Technical Field
[0001] The present invention relates to novel chemical compounds having immunomodulatory
activity and synthetic intermediates useful for the preparation of the novel compounds,
and in particular to macrolide immunomodulators. More particularly, the invention
relates to semisynthetic analogs of rapamycin, means for their preparation, pharmaceutical
compositions containing such compounds, and methods of treatment employing the same.
Background of The Invention
[0002] The compound cyclosporine (cyclosporin A) has found wide use since its introduction
in the fields of organ transplantation and immunomodulation, and has brought about
a significant increase in the success rate for transplantation procedures. Recently,
several classes of macrocyclic compounds having potent immunomodulatory activity have
been discovered. Okuhara
et al., in European Patent Application No. 184,162, published June 11, 1986, disclose a
number of macrocyclic compounds isolated from the genus
Streptomyces, including the immunosuppressant FK-506, a 23-membered macrocyclic lactone, which
was isolated from a strain of
S. tsukubaensis.
[0003] Other related natural products, such as FR-900520 and FR-900523, which differ from
FK-506 in their alkyl substituent at C-21, have been isolated from
S. hygroscopicus yakushimnaensis. Another analog, FR-900525, produced by
S. tsukubaensis, differs from FK-506 in the replacement of a pipecolic acid moiety with a proline
group. Unsatisfactory side-effects associated with cyclosporine and FK-506 such as
nephrotoxicity, have led to a continued search for immunosuppressant compounds having
improved efficacy and safety, including an immunosupressive agent which is effective
topically, but ineffective systemically (U.S. Patent No. 5,457,111).
[0004] Rapamycin is a macrocyclic triene antibiotic produced by
Streptomyces hygroscopicus, which was found to have antifungal activity, particularly against
Candida albicans, both in vitro and in vivo (C. Vezina et al.,
J. Antibiot. 1975, 28, 721; S. N. Sehgal et al.,
J. Antibiot. 1975,
28, 727; H. A. Baker et al.,
J. Antibiot. 1978,
31, 539; U.S. Patent No. 3,929,992; and U.S. Patent No. 3,993,749).

[0005] Rapamycin alone (U.S. Patent No. 4,885,171) or in combination with picibanil (U.S.
Patent No. 4,401,653) has been shown to have antitumor activity. In 1977, rapamycin
was also shown to be effective as an immunosuppressant in the experimental allergic
encephalomyelitis model, a model for multiple sclerosis; in the adjuvant arthritis
model, a model for rheumatoid arthritis; and was shown to effectively inhibit the
formation of IgE-like antibodies (R. Martel et al.,
Can. J. Physiol. Pharmacol., 1977,
55, 48).
[0006] The immunosuppressive effects of rapamycin have also been disclosed in
FASEB, 1989,
3, 3411 as has its ability to prolong survival time of organ grafts in histoincompatible
rodents (R. Morris,
Med. Sci. Res., 1989,
17, 877). The ability of rapamycin to inhibit T-cell activation was disclosed by M.
Strauch (
FASEB, 1989,
3, 3411). These and other biological effects of rapamycin are reviewed in
Transplantation Reviews, 1992,
6, 39-87.
[0007] Mono-ester and di-ester derivatives of rapamycin (esterification at positions 31
and 42) have been shown to be useful as antifungal agents (U.S. Patent No. 4,316,885)
and as water soluble prodrugs of rapamycin (U.S. Patent No. 4,650,803).
[0008] Fermentation and purification of rapamycin and 30-demethoxy rapamycin have been described
in the literature (C. Vezina et al.
J. Antibiot. (Tokyo), 1975,
28 (10), 721; S. N. Sehgal et al.,
J. Antibiot. (Tokyo), 1975,
28(10), 727; 1983,
36(4), 351; N. L. Pavia et al.,
J. Natural Products, 1991,
54(1), 167-177).
[0009] Numerous chemical modifications of rapamycin have been attempted. These include the
preparation of mono- and di-ester derivatives of rapamycin (WO 92/05179), 27-oximes
of rapamycin (EP0 467606); 42-oxo analog of rapamycin (U.S. Patent No. 5,023,262);
bicyclic rapamycins (U.S. Patent No. 5,120,725); rapamycin dimers (U.S. Patent No.
5,120,727); silyl ethers of rapamycin (U.S. Patent No. 5,120,842); and arylsulfonates
and sulfamates (U.S. Patent No. 5,177, 203). WO 95 14023 discloses macrolide compounds
which are semisynthetic analogs of rapamycin having immunomodulatory activity.
WO 98 09970 relates to alkylated rapamycin derivatives which possess immunosuppressive
and/or anti tumor and/or antiinflammatory activity in vivo and/or inhibit thymocyte
proliferation in vitro.
WO 98 09972 relates to rapamycin derivatives with unnatural stereochemistries which
possess immunosuppressive and/or anti tumor and/or antiinflammatory activity in vivo
and/or inhibit thymocyte proliferation in vitro.
Rapamycin was recently synthesized in its naturally occuring enantiomeric form (K.
C. Nicolaou et al.,
J. Am. Chem. Soc., 1993,
115, 4419-4420; S. L. Schreiber,
J. Am. Chem. Soc., 1993,
115, 7906-7907: S. J. Danishefsky,
J. Am. Chem. Soc., 1993,
115, 9345-9346.
[0010] It has been known that rapamycin, like FK-506. binds to FKBP-12 (Siekierka, J. J.;
Hung, S. H. Y.: Poe, M.: Lin, C. S.; Sigal. N. H.
Nature,
1989, 341, 755-757; Harding, M. W.; Galat. A.; Uehling, D. E.; Schreiber, S. L.
Nature 1989, 341, 758-760; Dumont, F. J.; Melino, M. R.; Staruch. M. J.; Koprak. S. L.; Fischer, P.
A.; Sigal, N. H.
J. Immunol.
1990, 144, 1418-1424; Bierer, B. E.; Schreiber, S. L.; Burakoff, S. J.
Eur. J. Immunol.
1991,
21, 439-445; Fretz, H.; Albers, M. W.; Galat, A.; Standaert, R. F.; Lane, W. S.: Burakoff,
S. J.; Bierer, B. E.; Schreiber, S. L.
J. Am. Chem. Soc. 1991, 113, 1409-1411). Recently it has been discovered that the rapamycin/FKBP-12 complex binds
to yet another protein, which is distinct from calcineurin, the protein that the FK-506/FKBP-12
complex inhibits (Brown, E. J.; Albers, M. W.: Shin, T. B.; Ichikawa, K.; Keith, C.
T.; Lane. W. S.; Schreiber. S. L.
Nature 1994, 369, 756-758; Sabatini, D. M.; Erdjument-Bromage, H.; Lui, M.; Tempest. P.: Snyder, S.
H.
Cell, 1994, 78, 35-43).
[0011] Although some of these modified compounds exhibit immunosuppressive activity, the
need remains for macrocyclic immunosuppressants which do not have the serious side
effects frequently associated with immunosuppressant therapy due, in part, to the
extended half lives of the immunosupressants. Accordingly, one object of this invention
is to provide novel semisynthetic macrolides which possess the desired immunomodulatory
activity but which may be found to minimize unwanted side effects due to their shortened
half-life.
Brief Description of the Figure
[0012] Figure 1 shows blood concentrations ± SEM (n=3) of tetrazole-containing rapamycin
analogs dosed in monkey.
Summary of The Invention
[0013] In one aspect of the present invention are disclosed compounds represented by the
structural formula:

or a pharmaceutically acceptible salt or ester thereof.
[0014] Another object of the present invention is to provide synthetic processes for the
preparation of such compounds from starting materials obtained by fermentation, as
well as chemical intermediates useful in such synthetic processes.
[0015] A further object of the invention is to provide pharmaceutical compositions containing,
as an active ingredient, at least one of the above compounds.
[0016] Yet another object of the invention is to provide a method of treating a variety
of disease states, including restenosis, post-transplant tissue rejection, immune
and autoimmune dysfunction, fungal growth, and cancer.
Detailed Description of the Invention
Definition of Terms
[0017] The term "prodrug," refers to compounds which are rapidly transformed
in vivo to the parent compound of the above formula, for example, by hydrolysis in blood.
A thorough discussion is provided in T. Higuchi and V. Stella, "Prodrugs as Novel
Delivery Systems," Vol. 14 of the A.C.S. Symposium Series, and in Edward B. Roche,
ed., "Bioreversible Carriers in Drug Design," American Pharmaceutical Association
and Pergamon Press, 1987, both of which are hereby incorporated by reference.
[0018] The term "pharmaceutically acceptable prodrugs," refers to those prodrugs of the
compounds of the present invention which are, within the scope of sound medical judgement,
suitable for use in contact with the tissues of humans and lower mammals without undue
toxicity, irritation, and allergic response, are commensurate with a reasonable benefit/risk
ratio, and are effective for their intended use, as well as the zwitterionic forms,
where possible, of the compounds of the invention. Particularly preferred pharmaceutically
acceptable prodrugs are prodrug esters of the C-31 hydroxyl group of compounds of
this invention.
[0019] The term "esters," as used herein, refers to any of several ester-forming groups
that are hydrolyzed under physiological conditions. Examples of prodrug ester groups
include acetyl, ethanoyl, pivaloyl, pivaloyloxymethyl, acetoxymethyl, phthalidyl,
methoxymethyl, indanyl, and the like, as well as ester groups derived from the coupling
of naturally or unnaturally-occuring amino acids to the C-31 hydroxyl group of compounds
of this invention.
Embodiments
[0020] In one embodiment of the invention is a compound of formula

In another embodiment of the invention is a compound of formula

Preparation of Compounds of this Invention
[0021] The compounds and processes of the present invention will be better understood in
connection with the following synthetic schemes which illustrate the methods by which
the compounds of the invention may be prepared.
[0022] The compounds of this invention may be prepared by a variety of synthetic routes.
A representative procedure is shown in Scheme 1.

[0023] As shown in Scheme 1, conversion of the C-42 hydroxyl of rapamycin to a trifluoromethanesulfonate
or fluorosulfonate leaving group provided A. Displacement of the leaving group with
tetrazole in the presence of a hindered, non-nucleophilic base, such as 2,6-lutidine,
or, preferably, diisopropylethyl amine provided epimers B and C, which were separated
and purified by flash column chromatography.
Synthetic Methods
[0024] The foregoing may be better understood by reference to the following examples which
illustrate the methods by which the compounds of the invention may be prepared.
Example 1
42-Epi-(tetrazolyl)-rapamycin (less polar isomer)
Example 1A
[0025] A solution of rapamycin (100 mg, 0.11 mmol) in dichloromethane (0.6 mL) at -78 °C
under a nitrogen atmosphere was treated sequentially with 2,6-lutidine (53 uL, 0.46
mmol, 4.3 eq.) and trifluoromethanesulfonic anhydride (37 uL, 0.22 mmol), and stirred
thereafter for 15 minutes, warmed to room temperature and eluted through a pad of
silica gel (6 mL) with diethyl ether. Fractions containing the triflate were pooled
and concentrated to provide the designated compound as an amber foam.
Example 1B
42-Epi-(tetrazolyl)-rapamycin (less polar isomer)
[0026] A solution of Example 1A in isopropyl acetate (0.3 mL) was treated sequentially with
diisopropylethylamine (87 µL. 0.5 mmol) and IH-tetrazole (35 mg. 0.5 mmol), and thereafter
stirred for 18 hours. This mixture was partitioned between water (10 mL) and ether
(10 mL). The organics were washed with brine (10 mL) and dried (Na
2SO
4). Concentration of the organics provided a sticky yellow solid which was purified
by chromatography on silica gel (3.5 g, 70-230 mesh) eluting with hexane (10 mL),
hexane:ether (4:1(10 mL), 3:1(10 mL), 2:1(10 mL), 1:1(10 mL)), ether (30 mL), hexane:acetone
(1:1(30mL)). One of the isomers was collected in the ether fractions. MS (ESI) m/e
966 (M)
-;
Example 2
42-Epi-(tetrazolyl)-rapamycin (more polar isomer)
Example 2A
42-Epi-(tetrazolyl)-rapamycin (more polar isomer)
[0027] Collection of the slower moving band from the chromatography column using the hexane:acetone
(1:1) mobile phase in Example 1B provided the designated compound. MS (ESI) m/e 966
(M)
-.
In vitro Assay of Biological Activity
[0028] The immunosuppressant activity of the compounds of the present invention was determined
using the human mixed lymphocyte reaction (MLR) assay described by Kino, T.
et al. in
Transplantation Proceedings, XIX(5):36-39. Suppl. 6 (
1987). The results of the assay demonstrate that the compounds of the invention are effective
immunomodulators at nanomolar concentrations, as shown in Table 1.
Table 1
| Example |
Human MLR IC50 ± S.E.M.(nM) |
| Rapamycin |
0.91 ± 0.36 |
| Example 1 |
1.70 ± 0.48 |
| Example 2 |
0.66 ± 0.19 |
[0029] The pharmacokinetic behaviors of Example 1 and Example 2 were characterized following
a single 2.5 mg/kg intravenous dose in cynomolgus monkey (n=3 per group). Each compound
was prepared as 2.5 mg/mL solution in a 20% ethanol:30% propylene glycol:2% cremophor
EL:48% dextrose 5% in water vehicle. The 1 mL/kg intravenous dose was administered
as a slow bolus (~1-2 minutes) in a saphenous vein of the monkeys. Blood samples were
obtained from a femoral artery or vein of each animal prior to dosing and 0.1 (IV
only), 0.25, 0.5, 1, 1.5, 2, 4, 6, 9, 12, 24, and 30 hours after dosing. The EDTA
preserved samples were thoroughly mixed and extracted for subsequent analysis.
[0030] An aliquot of blood (1.0 mL) was hemolyzed with 20% methanol in water (0.5 ml) containing
an internal standard. The hemolyzed samples were extracted with a mixture of ethyl
acetate and hexane (1:1 (v/v), 6.0 mL). The organic layer was evaporated to dryness
with a stream of nitrogen at room temperature. Samples were reconstituted in methanol:
water (1:1, 150 µL). The title compounds (50 µL injection) were separated from contaminants
using reverse phase HPLC with UV detection. Samples were kept cool (4 °C) through
the run. All samples from each study were analyzed as a single batch on the HPLC.
[0031] Area under the curve (AUC) measurements of Example 1, Example 2 and the internal
standard were determined using the Sciex MacQuan™ software. Calibration curves were
derived from peak area ratio (parent drug/internal standard) of the spiked blood standards
using least squares linear regression of the ratio versus the theoretical concentration.
The methods were linear for both compounds over the range of the standard curve (correlation
> 0.99) with an estimated quantitation limit of 0.1 ng/mL. The maximum blood concentration
(C
MAX) and the time to reach the maximum blood concentration (T
MAX) were read directly from the observed blood concentration-time data. The blood concentration
data were submitted to multi-exponential curve fitting using CSTRIP to obtain estimates
of pharmacokinetic parameters. The estimated parameters were further defined using
NONLIN84. The area under the blood concentration-time curve from 0 to t hours (last
measurable blood concentration time point) after dosing (AUC
0-t) was calculated using the linear trapeziodal rule for the blood-time profiles. The
residual area extrapolated to infinity, determined as the final measured blood concentration
(C
t) divided by the terminal elimination rate constant (β), and added to AUC
0-t to produce the total area under the curve (AUC
0- ).
[0032] As shown in Figure 1 and Table 2, both Example 1 and Example 2 had a suprisingly
substantially shorter terminal elimination half-life (t
1/2) when compared to rapamycin.
Table 2
| Compound |
AUC ng·hr/mL |
t1/2 (hours) |
| Rapamycin |
6.87 |
16.7 |
| Example 1 |
2.35 |
5.0 |
| Example 2 |
2.38 |
6.9 |
Methods of Treatment
[0033] The compounds of the invention, including those specified in the examples, possess
immunomodulatory activity in mammals (especially humans). As immunosuppressants, the
compounds of the present invention are useful for the treatment and prevention of
immune-mediated diseases such as the resistance by transplantation of organs or tissue
such as heart, kidney, liver, medulla ossium, skin, cornea, lung, pancreas, intestinum
tenue, limb, muscle, nerves, duodenum, small-bowel, pancreatic-islet-cell; graft-versus-host
diseases brought about by medulla ossium transplantation; autoimmune diseases such
as rheumatoid arthritis, systemic lupus erythematosus, Hashimoto's thyroiditis, multiple
sclerosis, myasthenia gravis, type I diabetes, uveitis, allergic encephalomyelitis,
glomerulonephritis. Further uses include the treatment and prophylaxis of inflammatory
and hyperproliferative skin diseases and cutaneous manifestations of immunologically-mediated
illnesses, such as psoriasis, atopic dermatitis, contact dermatitis and further eczematous
dermatitises, seborrhoeis dermatitis, lichen planus, pemphigus, bullous pemphigoid,
epidermolysis bullosa, urticaria, angioedemas, vasculitides, erythemas, cutaneous
eosinophilias, lupus erythematosus, acne and alopecia areata; various eye diseases
(autoimmune and otherwise) such as keratoconjunctivitis, vernal conjunctivitis, uveitis
associated with Behcet's disease, keratitis, herpetic keratitis, conical cornea, dystrophia
epithelialis corneae, corneal leukoma, and ocular pemphigus. In addition reversible
obstructive airway disease, which includes conditions such as asthma (for example,
bronchial asthma, allergic asthma, intrinsic asthma, extrinsic asthma and dust asthma),
particularly chronic or inveterate asthma (for example, late asthma and airway hyper-responsiveness),
bronchitis, allergic rhinitis, are targeted by compounds of this invention. Inflammation
of mucosa and blood vessels such as gastric ulcers, vascular damage caused by ischemic
diseases and thrombosis. Moreover, hyperproliferative vascular diseases such as intimal
smooth muscle cell hyperplasia, restenosis and vascular occlusion, particularly following
biologically- or mechanically-mediated vascular injury, could be treated or prevented
by the compounds of the invention. Other treatable conditions include but are not
limited to ischemic bowel diseases, inflammatory bowel diseases, necrotizing enterocolitis,
intestinal inflammations/allergies such as Coeliac diseases, proctitis, eosinophilic
gastroenteritis, mastocytosis, Crohn's disease and ulcerative colitis; nervous diseases
such as multiple myositis, Guillain-Barre syndrome. Meniere's disease, polyneuritis,
multiple neuritis, mononeuritis and radiculopathy: endocrine diseases such as hyperthyroidism
and Basedow's disease; hematic diseases such as pure red cell aplasia, aplastic anemia,
hypoplastic anemia, idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia,
agranulocytosis, pernicious anemia, megaloblastic anemia and anerythroplasia; bone
diseases such as osteoporosis; respiratory diseases such as sarcoidosis, fibroid lung
and idiopathic interstitial pneumonia; skin disease such as dermatomyositis, leukoderma
vulgaris, ichthyosis vulgaris, photoallergic sensitivity and cutaneous T cell lymphoma;
circulatory diseases such as arteriosclerosis, atherosclerosis, aortitis syndrome,
polyarteritis nodosa and myocardosis; collagen diseases such as scleroderma, Wegener's
granuloma and Sjogren's syndrome; adiposis; eosinophilic fasciitis; periodontal disease
such as lesions of gingiva, periodontium, alveolar bone and substantia ossea dentis;
nephrotic syndrome such as glomerulonephritis; male pattern aleopecia or alopecia
senilis by preventing epilation or providing hair germination and/or promoting hair
generation and hair growth; muscular dystrophy; Pyoderma and Sezary's syndrome; Addison's
disease; active oxygen-mediated diseases, as for example organ injury such as ischemia-reperfusion
injury of organs (such as heart, liver, kidney and digestive tract) which occurs upon
preservation, transplantation or ischemic disease (for example, thrombosis and cardiac
infarction); intestinal diseases such as endotoxin-shock, pseudomembranous colitis
and colitis caused by drug or radiation; renal diseases such as ischemic acute renal
insufficiency and chronic renal insufficiency; pulmonary diseases such as toxinosis
caused by lung-oxygen or drug (for example, paracort and bleomycins), lung cancer
and pulmonary emphysema; ocular diseases such as cataracta, siderosis, retinitis,
pigmentosa, senile macular degeneration, vitreal scarring and corneal alkali burn;
dermatitis such as erythema multiforme, linear IgA ballous dermatitis and cement dermatitis;
and others such as gingivitis, periodontitis, sepsis, pancreatitis, diseases caused
by environmental pollution (for example, air pollution), aging, carcinogenesis, metastasis
of carcinoma and hypobaropathy; diseases caused by histamine or leukotriene-C
4 release; Behcet's disease such as intestinal-, vasculo- or neuro-Behcet's disease,
and also Behcet's which affects the oral cavity, skin, eye, vulva, articulation, epididymis,
lung, kidney and so on. Furthermore, the compounds of the invention are useful for
the treatment and prevention of hepatic disease such as immunogenic diseases (for
example, chronic autoimmune liver diseases such as autoimmune hepatitis, primary biliary
cirrhosis and sclerosing cholangitis), partial liver resection, acute liver necrosis
(e.g. necrosis caused by toxin, viral hepatitis, shock or anoxia), B-virus hepatitis,
non-A/non-B hepatitis, cirrhosis (such as alcoholic cirrhosis) and hepatic failure
such as fulminant hepatic failure, late-onset hepatic failure and "acute-on-chronic"
liver failure (acute liver failure on chronic liver diseases), and moreover are useful
for various diseases because of their useful activity such as augmention of chemotherapeutic
effect, cytomegalovirus infection, particularly HCMV infection, anti-inflammatory
activity, sclerosing and fibrotic diseases such as nephrosis, scleroderma, pulmonary
fibrosis, arteriosclerosis, congestive heart failure, ventricular hypertrophy, post-surgical
adhesions and scarring, stroke, myocardial infarction and injury associated with ischemia
and reperfusion.
[0034] Additionally, compounds of the invention possess FK-506 antagonistic properties.
The compounds of the present invention may thus be used in the treatment of immunodepression
or a disorder involving immunodepression. Examples of disorders involving immunodepression
include AIDS, cancer, fungal infections, senile dementia, trauma (including wound
healing, surgery and shock) chronic bacterial infection, and certain central nervous
system disorders. The immunodepression to be treated may be caused by an overdose
of an immunosuppressive macrocyclic compound, for example derivatives of 12-(2-cyclohexyl-1-methylvinyl)-13,19,21,27-tetramethyl-11,28-dioxa-4-azatricyclo[22.3.1.0
4,9] octacos-18-ene such as FK-506 or rapamycin. The overdosing of such medicants by
patients is quite common upon their realizing that they have forgotten to take their
medication at the prescribed time and can lead to serious side effects.
[0035] The ability of the compounds of the invention to treat proliferative diseases can
be demonstrated according to the methods described in Bunchman ET and CA Brookshire,
Transplantation Proceed.
23 967-968 (1991); Yamagishi, et al., Biochem. Biophys. Res. Comm.
191 840-846 (1993); and Shichiri, et al., J. Clin. Invest.
87 1867-1871 (1991). Proliferative diseases include smooth muscle proliferation, systemic
sclerosis, cirrhosis of the liver, adult respiratory distress syndrome, idiopathic
cardiomyopathy, lupus erythematosus, diabetic retinopathy or other retinopathies,
psoriasis, scleroderma, prostatic hyperplasia, cardiac hyperplasia, restenosis following
arterial injury or other pathologic stenosis of blood vessels. In addition, these
compounds antagonize cellular responses to several growth factors, and therefore possess
antiangiogenic properties, making them useful agents to control or reverse the growth
of certain tumors, as well as fibrotic diseases of the lung, liver, and kidney.
[0036] Aqueous liquid compositions of the present invention are particularly useful for
the treatment and prevention of various diseases of the eye such as autoimmune diseases
(including, for example, conical cornea, keratitis, dysophia epithelialis corneae,
leukoma, Mooren's ulcer, sclevitis and Graves' ophthalmopathy) and rejection of corneal
transplantation.
[0037] When used in the above or other treatments, a therapeutically effective amount of
one of the compounds of the present invention may be employed in pure form or, where
such forms exist, in pharmaceutically acceptable salt, or ester form. Alternatively,
the compound may be administered as a pharmaceutical composition containing the compound
of interest in combination with one or more pharmaceutically acceptable excipients.
The phrase "therapeutically effective amount" of the compound of the invention means
a sufficient amount of the compound to treat disorders, at a reasonable benefit/risk
ratio applicable to any medical treatment. It will be understood, however, that the
total daily usage of the compounds and compositions of the present invention will
be decided by the attending physician within the scope of sound medical judgement.
The specific therapeutically effective dose level for any particular patient will
depend upon a variety of factors including the disorder being treated and the severity
of the disorder; activity of the specific compound employed; the specific composition
employed; the age, body weight, general health, sex and diet of the patient; the time
of administration, route of administration, and rate of excretion of the specific
compound employed; the duration of the treatment; drugs used in combination or coincidental
with the specific compound employed; and like factors well known in the medical arts.
For example, it is well within the skill of the art to start doses of the compound
at levels lower than required to achieve the desired therapeutic effect and to gradually
increase the dosage until the desired effect is achieved.
[0038] The total daily dose of the compounds of this invention administered to a human or
lower animal may range from about 0.01 to about 10 mg/kg/day. For purposes of oral
administration, more preferable doses may be in the range of from about 0.001 to about
3 mg/kg/day. If desired, the effective daily dose may be divided into multiple doses
for purposes of administration; consequently, single dose compositions may contain
such amounts or submultiples thereof to make up the daily dose. Topical adminstration
may involve doses ranging from 0.001 to 3% mg/kg/day, depending on the site of application.
Pharmaceutical Compositions
[0039] The pharmaceutical compositions of the present invention comprise a compound of the
invention and a pharmaceutically acceptable carrier or excipient, which may be administered
orally, rectally, parenterally, intracisternally, intravaginally, intraperitoneally,
topically (as by powders, ointments, drops or transdermal patch), bucally, or as an
oral or nasal spray. The phrase "pharmaceutically acceptable carrier" means a non-toxic
solid, semi-solid or liquid filler, diluent, encapsulating material or formulation
auxiliary of any type. The term "parenteral," as used herein, refers to modes of administration
which include intravenous, intramuscular, intraperitoneal, intrasternal, subcutaneous
and intraarticular injection and infusion.
[0040] Pharmaceutical compositions of this invention for parenteral injection comprise pharmaceutically
acceptable sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions
as well as sterile powders for reconstitution into sterile injectable solutions or
dispersions just prior to use. Examples of suitable aqueous and nonaqueous carriers,
diluents, solvents or vehicles include water, ethanol, polyols (such as glycerol,
propylene glycol, polyethylene glycol, carboxymethylcellulose and suitable mixtures
thereof, vegetable oils (such as olive oil), and injectable organic esters such as
ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating
materials such as lecithin, by the maintenance of the required particle size in the
case of dispersions, and by the use of surfactants.
[0041] These compositions may also contain adjuvants such as preservatives, wetting agents,
emulsifying agents, and dispersing agents. Prevention of the action of microorganisms
may be ensured by the inclusion of various antibacterial and antifungal agents, for
example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be
desirable to include isotonic agents such as sugars, sodium chloride, and the like,
Prolonged absorption of the injectable pharmaceutical form may be brought about by
the inclusion of agents which delay absorption such as aluminum monostearate and gelatin.
[0042] In some cases, in order to prolong the effect of the drug, it is desirable to slow
the absorption of the drug from subcutaneous or intramuscular injection. This may
be accomplished by the use of a liquid suspension of crystalline or amorphous material
with poor water solubility. The rate of absorption of the drug then depends upon its
rate of dissolution which, in turn, may depend upon crystal size and crystalline form.
Alternatively, delayed absorption of a parenterally administered drug form is accomplished
by dissolving or suspending the drug in an oil vehicle.
[0043] Injectable depot forms are made by forming microencapsule matrices of the drug in
biodegradable polymers such as polylactide-polyglycolide. Depending upon the ratio
of drug to polymer and the nature of the particular polymer employed, the rate of
drug release can be controlled. Examples of other biodegradable polymers include poly(orthoesters)
and poly(anhydrides) Depot injectable formulations are also prepared by entrapping
the drug in liposomes or microemulsions which are compatible with body tissues.
[0044] The injectable formulations can be sterilized, for example, by filtration through
a bacterial-retaining filter, or by incorporating sterilizing agents in the form of
sterile solid compositions which can be dissolved or dispersed in sterile water or
other sterile injectable medium just prior to use.
[0045] Solid dosage forms for oral administration include capsules, tablets, pills, powders,
and granules. In such solid dosage forms, the active compound is mixed with at least
one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate
or dicalcium phosphate and/or a) fillers or extenders such as starches, lactose, sucrose,
glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose,
alginates, gelatin, polyvinylpyrrolidone, sucrose, and acacia, c) humectants such
as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato
or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution
retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium
compounds, g) wetting agents such as, for example, cetyl alcohol and glycerol monostearate,
h) absorbents such as kaolin and bentonite clay, and i) lubricants such as talc, calcium
stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and
mixtures thereof. In the case of capsules, tablets and pills, the dosage form may
also comprise buffering agents.
[0046] Solid compositions of a similar type may also be employed as fillers in soft, semi-solid
and hard-filled gelatin capsules or liquid-filled capsules using such excipients as
lactose or milk sugar as well as high molecular weight polyethylene glycols.
[0047] The solid dosage forms of tablets, dragees, capsules, pills, and granules can be
prepared with coatings and shells such as enteric coatings and other coatings well
known in the pharmaceutical formulating art. They may optionally contain opacifying
agents and can also be of a composition that they release the active ingredient(s)
only, or preferentially, in a certain part of the intestinal tract, optionally, in
a delayed manner. Examples of embedding compositions which can be used include polymeric
substances and waxes.
[0048] The active compounds can also be in micro-encapsulated form, if appropriate, with
one or more of the above-mentioned excipients.
[0049] Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions,
solutions, suspensions, syrups and elixirs. In addition to the active compounds, the
liquid dosage forms may contain inert diluents commonly used in the art such as, for
example, water or other solvents, solubilizing agents and emulsifiers such as ethyl
alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl
benzoate, propylene glycol, 1,3-butylene glycol, dimethyl formamide, oils (in particular,
cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl
alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof.
[0050] Besides inert diluents, the oral compositions can also include adjuvants such as
wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming
agents.
[0051] Suspensions, in addition to the active compounds, may contain suspending agents as,
for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan
esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar,
and tragacanth, and mixtures thereof.
[0052] Topical administration includes administration to the skin or mucosa, including surfaces
of the lung and eye. Compositions for topical administration, including those for
inhalation, may be prepared as a dry powder which may be pressurized or non-pressurized.
In non-pressurized powder compositions, the active ingredient in finely divided form
may be used in admixture with a larger-sized pharmaceutically acceptable inert carrier
comprising particles having a size, for example, of up to 100 micrometers in diameter.
Suitable inert carriers include sugars such as lactose. Desirably, at least 95% by
weight of the particles of the active ingredient have an effective particle size in
the range of 0.01 to 10 micrometers. Compositions for topical use on the skin also
include oinments, creams, lotions, and gels.
[0053] Alternatively, the composition may be pressurized and contain a compressed gas, such
as nitrogen or a liquified gas propellant. The liquified propellant medium and indeed
the total composition is preferably such that the active ingredient does not dissolve
therein to any substantial extent. The pressurized composition may also contain a
surface active agent. The surface active agent may be a liquid or solid non-ionic
surface active agent or may be a solid anionic surface active agent. It is preferred
to use the solid anionic surface active agent in the form of a sodium salt.
[0054] A further form of topical administration is to the eye, as for the treatment of immune-mediated
conditions of the eye such as automimmue diseases, allergic or inflammatory conditions,
and corneal transplants. The compound of the invention is delivered in a pharmaceutically
acceptable ophthalmic vehicle, such that the compound is maintained in contact with
the ocular surface for a sufficient time period to allow the compound to penetrate
the corneal and internal regions of the eye, as for example the anterior chamber,
posterior chamber, vitreous body, aqueous humor, vitreous humor, cornea, iris/cilary,
lens, choroid/retina and sclera. The pharmaceutically acceptable ophthalmic vehicle
may, for example, be an ointment, vegetable oil or an encapsulating material.
[0055] Compositions for rectal or vaginal administration are preferably suppositories or
retention enemas which can be prepared by mixing the compounds of this invention with
suitable non-irritating excipients or carriers such as cocoa butter, polyethylene
glycol or a suppository wax which are solid at room temperature but liquid at body
temperature and therefore melt in the rectum or vaginal cavity and release the active
compound.
[0056] Compounds of the present invention can also be administered in the form of liposomes.
As is known in the art, liposomes are generally derived from phospholipids or other
lipid substances. Liposomes are formed by mono- or multi-lamellar hydrated liquid
crystals that are dispersed in an aqueous medium. Any non-toxic, physiologically acceptable
and metabolizable lipid capable of forming liposomes can be used. The present compositions
in liposome form can contain, in addition to a compound of the present invention,
stabilizers, preservatives, excipients, The preferred lipids are the phospholipids
and the phosphatidyl cholines (lecithins), both natural and synthetic. Methods to
form liposomes are known in the art. See, for example, Prescott, Ed.,
Methods in Cell Biology, Volume XIV, Academic Press, New York, N.Y. (1976), p. 33
et seq.
[0057] Compounds of the present invention may also be coadministered with one or more immunosuppressant
agents. The immunosuppressant agents within the scope of this invention include, but
are not limited to, IMURAN® azathioprine sodium, brequinar sodium, SPANIDIN® gusperimus
trihydrochloride (also known as deoxyspergualin), mizoribine (also known as bredinin),
CELLCEPT® mycophenolate mofetil, NEORAL® Cylosporin A (also marketed as different
formulation of Cyclosporin A under the trademark SANDIMMUNE®), PROGRAF® tacrolimus
(also known as FK-506), sirolimus and RAPAMUNE®, leflunomide (also known as HWA-486),
glucocorticoids, such as prednisolone and its derivatives, antibody therapies such
as orthoclone (OKT3) and Zenapax®, and antithymyocyte globulins, such as thymoglobulins.