in the lens formulation should contain only one polymerizable functional group.
The non-hydroxyl containing silicone component may be selected from the group consisting of monomethacryloxypropyl terminated, mono-n-alkyl terminated linear polydisubstituted siloxane; methacryloxypropyl-terminated linear polydisubstituted siloxane; and mixtures thereof.
The non-hydroxyl containing silicone component may also be selected from monomethacrylate terminated, C1-C4 alkyl terminated, linear polydimethylsiloxanes; and mixtures thereof.
In some instances, the non-hydroxyl functionalized silicone-containing component may be used in amounts up to about 10 wt%. Examples include those selected from mPDMS of Formula XXII where R5 is methyl or butyl, compounds of Formulae XXVIa, XVIIb through XVIIIb, XX, XXIa, XXIb and the macromers shown in Formula XXV or XXVI where n is n is 1-50 and m is 1-50, 1-20 or 1-10:
Specific examples of non-hydroxyl functionalized silicone-containing components include mPDMS of Formula XVIIa, compounds of Formulae XVIII or XIX where R1 is methyl and R5 is selected from methyl or butyl and the macromers shown in Formula XXV where n is 1-50 or 4-40, 4-20.
Specific examples of silicone containing crosslinkers include bismethacryloxypropyl polydimethyl siloxane, where n may be 4-200, or 4-150, and the following compounds of Formula XXVIIa-XXVIIIc, where n1 and n2 are independently selected from 4 to 100; 4 to 50; or 4 to 25; n3 is 1-50, 1-20 or 1-10; n is 1-100, 1-50, 1-20 or 1-10; m is 1-100, 1-50, 1-20 or 1-10; s is up to 50, 5-30 or 10-25; and q is up to 50, 5-30 or 10-25.
The non-hydroxyl containing silicone component may have an average molecular weight of from about 400 to about 4000 Daltons.
The silicone-containing component(s) (both hydroxyl and non-hydroxyl containing) may be present in amounts up to about 85 weight %, or from about 10 and about 80, or from about 20 and about 75 weight %, based upon all reactive components of the reactive mixture (e.g., excluding diluents).
The reactive monomer mixture may further comprise at least one reactive component which is charged under physiological conditions. The charged monomer may be selected from anions, cations, zwitterions, betaines, and mixtures thereof.
The charged monomers, when incorporated into the silicone hydrogels of the present invention, provide a net negative charge distribution. Anionic monomers comprise at least one anionic group and at least one reactive group. Specifically, the anionic group can include, but is not limited to, carboxylate groups, phosphates, sulfates, sulfonates, phosphonates, borates, and mixtures thereof. The anionic groups may comprise from three to ten carbon atoms, or from three to eight carbon atoms. The anionic groups may comprise carboxylic acid groups. Specifically, the charged monomer may be a carboxylic acid monomer selected from the group consisting of acrylic acid, methacrylic acid, furmaric acid, maelic acid, itaconic acid, crotonic acid, cinnamic acid, vinylbenzoic acid, monoesters of furmaric acid, maelic acid, and itaconic acid, and mixtures thereof.
The charged monomer may also comprise a mixture of anionic and cationic monomer.
The charged monomer can be a zwitterionic monomer. Zwitterionic monomers comprise at least one zwitterionic group and at least one reactive group. As used herein, the term "zwitterion" refers to a neutral chemical compound with both a positive and negative electrical charge. Zwitterionic monomers include betaine monomers.
The charged monomer can be a betaine monomer. Betaine monomers comprise at least one betaine group and at least one reactive group. As used herein, the term "betaine" refers to a neutral chemical compound with a positively charged cationic functional group such as a quaternary ammonium or phosphonium cation which bears no hydrogen atom and with negatively charged functional group such as a carboxylate group which may not be adjacent to the cationic site.
The charged monomer contains at least one polymerizable group, or reactive group. Reactive groups include groups that can undergo free radical polymerization. Non-limiting examples of free radical reactive groups include (meth)acrylates, styryls, vinyls, vinyl ethers, C1-6 alkyl(meth)acrylates, (meth)acrylamides, C1-6 alkyl (meth)acrylamides, N-vinyllactams, N-vinylamides, C2-12 alkenyls, C2-12 alkenylphenyls, C2-12 alkenylnaphthyls, C2-6 alkenylphenyl, C1-6 alkyls, O-vinylcarbamates, and O-vinylcarbonates.
Examples of "charged monomers" include (meth)acrylic acid, N-[(ethenyloxy)carbonyl]-β-alanine (VINAL,
The charged monomer may be selected from (meth)acrylic acid, 3-acrylamidopropanoic acid (ACA1), 5-acrylamidopropanoic acid (ACA2), and mixtures thereof..
The charged monomer can be present in an amount up to about 10 weight percent (wt. %), based on the total weight of the reaction monomer mixture, including a range of about 0.5 to about 5 wt.%, about 0.5 to about 3 wt.%, about 0.5 to about 2 wt.%, about 1 to about 10 wt.%, about 1 to about 5 wt.%, about 1 to about 3 wt.%, and about 1 to about 2 wt.%.
The reactive monomer mixture also includes at least one hydrophilic component selected from hydrophilic monomers and macromers. Hydrophilic monomers can be any of the hydrophilic monomers known to be useful to make hydrogels. Examples of suitable families of hydrophilic monomers include N-vinyl amides, N-vinylimides, N-vinyl lactams, (meth)acrylates, (meth)acrylamides, styrenes, vinyl ethers, O-vinyl carbonates, O-vinyl carbamates, N-vinyl ureas, other hydrophilic vinyl compounds and mixtures thereof.
The hydrophilic monomers that may be used to make the polymers of this invention have at least one polymerizable double bond and at least one hydrophilic functional group. Such hydrophilic monomers may themselves be used as crosslinking agents, however, where hydrophilic monomers having more than one polymerizable functional group are used, their concentration should be limited as discussed above to provide a contact lens having the desired modulus. The term "vinyl-type" or "vinyl-containing" monomers refer to monomers containing the vinyl grouping (-CH=CH2) and are generally highly reactive. Such hydrophilic vinyl-containing monomers are known to polymerize relatively easily.
"Acrylic-type" or "acrylic-containing" monomers are those monomers containing an acrylic group (CH2=CRCOX) wherein R is H or CH3, and X is O or N, which are also known to polymerize readily, such as N,N-dimethyl acrylamide (DMA), 2-hydroxyethyl methacrylamide, polyethyleneglycol monomethacrylate, methacrylic acid, acrylic acid, mixtures thereof and the like.
Non-limiting examples of hydrophilic (meth)acrylate and (meth)acrylamide monomers include: acrylamide, N-isopropyl acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, N,N-dimethyl acrylamide (DMA), N-2-hydroxyethyl (meth)acrylamide, 2,3-dihydroxypropyl (meth)acrylamide, N,N-bis(2-hydroxyethyl) (meth)acrylamide, N-(2-hydroxypropyl) (meth)acrylamide, N,N-bis(2-hydroxypropyl) (meth)acrylamide, N-(3-hydroxypropyl) (meth)acrylamide, vinyl acetate, acrylonitrile, and mixtures thereof.
Non-limiting examples of hydrophilic N-vinyl lactam and N-vinyl amide monomers include: N-vinyl pyrrolidone (NVP), N-vinyl-2-piperidone, N-vinyl-2-caprolactam, N-vinyl-3-methyl-2-caprolactam, N-vinyl-3-methyl-2-piperidone, N-vinyl-4-methyl-2-piperidone, N-vinyl-4-methyl-2-caprolactam, N-vinyl-3-ethyl-2- pyrrolidone, N-vinyl-4,5-dimethyl-2-pyrrolidone, N-vinyl acetamide (NVA), N-vinyl-N-methylacetamide (VMA), N-vinyl-N-ethyl acetamide, N-vinyl-N-ethyl formamide, N-vinyl formamide, N-vinyl-N-methylpropionamide, N-vinyl-N-methyl-2-methylpropionamide, N-vinyl-2-methylpropionamide, N-vinyl-N,N'-dimethylurea, 1-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone; 1-ethyl-5-methylene-2-pyrrolidone, N-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone, 1-N-propyl-3-methylene-2-pyrrolidone, 1-N-propyl-5-methylene-2-pyrrolidone, 1-isopropyl-3-methylene-2-pyrrolidone, 1-isopropyl-5-methylene-2-pyrrolidone, N-vinyl-N-ethyl acetamide, N-vinyl-N-ethyl formamide, N-vinyl formamide, N-vinyl isopropylamide, N-vinyl caprolactam, N-carboxyvinyl-β-alanine (VINAL), N-carboxyvinyl-α-alanine, N-vinylimidazole, and mixtures thereof.
Non-limiting examples of hydrophilic O-vinyl carbamates and O-vinyl carbonates monomers include: N-2-hydroxyethyl vinyl carbamate and N-carboxy-β-alanine N-vinyl ester. Further examples of the hydrophilic vinyl carbonate or vinyl carbamate monomers are disclosed in
Other hydrophilic vinyl compounds include ethylene glycol vinyl ether (EGVE), di(ethylene glycol) vinyl ether (DEGVE), allyl alcohol, 2-ethyl oxazoline, vinyl acetate, acrylonitrile, and mixtures thereof.
Other suitable hydrophilic monomers will be apparent to one skilled in the art.
The hydrophilic components of the present invention may also be macromers of linear or branched poly(ethylene glycol), poly(propylene glycol), or statistically random or block copolymers of ethylene oxide and propylene oxide. The macromers of these polyethers have one or more reactive group. Non-limiting examples of such reactive groups are acrylates, methacrylates, styrenes, vinyl ethers, acrylamides, methacrylamides, and other vinyl compounds. In one embodiment, the macromers of these polyethers comprise (meth)acrylates, (meth)acrylamides, and mixtures thereof.
The hydrophilic monomers which may be incorporated into the polymers disclosed herein may be selected from N,N-dimethyl acrylamide (DMA), 2-hydroxyethyl acrylamide, 2-hydroxyethyl methacrylamide, N-hydroxypropyl methacrylamide, bishydroxyethyl acrylamide, 2,3-dihydroxypropyl (meth)acrylamide, N-vinylpyrrolidone (NVP), N-vinyl-N-methyl acetamide, N-vinyl methacetamide (VMA), and polyethyleneglycol monomethacrylate.
The hydrophilic monomers may be selected from DMA, NVP, VMA, NVA, and mixtures thereof.
It is a surprising effect of the present invention that silicone hydrogels with a desirable balance of wettability, water content and biocompatibility may be formed from reaction mixtures with 35 wt%, or less or less than about 30 wt%, or less than about 25 wt%, or less than about 20 wt% hydrophilic amide monomers. The hydrophilic amide monomers may be included in the reactive mixtures of the present invention in amounts between about 5 and 28 wt%, or 5 and about 25 wt%, or between about 8 and about 20 wt%.
The hydrophilic components (including the charged components and the hydrophilic hydroxyl components (discussed below), but excluding the polyamide) may be present in amounts up to about 50 wt%, or in an amount in the range of about 10 to about 50 wt. %, or in the range of about 10 to about 40 wt. %, based on the total weight of the reactive components in the reactive monomer mixture.
The reactive mixtures of the present invention may further comprise, in addition to the hydrophilic monomer described above, at least one hydroxyalkyl (meth)acrylate where the hydroxyl alkyl group may be selected from C2-C4 mono or dihydroxy substituted alkyl, and poly(ethylene glycol) having 1-10 repeating units; or is selected from 2-hydroxyethyl, 2,3-dihydroxypropyl, or 2-hydroxypropyl.
Examples of suitable hydroxyalkyl (meth)acrylate monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 1-hydroxypropyl-2-(meth)acrylate, 2-hydroxy-2-methylpropyl (meth)acrylate, 3-hydroxy-2,2-dimethyl-propyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, polyethyleneglycol monomethacrylate, and mixtures thereof.
The hydroxyalkyl monomer may also be selected from the group consisting of 2-hydroxyethyl methacrylate, glycerol methacrylate, 2-hydroxypropyl methacrylate, hydroxybutyl methacrylate, 3-hydroxy-2,2-dimethyl-propyl methacrylate, and mixtures thereof.
The hydroxyalkyl monomer may comprise 2-hydroxyethyl methacrylate, 3-hydroxy-2,2-dimethyl-propyl methacrylate, hydroxybutyl methacrylate or glycerol methacrylate.
Hydroxyl containing (meth)acrylamides are generally too hydrophilic to be included as compatibilizing hydroxyalkyl monomers, and when included are hydrophilic monomers.
When at least one hydroxyalkyl methacrylate is included, the lower amount of hydroxyalkyl monomers may be selected to provide a haze value to the final lens of less than about 50% or less than about 30%.
It will be appreciated that the amount of hydroxyl component will vary depending upon a number of factors, including, the number of hydroxyl groups on the hydroxyalkyl monomer, the amount, molecular weight and presence of hydrophilic functionality on the silicone containing components. The hydrophilic hydroxyl component may be present in the reactive mixture in amounts up to about 15%, up to about 10 wt%, between about 3 and about 15 wt% or about 5 and about 15 wt%.
It is generally desirable to add one or more cross-linking agents to the reaction mixture. The cross-linking agents may be selected from bifunctional cross-linkers, trifunctional cross-linkers, tetrafunctional cross-linkers, including silicone-containing and non-silicone containing cross-linking agents, and mixtures thereof. Non-silicone containing cross-linking agents include ethylene glycol dimethacrylate ("EGDMA"), diethyleneglycol dimethacrylate; tetraethylene glycol dimethacrylate (TEGDMA), trimethylolpropane trimethacrylate ("TMPTMA"), glycerol trimethacrylate, 1,3-propanediol dimethacrylate; 2,3-propanediol dimethacrylate; 1,6-hexanediol dimethacrylate; 1,4-butanediol dimethacrylate; triallyl cyanurate (TAC), methacryloxyethyl vinylcarbonate (HEMAVc), allylmethacrylate, methylene bisacrylamide (MBA), polyethylene glycol dimethacrylate (wherein the polyethylene glycol has a molecular weight up to about 5000 Daltons). The cross-linking agents are used in amounts from about 0.000415 to about 0.0156 moles per 100 grams of reactive components in the reaction mixture. Alternatively, if the hydrophilic monomers and/or the silicone-containing components are multifunctional or contain multifunctional impurities, the addition of a crosslinking agent to the reaction mixture is optional. Examples of hydrophilic monomers which can act as the crosslinking agent and when present do not require the addition of an additional crosslinking agent to the reaction mixture include (meth)acrylate and (meth)acrylamide endcapped polyethers.
The reactive monomer mixture may contain additional components such as, but not limited to, diluents, wetting agents, light absorbing compounds, including UV absorbers and photochromic compounds, tints, pigment and dyes, any of which may be reactive or non-reactive, but capable of being retained in the biomedical device, medicinal agents, antimicrobial compounds, pharmaceutical compounds, nutriceutical compounds, release agents, releasable wetting agents, and combinations thereof.
The reactive components may be mixed in a diluent to form a reaction mixture. Suitable diluents are known in the art. For silicone hydrogels suitable diluents are disclosed in
Classes of suitable diluents for silicone hydrogel reaction mixtures include alcohols having 2 to 20 carbons, amides having 10 to 20 carbon atoms derived from primary amines, and carboxylic acids having 8 to 20 carbon atoms. Primary and tertiary alcohols may be used. Preferred classes include alcohols having 5 to 20 carbons and carboxylic acids having 10 to 20 carbon atoms.
Specific diluents which can be used include 1-ethoxy-2-propanol, diisopropylaminoethanol, isopropanol, 3,7-dimethyl-3-octanol, 1-decanol, 1-dodecanol, 1-octanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 2-octanol, 3-methyl- 3-pentanol, tert-amyl alcohol, tert-butanol, 2-butanol, 1-butanol, 2-methyl-2-pentanol, 2-propanol, 1-propanol, ethanol, 2-ethyl-1-butanol, (3-acetoxy-2-hydroxypropyloxy) propylbis(trimethylsiloxy)methylsilane, 1-tert-butoxy-2-propanol, 3,3-dimethyl-2-butanol, tert-butoxyethanol, 2-octyl-1-dodecanol, decanoic acid, octanoic acid, dodecanoic acid, 2-(diisopropylamino)ethanol mixtures thereof and the like.
The diluents may include 3,7-dimethyl-3-octanol, 1-dodecanol, 1-decanol, 1-octanol, 1-pentanol, 1-hexanol, 2-hexanol, 2-octanol, 3-methyl-3-pentanol, 2-pentanol, t-amyl alcohol, tert-butanol, 2-butanol, 1-butanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, ethanol, 3,3-dimethyl-2-butanol, 2-octyl-1-dodecanol, decanoic acid, octanoic acid, dodecanoic acid, mixtures thereof and the like.
The diluents may include 3,7-dimethyl-3-octanol, 1-dodecanol, 1-decanol, 1-octanol, 1-pentanol, 1-hexanol, 2-hexanol, 2-octanol, 1-dodecanol, 3-methyl-3-pentanol, 1-pentanol, 2-pentanol, t-amyl alcohol, tert-butanol, 2-butanol, 1-butanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-octyl-1-dodecanol, mixtures thereof and the like.
Mixtures of diluents may be used. If a diluent is present, generally there are no particular restrictions with respect to the amount of diluent present. When diluent is used, the diluent may be present in an amount in the range of about 2 to about 70 wt%, including in the range of about 5 to about 50 wt%, about 5 to about 45wt%, about 15 to about 40 wt%, based on the total weight of the reactive mixtures (including reactive and nonreactive components).
A polymerization catalyst may be used in the reaction mixture. The polymerization catalyst or initiator can include at least one of lauryl peroxide, benzoyl peroxide, iso- propyl percarbonate, azobisisobutyronitrile, and the like, that generate free radicals at moderately elevated temperatures, and photoinitiator systems such as aromatic alpha-hydroxy ketones, alkoxyoxybenzoins, acetophenones, acylphosphine oxides, bisacylphosphine oxides, and a tertiary amine plus a diketone, mixtures thereof and the like. Illustrative examples of photoinitiators are 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentyl phosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenyl phosphinthere of eoxide (Irgacure 819), 2,4,6-trimethylbenzyldiphenyl phosphine oxide and 2,4,6-trimethylbenzoyl diphenylphosphine oxide, benzoin methyl ester and a combination of cam- phorquinone and ethyl 4-(N,N-dimethylamino)benzoate.
Commercially available visible light initiator systems include Irgacure® 819, Irgacure® 1700, Irgacure® 1800, Irgacure® 819, Irgacure® 1850 (all from Ciba Specialty Chemicals) and Lucrin® TPO initiator (available from BASF). Commercially available UV photoinitiators include Darocur® 1173 and Darocur® 2959 (Ciba Specialty Chemicals). These and other photoinitiators which may be used are disclosed in
Polymerization of the reaction mixture can be initiated using the appropriate choice of heat or visible or ultraviolet light or other means depending on the polymerization initiator used. Alternatively, initiation can be conducted without a photoinitiator using, for example, e-beam.
The reactive mixtures of the present invention can be formed by any of the methods known in the art, such as shaking or stirring, and used to form polymeric articles or devices by known methods. The reactive components (hydrophilic monomer, hydroxyl-containing silicone component, cross-linking agent, polyamide, etc.) are mixed together either with or without a diluent to form the reactive mixture.
For examples, the silicone hydrogels may be prepared by mixing reactive components, and, optionally, diluent(s), with a polymerization initiator and curing by appropriate conditions to form a produce that can be subsequently formed into the appropriate shape by lathing, cutting, and the like. Alternatively, the reaction mixture may be placed in a mold and subsequently cure into the appropriate article.
The reactive mixture of the present invention may be cured via any known process for molding the reaction mixture in the production of contact lenses, including spincasting and static casting. Spincasting methods are disclosed in
After curing, the lens may be subjected to extraction to remove unreacted components and release the lens from the lens mold. The extraction may be done using conventional extraction fluids, such organic solvents, such as alcohols or may be extracted using aqueous solutions.
Aqueous solutions are solutions which comprise water. The aqueous solutions of the present invention may comprise at least about 30 weight % water, or at least about 50 weight % water, or at least about 70% water, or at least about 90 weight % water. Aqueous solutions may also include additional water soluble components such as release agents, wetting agents, slip agents, pharmaceutical and nutraceutical components, combinations thereof and the like. Release agents are compounds or mixtures of compounds which, when combined with water, decrease the time required to release a contact lens from a mold, as compared to the time required to release such a lens using an aqueous solution that does not comprise the release agent. The aqueous solutions may comprise less than about 10 weight %, or less than about 5 weight % organic solvents such as isopropyl alcohol, or may be free from organic solvents. The aqueous solutions may not require special handling, such as purification, recycling or special disposal procedures.
In various embodiments, extraction can be accomplished, for example, via immersion of the lens in an aqueous solution or exposing the lens to a flow of an aqueous solution. In various embodiments, extraction can also include, for example, one or more of: heating the aqueous solution; stirring the aqueous solution; increasing the level of release aid in the aqueous solution to a level sufficient to cause release of the lens; mechanical or ultrasonic agitation of the lens; and incorporating at least one leach aid in the aqueous solution to a level sufficient to facilitate adequate removal of unreacted components from the lens. The foregoing may be conducted in batch or continuous processes, with or without the addition of heat, agitation or both.
Some embodiments can also include the application of physical agitation to facilitate leach and release. For example, the lens mold part to which a lens is adhered can be vibrated or caused to move back and forth within an aqueous solution. Other embodiments may include ultrasonic waves through the aqueous solution.
The lenses may be sterilized by known means such as, but not limited to autoclaving.
The contact lenses of the present invention display desirable combination of both mechanical and biological properties including water content, haze, contact angle, modulus, oxygen permeability, lipid uptake, lysozyme uptake and PQ1 uptake, as shown in the following table. All values are prefaced by "about", and the ophthalmic devices of the present invention may have any combination of the listed properties.
Lysozyme uptake may also be at least about 800 or between 50 and 1500, 100-1500 or 200-1500 µg/lens.
In addition to displaying desirable stability, the lenses of the present invention also display compatibility with the components of human tears.
It will be appreciated that all of the tests specified herein have a certain amount of inherent error. Standard deviations are shown in parentheses. Accordingly, the results reported herein are not to be taken as absolute numbers, but numerical ranges based upon the precision of the particular test.
Haze was measured by placing a hydrated test lens in borate buffered saline in a clear glass cell at ambient temperature above a flat black background, illuminating from below with a fiber optic lamp (Dolan-Jenner PL-900 fiber optic light with 0.5 inch diameter light guide) at an angle of 66° normal to the lens cell, and capturing an image of the test lens from above, normal to the glass cell with a video camera (DVC 1310C RGB camera or equivalent equipped with a suitable zoom camera lens) placed 14 cm above the lens holder. The background scatter is subtracted from the scatter of the test lens by subtracting an image of a blank cell with borate buffered saline (baseline) using EPIX XCAP V 3.8 software. The subtracted scattered light image is quantitatively analyzed by integrating over the central 10 mm of the test lens and then compared to a frosted glass standard.
The light intensity/power setting was adjusted to achieve a mean grayscale value in the range of 900-910 for the frosted glass standard; at this setting, the baseline mean grayscale value was in the range of 50-70. The mean grayscale values of the baseline and frosted glass standard are recorded and used to create a scale from zero to 100, respectively. In the grayscale analysis, the mean and standard deviations of the baseline, frosted glass, and every test lens was recorded. For each lens, a scaled value was calculated according to the equation: scaled value equals the mean grayscale value (lens minus baseline) divided by the mean grayscale value (frosted glass minus baseline) times by 100. Three to five test lenses are analyzed, and the results are averaged.
Water content was measured gravimetrically. Lenses were equilibrated in packing solution for 24 hours. Each of three test lens are removed from packing solution using a sponge tipped swab and placed on blotting wipes which have been dampened with packing solution. Both sides of the lens are contacted with the wipe. Using tweezers, the test lens are placed in a tared weighing pan and weighed. The two more sets of samples are prepared and weighed. All weight measurements were done in triplicate, and the average of those values used in the calculations. The wet weight is defined as the combined weight of the pan and wet lenses minus the weight of the weighing pan alone.
The dry weight was measured by placing the sample pans in a vacuum oven which has been preheated to 60°C for 30 minutes. Vacuum was applied until the pressure reaches at least 1 inch of Hg is attained; lower pressures are allowed. The vacuum valve and pump are turned off and the lenses are dried for at least 12 hours; typically overnight. The purge valve is opened allowing dry air or dry nitrogen gas to enter. The oven is allowed reach atmospheric pressure. The pans are removed and weighed. The dry weight is defined as the combined weight of the pan and dry lenses minus the weight of the weighing pan alone. The water content of the test lens was calculated as follows:
The average and standard deviation of the water content were calculated and the average value reported as the percent water content of the test lens.
The refractive index (RI) of a contact lens was measured by a Leica ARIAS 500 Abbe refractometer in manual mode or by a Reichert ARIAS 500 Abbe refractometer in automatic mode with a prism gap distance of 100 microns. The instrument was calibrated using deionized water at 20°C (+/- 0.2 °C). The prism assembly was opened and the test lens placed on the lower prism between the magnetic dots closest to the light source. If the prism is dry, a few drops of saline were applied to the bottom prism. The front curve of the lens was against the bottom prism. The prism assembly was then closed. After adjusting the controls so that the shadow line appeared in the reticle field, the refractive index was measured. The RI measurement was made on five test lenses. The average RI calculated from the five measurements was recorded as the refractive index as well as its standard deviation.
Oxygen permeability (Dk) was determined by the polarographic method generally described in ISO 9913-1:1996 and ISO 18369-4:2006, but with the following modifications. The measurement was conducted at an environment containing 2.1% oxygen created by equipping the test chamber with nitrogen and air inputs set at the appropriate ratio, for example, 1800 mL/min of nitrogen and 200 mL/min of air. The t/Dk is calculated using the adjusted oxygen concentration. Borate buffered saline was used. The dark current was measured by using a pure humidified nitrogen environment instead of applying MMA lenses. The lenses were not blotted before measuring. Four lenses were stacked instead of using lenses of various thickness (t) measured in centimeters. A curved sensor was used in place of a flat sensor; radius was 7.8 mm. The calculations for a 7.8 mm radius sensor and 10% (v/v) air flow are as follows:
The edge correction was related to the Dk of the material.
For all Dk values less than 90 barrers:
For Dk values between 90 and 300 barrers:
For Dk values greater than 300 barrers:
Non-edge corrected Dk was calculated from the reciprocal of the slope obtained from the linear regression analysis of the data wherein the x variable was the center thickness in centimeters and the y variable was the t/Dk value. On the other hand, edge corrected Dk was calculated from the reciprocal of the slope obtained from the linear regression analysis of the data wherein the x variable was the center thickness in centimeters and the y variable was the edge corrected t/Dk value. The resulting Dk value was reported in barrers.
Wettability of lenses was determined using the methods below. Dynamic contact angle (DCA) was determined by a Wilhelmy plate method using a Cahn DCA-315 instrument at room temperature and using deionized water as the probe solution. The experiment was performed by dipping the lens specimen of known parameter into the packing solution of known surface tension while measuring the force exerted on the sample due to wetting by a sensitive balance. The advancing contact angle of the packing solution on the lens is determined from the force data collected during sample dipping. The receding contact angle is likewise determined from force data while withdrawing the sample from the liquid. The Wilhelmy plate method is based on the following formula: Fg = γρcosθ - B, wherein F = the wetting force between the liquid and the lens (mg), g = gravitational acceleration (980.665 cm/sec2), γ = surface tension of probe liquid (dyne/cm), ρ = the perimeter of the contact lens at the liquid/lens meniscus (cm), θ = the dynamic contact angle (degree), and B = buoyancy (mg). B is zero at the zero depth of immersion. Four test strips were cut from the central area of the contact lens. Each strip was approximately 5 mm in width and equilibrated in packing solution. Then, each sample was cycled four times, and the results were averaged to obtain the advancing and receding contact angles of the lens.
Wettability of lenses was also determined using a sessile drop technique measured using KRUSS DSA-100 TM instrument at room temperature and using DI water as probe solution. The lenses to be tested (3-5/sample) were rinsed in DI water to remove carry over from packing solution. Each test lens was placed on blotting lint free wipes which were dampened with packing solution. Both sides of the lens were contacted with the wipe to remove surface water without drying the lens. To ensure proper flattening, lenses were placed "bowl side down" on the convex surface of contact lens plastic molds. The plastic mold and the lens were placed in the sessile drop instrument holder, ensuring proper central syringe alignment. A 3 to 4 microliter drop of deionized water was formed on the syringe tip using DSA 100-Drop Shape Analysis software ensuring the liquid drop was hanging away from the lens. The drop was released smoothly on the lens surface by moving the needle down. The needle was withdrawn away immediately after dispensing the drop. The liquid drop was allowed to equilibrate on the lens for 5 to 10 seconds, and the contact angle was measured between the drop image and the lens surface.
The mechanical properties of the contact lenses were measured by using a tensile testing machine such as an Instron model 1122 or 5542 equipped with a load cell and pneumatic grip controls. Minus one diopter lens is the preferred lens geometry because of its central uniform thickness profile. A dog-bone shaped sample cut from a -1.00 power lens having a 0.522 inch length, 0.276 inch "ear" width and 0.213 inch "neck" width was loaded into the grips and elongated at a constant rate of strain of 2 inches per minute until it breaks. The center thickness of the dog-bone sample was measured using an electronic thickness gauge prior to testing. The initial gauge length of the sample (Lo) and sample length at break (Lf) were measured. At least five specimens of each composition were measured, and the average values were used to calculate the percent elongation to break: percent elongation = [(Lf - Lo)/Lo] × 100. The tensile modulus was calculated as the slope of the initial linear portion of the stress-strain curve; the units of modulus are pounds per square inch or psi. The tensile strength was calculated from the peak load and the original cross-sectional area: tensile strength = peak load divided by the original cross-sectional area; the units of tensile strength are psi. Toughness was calculated from the energy to break and the original volume of the sample: toughness = energy to break divided by the original sample volume; the units of toughness are in-lbs/in3.
PQ1 uptake was measured chromatographically. The HPLC was calibrated using a series of standard PQ1 solutions having concentrations 2, 4, 6, 8, 12 and 15 µg/mL. Lenses were placed into polypropylene contact lens cases with 3 mL of Optifree Replenish or similar lens solution (PQ1 concentration = 10 micrograms/mL) which is commercially available from Alcon. A control lens case, containing 3 mL of solution, but no contact lens was also prepared. The lenses and control solutions were stored at room temperature for 72 hours. 1 mL of solution was removed from each of the samples and controls and mixed with trifluoroacetic acid (10 µL). The analysis was conducted using HPLC/ELSD and a Phenomenex Luna C5 (4.6 mm × 5 mm; 5 µm particle size) column with the following equipment and conditions: Agilent 1200 HPLC or equivalent with an ELSD operating at T= 100°C, Gain = 12, Pressure = 4.4 bar, Filter = 3s; ELSD parameters may vary from instrument to instrument; using mobile phase A of water (0.1% TFA) and mobile phase B of acetonitrile (0.1% TFA), a column temperature of 40°C and an injection volume of 100 µL. An elution profile was used and listed in Table A. A calibration curve was created by plotting the peak area value as a function of the concentration of the PQ1 standard solutions. The concentration of PQ1 in a sample was then calculated by solving the quadratic equation representing the calibration curve. Three lenses were run for each analysis, and the results were averaged. PQ1 uptake was reported as the percentage loss of PQ1 after soak with lens compared to the PQ1 present in the control without lens.
The amount of cholesterol absorbed by a contact lens was determined by a LC-MS method (lipid uptake in the data tables). Lenses were soaked in a cholesterol solution and then extracted with dichloromethane. The dichloromethane extract was evaporated and reconstituted with a heptane/isopropanol mixture with subsequent analysis by LC-MS. The results were reported as micrograms of cholesterol per lens. A deuterated cholesterol internal standard was used to improve accuracy and precision of the method.
A cholesterol stock solution was prepared by placing 15.0 ± 0.5 milligrams of cholesterol into a wide-mouth 10 mL glass volumetric flask followed by dilution with isopropanol.
A cholesterol soak solution was prepared by placing 0.430 ± 0.010 grams of lysozyme (purity = 93%), 0.200 ± 0.010 grams of albumin, and 0.100 ± 0.010 grams of β-lactoglobulin into a 200 mL glass volumetric flask, adding approximately 190 milliliters of PBS to the flask, and swirling to dissolve the contents. 2 Milliliters of the cholesterol stock solution was then added and diluted to volume with PBS. The volumetric flask was capped and shaken well. The concentration of the cholesterol soak solution was approximately 15 µg/mL. Note: The mass of these components may be adjusted to account for lot-to-lot purity variability so that the target concentrations can be achieved.
Six contact lenses were removed from their packages and blotted with lint-free paper towels to remove excess packing solution. The lenses were placed into six separate 8 mL glass vials (one lens per vial), and 3.0 mL of the cholesterol soak solution was added to each vial. The vials were capped and placed into a New Brunswick Scientific incubator-shaker for 72 hours at 37°C and 100 rpm. After incubation, each lens was rinsed three times with PBS in 100 mL beakers and placed into a 20-mL scintillation vial.
To each lens-containing scintillation vial, 5 mL of dichloromethane and 100 µL of the internal standard solution were added. After a minimum of 16 hours of extraction time, the supernatant liquid was transferred into a 5 mL disposable glass culture tube. The tube was placed into the Turbovap and the solvent completely evaporated. Place 1mL of the diluent into the culture tube and re-dissolve the contents. The aforementioned diluent was a 70:30 (v/v) mixture of heptane and isopropanol. The diluent was also the mobile phase. The resulting solution was carefully transferred into an autosampler vial and ready for LC-MS analysis.
An internal standard stock solution was prepared by weighing approximately 12.5 + 2 mg of deuterated cholesterol (2,2,3,4,4,6-d6-cholesterol) in a 25 mL volumetric flask followed by dilution with the diluent. The concentration of the internal standard stock solution was approximately 500 µg/mL.
An internal standard solution was prepared by placing 1.0 mL of the internal standard stock solution in a 50mL volumetric flask followed by dilution to volume with diluent. The concentration of this intermediate internal standard solution is approximately 10 µg/mL.
A reference standard stock solution was prepared by weighing approximately 50 + 5 mg of cholesterol in a 100 mL volumetric flask followed by dilution with diluent. The concentration of the cholesterol in this reference stock solution is approximately 500 µg/mL.
Working standard solutions were then made according to Table 2 by placing the appropriate amount of standard solutions into the listed 25-mL, 50-mL or 100-mL volumetric flasks. After the standard solutions were added to the volumetric flasks, the mixture was diluted to volume with diluent and swirled well.
The following LC-MS analysis was performed:
- (1) Make 6 injections of the "Std4" to evaluate system suitability. The RSD% of the peak areas for the working standards and the internal standards must be < 5% and RSD(%) of their peak area ratios must be < 7% to pass system suitability.
- (2) Inject working standards 1-6 to create a calibration curve. The square of the correlation coefficient (r2) must be > 0.99.
- (3) Inject test samples followed by a bracketing standard (Std4). The peak area ratio of the bracketing standard must be within ± 10% of the averaged peak area ratio from the system suitability injections.
A calibration curve was constructed by plotting the peak area ratio (reference std/internal std) value that corresponds to the concentration of each working standard solution. The concentration of cholesterol in sample is calculated by solving a quadratic equation. Typical equipment and their settings for the LC-MS analysis are listed below and shown in Tables C and D. The values for the instrument tune parameters may change each time the mass spectrometer is tuned.
- Temperature: 45°C
- Time: 30 minutes or more to dryness
- Gas: nitrogen @ 5psi
- HPLC: Thermo Accela HPLC Instrument or equivalent
- HPLC Column: Agilent Zorbax NH2 (4.6 mm × 150 mm; 5 µm particle size)
- Mobile Phase: 70% heptane and 30% isopropanol
- Column Temperature: 30 °C
- Injection Volume: 25 µL
- Flow Rate: 1000 µL/min
The amount of lysozyme uptake by a contact lens was measured by a HPLC-UV method. Lysozyme uptake was determined as the difference of lysozyme content in phosphate-buffered saline solution (PBS) before contact lenses are immersed and the concentration in the test solution after 72 hours of lens immersion at 37°C.
A lysozyme soak solution was prepared by placing 0.215 ± 0.005 grams of lysozyme (purity = 93%) into a 100 mL volumetric flask followed by adding 50 mL of PBS to dissolve the lysozyme by swirling followed by dilution to volume with PBS. The resulting lysozyme soak solution was filtered/sterilized using a Millipore Stericup filtration device. The concentration of the lysozyme soak solution is approximately 2000 µg/mL. The mass of lysozyme may be adjusted to account for lot-to-lot purity variability so that a 2000 µg/mL concentration can be achieved.
Three contact lenses were removed from their packages and blotted with lint-free paper towel to remove excess packing solution. The lenses were placed into three separate 8 mL glass vials (one lens per vial). 1.5 mL of the lysozyme soak solution was added to each vial. The vials were capped and inspected to ensure each lens was completely immersed in the soak solution. As control samples, 1.5 mL of lysozyme soak solution were added into three separate 8 mL glass vials. The samples were then incubated on a New Brunswick Scientific incubator-shaker for 72 hours at 37°C and 100 rpm.
A diluent was prepared by mixing 900 mL water, 100 mL acetonitrile and 1 mL trifluoroacetic acid into a 1L glass bottle.
A lysozyme stock solution was prepared by placing 0.240 ± 0.010 grams of lysozyme (purity = 93%) into a 100 mL volumetric flask followed by dilution to volume with diluent. The concentration of the lysozyme stock solution is approximately 2200 µg/mL.
shown in Table E, a series of working standard solutions was prepared by mixing the appropriate amounts of lysozyme stock solution with diluent using 5 mL volumetric flasks.
A 10% (v/v) solution was prepared by adding 1 mL of trifluoroacetic acid into a 10 mL glass volumetric flask followed by dilution with HPLC water. Samples for HPLC-UV analysis were prepared as follows: (1) by placing 1000 µL of test sample and 10 µL of the 10% TFA solution into an autosampler vial or (2) by placing 1000 µL of reference standard and 10 µL of reference standard diluent into an autosampler vial.
The analysis involved the following steps:
- (1) Perform 6 injections of the "Std4" to evaluate system suitability. The RSD% of the peak areas and retention times must be < 0.5% to pass system suitability.
- (2) Inject working standards 1-6 to create a calibration curve. The square of the correlation coefficient (r2) must be > 0.99.
- (3) Inject test samples followed by a bracketing standard (Std4). The peak area of the bracketing standard must be ± 1% of the averaged peak areas from the system suitability injections.
A calibration curve was constructed by plotting the peak area value that corresponds to the concentration of each lysozyme working standard solution. The concentration of lysozyme in the test samples was calculated by solving a linear equation. Typical equipment and their settings are listed below or shown in Table F.
- Instrument: Agilent 1200 HPLC with UV detection (or equivalent HPLC-UV)
- Detection: UV @ 280 nm (5 nm bandwidth)
- Column: Phenomenex Luna C5 (50 × 4.6 mm) or Agilent PLRP-S (50 × 4.6 mm)
- Mobile Phase A: H2O (0.1% TFA)
- Mobile Phase B: Acetonitrile (0.1% TFA)
- Column Temperature: 40 °C
- Injection Volume: 10 µL
Alternatively, lysozyme uptake was measured as follows. A lysozyme solution was prepared from chicken egg white (Sigma, L7651) at a concentration of 2 mg/mL in phosphate saline buffer supplemented by sodium bicarbonate at 1.37g/L and D-glucose at 0.1 g/L.
Three lenses for each test sample were tested using each protein solution, and three were tested using PBS as a control solution. The test lenses were blotted on sterile gauze to remove packing solution and aseptically transferred, using sterile forceps, into sterile 24 well cell culture plates (one lens per well) each well containing 2 mL of the lysozyme solution. Each lens was fully immersed in the solution. As controls, 2 mL of the lysozyme solution was placed in wells without a contact lens.
The plates were sealed using parafilm to prevent evaporation and dehydration and placed onto an orbital shaker and incubated at 35°C with agitation at 100 rpm for 72 hours. After the 72 hour incubation period, the lenses were rinsed 3 to 5 times by dipping lenses into 200 mL of PBS. The lenses were blotted on a paper towel to remove excess PBS and transferred into sterile conical tubes (1 lens per tube), each tube containing a volume of PBS determined based upon an estimate of lysozyme uptake expected based upon on each lens composition. The lysozyme concentration in each tube to be tested must be within the albumin standards range as described by the manufacturer (0.05 micrograms to 30 micrograms). Samples known to uptake a level of lysozyme lower than 100 µg per lens were diluted 5 times. Samples known to uptake levels of lysozyme higher than 500 µg per lens were diluted 20 times.
Lysozyme uptake was determined using on-lens bicinchoninic acid method using QP-BCA kit ( Sigma, QP-BCA) following the procedure described by the manufacturer and was calculated by subtracting the optical density measured on PBS soaked lenses from the optical density determined on lenses soaked in lysozyme solution. The optical density was measured using a Synergy II Micro-plate reader capable of reading optical density at 562 nm.
The invention is now described with reference to the following examples. Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.
The following abbreviations will be used throughout the Examples and have the following meanings:
- BC: back curve plastic mold
- FC: front curve plastic mold
- RMM: reactive monomer mixture
- NVP: N-vinylpyrrolidone (Acros or Aldrich)
- DMA: N, N-dimethylacrylamide (Jarchem)
- HEMA: 2-hydroxyethyl methacrylate (Bimax)
- HPMA: 2-hydroxypropyl methacrylate
- HEAA: 2-hydroxyethyl acrylate
- Bis-HEAA: N,N-bis(2-hydroxyethyl) acrylamide
- GMMA: 2,3-dihydroxypropyl methacrylate
- HBMA: 2-hydroxybutyl methacrylate
- VMA: N-vinyl N-methyl acetamide (Aldrich)
- AA: acrylic acid
- MAA: methacrylic acid (Acros)
- VINAL: N-[(ethenyloxy)carbonyl]-β-alanine;
CAS #148969-96-4 - ACA1: 3-acrylamidopropanoic acid
- ACA2: 5-acrylamidopropanoic acid
- Q Salt or METAC: 2-(methacryloyloxy)ethyl trimethylammonium chloride
- AMPS: 2-acrylamido-2-methylpropane sulfonic acid
- CBT: 1-Propanaminium, N-(2-carboxyethyl)-N,N-dimethyl-3-[(1-oxo-2-propen-1-yl)amino]-, inner salt; carboxybetaine;
CAS 79704-35-1 - SBT: 1-Propanaminium, N,N-dimethyl-N-[3-[(1-oxo-2-propen-1-yl)amino]propyl]-3-sulfo-, inner salt; sulfobetaine;
CAS 80293-60-3 - PBT: 3,5-Dioxa-8-aza-4-phosphaundec-10-en-1-aminium, 4-hydroxy-N,N,N-trimethyl-9-oxo-, inner salt, 4-oxide (9CI); phosphobetaine;
CAS 163674-35-9 - Blue HEMA: 1-amino-4-[3-( 4-(2-methacryloyloxy-ethoxy)-6-chlorotriazin-2-ylamino)-4-sulfophenylamino]anthraquinone-2-sulfonic acid, as described in
US Patent No. 5,944,853 - Styryl-TRIS: tris(trimethylsiloxy)silyl styrene (Melrob)
- PVMA: poly(N-vinyl N-methyl acetamide)
- PVP: poly(N-vinylpyrrolidone) (ISP Ashland)
- Poly[DMA-NVP]: random or block copolymer of DMA and NVP
- Poly[DMA-CBT]: random or block copolymer of DMA and CBT
- EGDMA: ethylene glycol dimethacrylate (Esstech)
- TEGDMA: tetraethylene glycol dimethacrylate (Esstech)
- TMPTMA: trimethylolpropane trimethacrylate (Esstech)
- MBA: methylene bisacrylamide (Aldrich)
- TAC: Triallyl Cyanurate (Polysciences)
- BMPP: 2,2-bis(4-methacryloxyphenyl)-propane (Polysciences)
- BAPP: 2,2-bis[4-(2-acryloxyethoxy)phenyl]propane (Polysciences)
- BHMPP: 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (Polysciences)
- Tegomer V-Si 2250: diacryloxypolydimethylsiloxane (Evonik)
- Irgacure 819: bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (BASF or Ciba Specialty Chemicals)
- Irgacure 1870: blend of bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphineoxide and 1-hydroxy-cyclohexyl-phenyl-ketone (BASF or Ciba Specialty Chemicals)
- AIBN: azobisisobutyronitrile
- Te-Bu: ethyl 2-methyl-2-(butyltellanyl)propanoate
- TEMPO: 2,6-tetramethylpiperidine N-oxide
- TERP: organotellurium mediated living radical polymerization
- mPDMS: monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane (800-1000 MW) (Gelest)
- ac-PDMS: bis-3-acryloxy-2-hydroxypropyloxypropyl polydimethylsiloxane
- HO-mPDMS: mono-(2-hydroxy-3-methacryloxypropyl)-propyl ether terminated mono-n-butyl terminated polydimethylsiloxane (400-1000 MW) (Ortec or DSM-Polymer Technology Group)
- TRIS: 3-methacryloxypropyl tris(trimethylsiloxy)silane
- ac-TRIS: 3-acryloxypropyl tris(trimethylsiloxy)silane
- SiMAA: 2-propenoic acid, 2-methyl-2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propoxy]propyl ester (Toray)
- SA2: N-(2,3-dihydroxylpropyl)-N-(3-tetra(dimethylsiloxy)-dimethylbutylsilane)propyl) acrylamide
- mPEG 950 : polyethylene glycol mono-methacrylate (Aldrich)
- D3O: 3,7-dimethyl-3-octanol (Vigon)
- TAM: t-amyl alcohol (BASF)
- 3E3P: 3-ethyl 3-pentanol
- TPME: tripropylene glycol mono-methyl ether
- DA: decanoic acid
- DI water: deionized water
- MeOH: methanol
- IPA: isopropyl alcohol
- Norbloc: 2-(2'-hydroxy-5-methacrylyloxyethylphenyl)-2H-benzotriazole (Janssen)
- P2 Poly[DMA-NVP]: Copolymer of DMA-NVP, MW = 195 kDa by SEC-MALS, made according to Preparation 2
- P3 Poly[DMA-NVP]: Copolymer of DMA-NVP, Mw (MALS) = 304 kDa, made according to Preparation 3
- PP: polypropylene which is the homopolymer of propylene
- TT: Tuftec which is a hydrogenated styrene butadiene block copolymer (Asahi Kasei Chemicals)
- Z: Zeonor which is a polycycloolefin thermoplastic polymer (Nippon Zeon Co Ltd)
380 mL (3.48 mol) of distilled N-vinyl-N-methyl acetamide and 187 mg (1.14 mmol) of azobisisobutyronitrile were added to a 3-neck round bottom flask fitted with reflux condenser, magnetic stirring bar and thermocouple and purged of oxygen gas for 2 hours by bubbling nitrogen gas through the reaction mixture. Then, the reaction mixture was heated at 75°C for 24 hours during which time the reaction mixture solidified. The reaction product was quenched in air and isolated by work-up procedure 1 or work-up procedure 2. Work-up Procedure 1: The reaction product was dissolved in 800 mL of methylene chloride at 40°C and cooled to room temperature. The solution was poured into 2L of cold diethyl ether with manual stirring to afford a white solid after decanting off the solvents. The solid product was air dried followed by vacuum drying overnight at 50°C. The precipitated product was ground into a fine white powder and vacuum dried overnight at 50°C (85% yield). Work-up Procedure 2: The reaction product was dissolved in water and dialyzed extensively in dialysis membrane tubing (Spectra Pore MWCO 3500) and freeze dried (LABCONCO, Freezone® Triad™ freeze dry system, Model # 7400030) or spray dried (BUCHI mini spray dryer, Model # B-290). The molecular weight was determined by Size Exclusion Chromatography with Multi-Angle Light Scattering (SEC-MALS). The SEC-MALS setup employed methanol (with 10 mM LiBr) as the mobile phase at a flow rate of 0.6 mL/min at 50 °C. Three Tosoh Biosciences TSK-gel columns in series were used [SuperAW3000 4 um, 6.0 mm ID × 15 cm (PEO/DMF Exclusion Limit = 60,000 g/mole), SuperAW4000 6 um, 6.0 mm ID × 15 cm (PEO/DMF Exclusion Limit = 400,000 g/mole) and a SuperAW5000 7 um, 6.0 mm ID × 15 cm (PEO/DMF Exclusion Limit = 4,000,000 g/mole)] with an online Agilent 1200 UV/VIS diode array detector, a Wyatt Optilab rEX interferometric refractometer, and a Wyatt mini-DAWN Treos multiangle laser scattering (MALS) detector (λ=658nm). A dη/dc value of 0.1829 mL/g at 30 °C (λ=658 nm) was used for absolute molecular weight determination. Absolute molecular weights and polydispersity data were calculated using the Wyatt ASTRA 6.1.1.17 SEC/LS software package. The weight average molecular weight typically varied from about 500 kDa to about 700 kDa, but can be controlled by the reaction conditions and isolation procedures. The polydispersity varied from about 1.8 to about 2.8 among the samples.
12 milligrams (0.073 mmol) AIBN were dissolved in 200 mL MeOH in a 500 mL three necked round bottom flask equipped with a reflux condenser and pressure balanced addition funnel and containing a magnetic stirring bar. 42 grams (424 mmol) DMA and 47.09 grams (424 mmol) NVP were dissolved in 100 mL MeOH and added into the addition funnel. The solutions in both the round bottom flask and the addition funnel were purged with nitrogen gas for 30 minutes. Then, 26 milligrams (0.1 mmol) of Te-Bu were added into the round bottom flask, and heating of the round bottom flask to reflux (about 65°C) commenced. Slow dropwise addition of the monomer solution also started when heating commenced. The monomer addition occurred over 7.5 hours. The reaction mixture was then allowed to cool down to room temperature. The MeOH was removed by rotary evaporation. The crude product was re-dissolved in MeOH and precipitated into hexanes three times. The copolymer was vacuum dried at 50°C.
12 milligrams (0.073 mmol) AIBN were dissolved in 200 mL MeOH in a 500 mL three necked round bottom flask equipped with a reflux condenser and pressure balanced addition funnel and containing a magnetic stirring bar. 42 grams (424 mmol) DMA and 47.09 grams (424 mmol) NVP were dissolved in 100 mL MeOH and added into the addition funnel. The solutions in both the round bottom flask and the addition funnel were purged with nitrogen gas for 60 minutes. Then, 26 milligrams (0.1 mmol) of Te-Bu were added into the round bottom flask, and heating of the round bottom flask to reflux (about 65°C) commenced. Slow dropwise addition of the monomer solution also started when heating commenced. The monomer addition occurred over 4 hours. The reaction mixture was then refluxed for 20 hours thereafter 45 milligrams (0.29 mmol) TEMPO were added and the reaction mixture refluxed for another 5 hours. The reaction mixture was then allowed to cool down to room temperature. The reaction mixture was concentrated by rotary evaporation, and the crude product isolated by precipitation into diethyl ether. After decanting off the supernatant liquid, the crude product was re-dissolved in methylene chloride and precipitated into diethyl ether three times. The copolymer was vacuum dried at 70°C.
26 milligrams (0.16 mmol) AIBN, 20 grams (202 mmol) DMA and 5 grams (22 mmol) CBT were dissolved in 200 mL 50% (v/v) aqueous MeOH in a 500 mL round bottom flask equipped with a reflux condenser and containing a magnetic stirring bar. 41 milligrams (0.16 mmol) of Te-Bu were dissolved in 50 mL 50% (v/v) aqueous MeOH. Both solutions were purged with nitrogen gas for 30 minutes. Then, the Te-Bu solution was added to the round bottom flask and heated to reflux (about 62°C) for 12 hours. The reaction mixture was allowed to cool down to room temperature. The aqueous MeOH was removed by rotary evaporation. The crude product was dissolved in 500 mL acetone and precipitated by slowing adding 250 mL of hexane with stirring. After decanting off the supernatant liquid, the copolymer was vacuum dried at 62-68°C. Copolymer designated as Poly[DMA-CBT].
Each reactive mixture was formed by mixing the reactive components listed in Table 2, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 55-60°C, and the lenses were cured from the top for 20 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays. The weight ratio of OH-mPDMS, n=4 to mPDMS 1000, n=10 was 1.7. The molar ratio of OH-mPDMS, n=4 to mPDMS 1000, n=10 was 2.8.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 50% IPA for about one or two hours, followed by washing with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 3.
The wettability of NVP based silicone hydrogels without a polymeric wetting agent was reduced by small amounts of DMA in the reactive mixture. At 2.5 wt% DMA and above, the advancing contact angle increased to 107° (59° increase) compared to formulations without DMA (Comparative Example 6, with a DCA of 48°).
Each reactive mixture was formed by mixing the reactive components listed in Table 4, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 55-60°C, and the lenses were cured from the top for 20 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 50% IPA for about one or two hours, followed by washing with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 5.
These comparative Examples confirm that as little as about 2 wt% DMA in silicone hydrogel formulations containing greater than about 40 wt% NVP degrade wettability.
Each reactive mixture was formed by mixing the reactive components listed in Table 6, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 20 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 7. The homogeneity of the reactive mixtures improved as the amount of OH-mPDMS n=4 increased. Only lenses from Example 3 were suitable for testing, and their wettability was limited (91°) despite the presence poly[DMA-NVP] in the formulation at 2wt%.
Each reactive mixture was formed by mixing the reactive components listed in Table 8, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of a 90:10 (w/w) Z:PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 20 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The lenses of Examples 4 and 5 were hazy (subjectively observed), and were not further analyzed. The physical and mechanical properties of the sterile lenses were measured and listed in Table 9.
Example 8 had 12 wt% DMA/NVP copolymer and displayed a very desirable contact angle (53° advancing DCA) and haze (12%). Examples 6-8 had good haze values. Comparing Example 6 to Example 7 shows that decreasing the concentration of acyclic polyamide improves both haze and contact angle, suggesting that a desirable balance of properties could be achieved by maintaining a ratio of first to second silicone-containing component of 1.2, and decreasing the concentration of acyclic polyamide. Example 8 had a ratio of first to second silicone-containing component of 0.87, and showed improved haze and contact angle compared to Example 7. Thus, properties may also be balanced by maintaining the concentration of the acyclic polyamide, and decreasing the ratio first to second silicone-containing component to within the recited ranges.
Each reactive mixture was formed by mixing the reactive components listed in Table 10, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP or a blend of 90:10 (w/w) Z:PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 20 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 11.
Copolymer P2 had a molecular weight (Mw) of 195kD and copolymer P3 had a Mw of 305 KDa. Examples 9-11 all displayed good haze and contact angle, confirming that copolymeric wetting agents having molecular weights above about 190 kDa can provide desirable wettability and haze.
Each reactive mixture was formed by mixing the reactive components listed in Table 12, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of a blend of 90:10 (w/w) Z:PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 15 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by heating about 64 lenses in about one liter of DI water at 75°C for about 30-60 minutes, followed by washing two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 13.
Examples 12-15 all displayed desirable haze and contact angles. As the molecular weight (Mw) of the PVMA increased, the contact angle decreased, with Examples 14 (Mw of 628 kD) and 15 (Mw of 1600 kD) displaying improved wettability and decreased hysteresis compared to Example 13.
Each reactive mixture was formed by mixing the reactive components listed in Table 14, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 25 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 15.
Examples 16 and 17 contain a mixture of PVMA (6% 628kD and 6% 1600 kD Mw). Examples 19 and 20 were made from similar formulations, but with 12% of PVMA having a Mw of 628 kD. Examples 16 and 17, with the mixture including higher molecular weight PVMA displayed lower contact angles.
Each reactive mixture was formed by mixing the reactive components listed in Table 16, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 15-25 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 17.
The concentration of DMA in the reactive mixture was increased from 0 wt% (Example 21) to 4.1 wt% (Example 24), and the advancing contact angle remained below about 50°. This is in contrast to Comparative Examples 6-17, which showed that in NVP formulations without a combination of hydroxyl-substituted polydialkylsiloxanes, the inclusion of as little as about 2 wt% DMA increased contact angle above about 80°. Examples 21 -24 also show lipid uptake of about 6 µg/lens, which is desirably low. Commercially available lenses containing PVP display lipid uptake values of about 10 µg/lens.
Each reactive mixture was formed by mixing the reactive components listed in Table 18, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 25 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 19.
Lenses made from PVMA 628 kDa and mixtures DMA and NVP exhibited very low lipid (less than 7 µg/lens) and PQ1 uptake (less than 5%) as well as an excellent balance of physical and mechanical properties. The concentration of DMA in the reactive mixture was varied from about 5 wt% (Example 29) to about 8% (Example 25), and the advancing contact angle remained below about 60°, and in Examples 25, 27-29, below about 10°.
Each reactive mixture was formed by mixing the reactive components listed in Table 20, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC. The BC was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. Examples 30-32 used FC made of a 90:10 (w/w) blend of Z:TT and BC made of PP; examples 33-38 used FC made of Z and BC made of a 55:45 (w/w) blend of Z:PP. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 25 minutes using TLO3 lights having intensity of 4-5 mW/cm2 for Examples 30-32 and 3-4 mW/cm2 for Examples 33-38. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 21.
Lenses made from PVMA 628 kDa and mixtures DMA and NVP exhibited surprisingly excellent biometrics, including lipid uptake of about 10 µg/lens or less and PQ1 uptake less than about 10%, and moderate lysozyme uptake, as well as an excellent balance of physical and mechanical properties.
Each reactive mixture was formed by mixing the reactive components listed in Table 22, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of 90:10 (w/w) Z:TT. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 12 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 23.
Lysozyme uptake and PQ1 uptake increased with MAA content.
Example 41 was repeated, except that the ratio of the hydroxyl-containing silicone components was varied, as shown in Table 24. Example 44 is the same lens as Example 41, with only the lysozyme uptake test repeated. Each reactive mixture was formed by mixing the reactive components listed in Table 24, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 20 minutes using TLO3 lights having intensity of 3-4 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 25.
All lenses showed a desirable balance of mechanical and biometric properties.
Each reactive mixture was formed by mixing the reactive components listed in Table 26, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 25 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 27.
Lenses containing an ammonium chloride salt (Q-Salt) displayed greatly reduced lysozyme uptake, but a good balance of mechanical properties and low PQ-1 and lipid uptake. This example shows that cationic components can be added, without negatively impacting compatibility (as shown by the 18% haze) and while maintaining a desirable balance of properties.
Each reactive mixture was formed by mixing the reactive components listed in Table 28, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 25 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 29.
The Poly[DMA-co-CBT], is a random copolymer of DMA and 20 wt% (10 mol%) zwitterionic monomer carboxybetaine. Carboxybetaine is highly hydrophilic internal salt which is generally poorly compatible with silicone hydrogel reactive mixtures. It was surprising that 5wt% of this copolymer could be incorporated into silicone hydrogels formulations displaying only 30% haze. Lenses containing zwitterionic internal wetting agent showed increased lysozyme and PQ1 uptake.
A series of lenses were made from reactive mixtures with varying formulation components, including hydrophilic monomer, hydroxyl-containing silicone component, types and amount of crosslinker and amounts of ionic monomer. Each reactive mixture was formed by mixing the reactive components listed in Table 30, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 12 minutes using TLO3 lights having intensity of 4-5 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 31.
All lenses showed a desirable combination of properties. Also, comparing Examples 61-63 to the lenses made in
Each reactive mixture was formed by mixing the reactive components listed in Table 32, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of a 55:45 (w/w) blend of Z and PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C. The lenses of Examples 64 and 66-68 were cured from the top for 20 minutes using 420 nm and 435 nm LED lights, respectively, having intensity of 4 mW/cm2. Example 65 was cured using TLO3 bulbs at 5 mW/cm2, for 15 minutes. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 33.
Lenses prepared using mixtures of NVP and DMA together with mixtures of OH-mPDMS and mixtures of PVMA and PVP as the internal wetting agents showed an excellent balance of biometric properties including moderate lysozyme, PQ1, and lipid uptake.
Each reactive mixture was formed by mixing the reactive components listed in Table 34, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of a 55:45 (w/w) blend of Z and PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 20 minutes using 435 nm LED lights having intensity of 4 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 35.
This series of Examples shows that lenses having very low lipid uptake values (less than about 5 ug/lens, and less than 3 ug/lens) may be prepared using a combination of acyclic polyamide and PVP. All lenses had a desirable balance of both biometric, physical and mechanical properties.
Each reactive mixture was formed by mixing the reactive components listed in Table 36, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of a 55:45 (w/w) blend of Z and PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 62-65°C, and the lenses were cured from the top for 20 minutes using 435 nm LED lights having intensity of 4 mW/cm2. The light source was about six inches above the trays.
The lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with 25% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted about 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 37.
Lenses prepared using mixtures of NVP and DMA together with mixtures of OH-mPDMS and mixtures of PVMA and PVP as the internal wetting agents showed an excellent balance of biometric properties including moderate lysozyme, PQ1, and lipid uptake, except when mPDMS was also included in the reactive mixture.
Lenses were made from the formulation listed in Example 82 of Table 38, below, using the procedures described in Examples 74-77. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses of Example 82 were measured and listed in Table 39.
Each reactive mixture was formed by mixing the reactive components listed in Table 40, filtering through a 3 µm filter using a heated or unheated stainless steel or glass syringe, and then degassed by applying vacuum at ambient temperature for about 10 minutes. In a glove box with a nitrogen gas atmosphere and less than 0.1 percent oxygen gas, about 75-100 µL of the reactive mixture were dosed using an Eppendorf pipet at room temperature into the FC made of Zeonor. The BC made of a 55:45 (w/w) blend of Z and PP was then placed onto the FC. The molds were equilibrated for a minimum of twelve hours in the glove box prior to dosing. The plate was transferred into an adjacent glove box maintained at 60-65°C, and the lenses were cured from the top. Examples 83 and 84 were cured for 20 minutes using 435 nm LED lights having intensity of 4 mW/cm2. Examples 85-90 were cured for 15 minutes using TLO3 lights having intensity of 5 mW/cm2. The light source was about six inches above the trays.
On the other hand, examples 91-93 were cured using 435 nm LED lights from the top and bottom first using an intensity of 1 mW/cm2 for 2 minutes and second using an intensity of 2.5 mW/cm2 for 6 minutes. Examples 91-93 also used a 90:10 (w/w) Z:TT blend FC and a 90: 10 (w/w) Z:PP blend BC. The reaction temperature was 65°C, and the oxygen gas concentration was 0.1 percent in the glove box.
For Examples 83-90, the lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 40% IPA for about one or two hours, followed by washing two times with 40% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted at least 30 minutes. For Examples 91-93, the lenses were manually de-molded with most lenses adhering to the FC and released by suspending the 64 lenses in about one liter of 70% IPA for about one or two hours, followed by washing two times with 70% IPA, two times with DI, and finally two times with borate buffered packaging solution. Each washing step lasted at least 30 minutes. A person of ordinary skill recognizes that the exact lens release process can be varied depending on the lens formulation and mold materials, regarding the concentrations of the aqueous isopropanol solutions, the number of washings with each solvent, and the duration of each step. The purpose of the lens release process is to release all of the lenses without defects and transition from diluent swollen networks to the packaging solution swollen hydrogels. The lenses were transferred into vials and subsequently sterilized by autoclaving at 122°C for 30 minutes. The physical and mechanical properties of the sterile lenses were measured and listed in Table 41.