[0001] The present invention is based on the administration of drugs with binding affinity
for plasma protein and drugs regulating the effective ingredient dose of drugs with
binding affinity for plasma protein; and a pharmaceutical preparation whereby the
effective ingredient dose of drugs with binding affinity for plasma protein is regulated.
[0002] Generally, drugs administered for the purpose of medical treatment or diagnosis once
go through the systemic blood circulation, and then take the process of absorption,
distribution, metabolism, excretion and the like. In the process of absorption and
distribution, the drug moves along on flow of the blood, while it transfers to each
spaces of intravascular, interstice and intracellular by diffusion and transportation
of a free drug being in the state of unbound form with proteins, and finally the drug
arrives at the active region of target. When movement of the drug reaches a steady
state, then the free drug concentration in each space become uniform, thus the whole
pattern of the concentration of the drug is determined by the binding level with proteins.
Hence, in accordance with the property, a drug
in vivo, may partially exists in the form of reversible binding state with biopolymers such
as plasma proteins. Generally, drugs permeable through capillary wall or cell membrane
are free drugs, therefore, the transfer of such free drugs being unbound with plasma
proteins to the active region of target may be greatly influenced by the binding level
with plasma proteins.
[0003] For example, mercaptoacetylglycylglycylglycine labeled with 99m-technetium (
99mTc-MAG
3) is widely-used in renal scintigraphy, especially the renal plasma flow can be effectively
exhibited by its efficient renal extraction and renal tubular secretion. It is known
that about 90% of
99mTc-MAG
3 binds to plasma protein in an ordinary clinical dose (
Bubeck B. et al., J. Nucl. Med., 31, 1285-1295, 1990). If the binding of
99mTc-MAG
3 with plasma protein is inhibited by drugs having high binding affinity to the same
binding site on protein with
99mTc-MAG
3, then more clear renal imaging can be obtained in the earlier stage after the administration,
thus it may be thought that the dose of radioactivity to the patient can be reduced
at the same time.
[0004] On the contrary, if the binding of drugs with plasma protein is increased, then the
concentration of the free drugs in the blood can be kept in lower level for long period,
therefore, it may be possible to achieve continuous appearance of pharmacological
effects.
[0005] However, at the present stage, little is known as the research work for improving
therapeutic effect or diagnostic effect of the drugs by regulating the concentrations
of the free drugs, using the binding affinity of the second drug with plasma proteins.
[0006] Set against the above-mentioned problems, the present invention provides the use
of a second drug in the manufacture of a medicament to regulate the binding of a first
drug to a plasma protein, wherein
the first drug is a radiodiagnostic drug for in
vivo use or a radiotherapeutic drug for
in vivo use and has one group selected from bisaminothiol or its derivatives, monoaminomonoamidobisthiol
or its derivatives, bisamidobisthiol or its derivatives, mercaptoacetylglycylglycylglycine
or its derivatives, hexamethylpropyleneamineoxime or its derivatives, ethylenebis[bis(2-ethoxyethyl)phosphine]
(tetrofosmin) or its derivatives, 2,3-dimercaptosuccinic acid or its derivatives,
ethylenecysteine dimer derivatives, methoxyisobutylisonitrile derivatives, polyamine
derivatives, pyridoxylydeneaminate derivatives, methylene diphosphonate, hydroxymethylene
diphosphonate derivatives, β-methyl-ω-phenylpentadecanoic acid or its derivatives,
N-isopropyl-amphetamine, hippuric acid, benzylguanidine, and tropane derivatives,
the group being radiolabeled with one nuclide selected from 11-carbon (
11C), 15-oxygen (
15O), 18-fluorine, (
18F), 32-phosphorus (
32P), 59-iron (
59Fe), 67-copper (
67Cu), 67-gallium (
67Ga), 81m-krypton (
81mKr), 81-rubidium (
81Rb), 89-strontium (
89Sr), 90-yttrium (
90Y), 99m-technetium (
99mTc), 111-indium (
111In) , 123-iodine (
123I), 125-iodine (
125I), 131-iodine (
131I), 133-xenon (
133Xe), 117m-tin (
117mSn), 153-samarium (
153Sm), 186-rhenium (
186Re, 188-rhenium (
188Re), 201-thallium (
201T1), 212-bismuth
212Bi), 213-bismuth (
213Bi) and 211-astatine (
211At) ;
the second drug is selected from bucolome, cefazolin, etoposide, phenylbutazone, aspirin,
salicylic acid, cefatriaxone, sulfamethixzole, valproic acid, nabumetone, 6-methoxy-2-naphthyl
acetic acid, ibuprofen, probenecid, dansyl-L-asparagine (DNSA), verapamil and disopyramide;
and the first drug and the second drug have binding affinity for said plasma protein.
[0007] The second drug is administered simultaneously with the first drug or before or after
the administration of the first drug.
[0008] In a preferred embodiment, the second drug has binding affinity to the same binding
sites on the plasma protein to which the first drug has binding affinity. The medicament
comprising the second drug may be administered before, after or simultaneously with
the administration of the first drug, and such administration timing of the medicament
comprising the second drug can be suitably selected in connection with the timing
when the free drug concentration of the first drug reaches to the level so as to obtain
an adequate effect. Additionally, a single drug may be used as the second drug, or
more than one of the said second drugs may be used, in which case synergistic effect
can be expected.
[0009] Each of the first drug and the second drug may be separately filled in a container,
and may be prepared as kit form for supply. Accordingly, the present invention further
provides a product which comprises
- (a) a second drug selected from bucolome, cefazolin, etoposide, phenylbutazone, aspirin,
salicylic acid, cefatriaxone, sulfamethizole, valproic acid, nabumetone, 6-methoxy-2-naphthyl
acetic acid, ibuprofen, probenecid, dansyl-L-asparagine, verapamil and disopyramide;
- (b) a first drug which is a radiodiagnostic drug for in vivo use or a radiotherapeutic drug for in vivo use and has one group selected from bisaminothiol or its derivatives, monoaminomonoamidobisthiol
or its derivatives, bisamido-bisthiol or its derivatives, mercaptoacetylglycylglycyl-
glycine or its derivatives, hexamethylpropylene-amineoxime or its derivatives, ethylenebis[bis(2-ethoxyethyl)phosphine](tetrofosmin)
or its derivatives, 2,3-dimercaptosuccinic acid or its derivatives, ethylenecysteine
dimer derivatives, methoxyisobutylisonitrile derivatives, polyamine derivatives, pyridoxylydeneaminate
derivatives, methylene diphosphonate, hydroxymethylene diphosphonate derivatives,
β-methyl-ω-phenylpentadecanoic acid or its derivatives, N-isopropyl-amphetamine, hippuric
acid, benzylguanidine, and tropane derivatives, the group being radiolabelled with
one nuclide selected from 11-carbon (11C), 15-oxygen (15O), 18-fluorine, (18F), 32-phosphorus (32P), 59-iron (59Fe), 67-copper (67Cu), 67-gallium (67Ga), 81m-krypton (81mKr), 81-rubidium (81Rb), 89-strontium (89Sr), 90-yttrium (90Y), 99m-technetium (99mTc), 111-indium (111In), 123-iodine (123I), 125-iodine (125I), 131-iodine (131I), 133-xenon (133Xe), 117m-tin (117mSn), 153-samarium (153Sm), 186-rhenium (186Re, 188-rhenium (188Re), 201-thallium (201T1), 212-bismuth (212Bi), 213-bismuth (213Bi) and 211-astatine (211At); which first drug has binding affinity for a plasma protein for which said second
drug has binding affinity;
for simultaneous, separate or sequential use in regulating the binding affinity of
the first drug to the plasma protein.
[0010] In case of such a kit form with separate containers, they may be administered simultaneously
by mixing together when used, or each one of the first drug and the second drug can
be administered at different times separately or by different routes. The first drug
may be a commercially available pharmaceutical.
[0011] In the accompanying drawings:
Fig. 1 shows the free fraction of 99mTc-MAG3 in human plasma in the presence of site specific agent.
Fig. 2 shows the free fraction of 99mTc-MAG3 in rat plasma in the presence of site specific agent.
Fig. 3 shows the effect of bucolome on blood clearance of 99mTc-MAG3 in rat.
Fig. 4 shows the effect of bucolome on the free fraction of 99mTc-MAG, in rat blood after administration of bucolome.
Fig. 5 shows the effect of bucolome on the accumulation of 99mTc-MAG3 in rat kidney after administration of bucolome.
Fig 6 shows the effect of bucolome loading on the biodistribution of 99mTc-MAG3 in rat.
Fig. 7 shows the renogram of 99mTc-MAG3 in rat.
[0012] When the second drug as defined above is administered simultaneously with the first
drug, or before or after the administration of the first drug, then competitive displacement
will take place at the binding site, thus it can be thought that the first drug may
be released in a higher concentration (displacement effect). Therefore, it can be
expected that the higher pharmacological activity of the first drug can be obtained
as compared with the case that the first drug is administered singly. On the contrary,
when the binding fraction of the first drug to plasma protein increases by the effect
of the second drug (reducing effect of the free drug concentration), continuous appearance
of pharmacological effect of the first drug can be expected to achieve by keeping
the free fraction of the first drug in blood at a lower level for long period.
[0013] In the present invention, the first drug with binding affinity for plasma protein
may be either one of therapeutic agent or diagnostic agent, as long as it meets the
purpose of administration.
[0014] Regardless of therapeutic or diagnostic purpose, in case of obtaining the above-mentioned
displacement effect, the second drug may be preferably selected from those having
competitive binding affinity for the same plasma protein as the first drug has; increasing
the free fraction of the first drug by the binding inhibition of the first drug with
plasma protein; having the affinity for the same binding site of the first drug on
plasma protein; and having the higher binding affinity for plasma protein.
[0015] On the contrary, in case of obtaining the above-mentioned reducing effect of the
free drug concentration, the object is achieved by selecting the second drug from
those having effect to increase the binding affinity of the first drug for plasma
protein by the second drug bound to the same plasma proteins.
[0016] At the present, a report relating to research for clarifying the entity of the reducing
effect of the free drug concentration has not been found yet. While, it can be considered
that said reducing effect may appear, for example by a mechanism similar to the allosteric
effect of an enzyme, and surprisingly, it was found that the binding affinity for
the plasma protein could be increased by using the combination of the drugs shown
in Example 8 of the present invention.
[0017] Regarding dose forms of the drug, in the case that the first drug and second drug
are administered simultaneously without necessarily considering any chemical change
such as decomposition thereof by mixing together, it is possible to supply a pharmaceutical
product prepared by mixing the first drug with the second drug. In such a mixed-type
of pharmaceutical preparation, medicinally acceptable ingredients, such as pH-adjusting
agents, inorganic salts for adjusting the osmotic pressure, stabilizing agents for
stabilizing each one of these ingredients may be added thereto. The mixed-type of
pharmaceutical preparations can be processed into the suitable dose form, for example
a liquid form preparation, a lyophilized form preparation and the like, in consideration
of the constitutional ingredients, preservation stability thereof, etc. Further, the
first drug and the second drug may be separately filled in a container and prepared
in kit form for supply. Similar to the mixed-type preparation, medicinally acceptable
ingredients, such as stabilizing agents or the like may be added to each one of these
separate type of drugs, and in consideration of administeration method, stabilization
and the like, these separate type of the drugs can be processed into the suitbale
form of preparations, such as liquid form preparation, a lyophylized form preparation
and the like.
[0018] In case of the kit form mentioned above, the first drug and the second drug can be
administered separately, or can be administered simultaneously by mixing together
at the time of use. Especially, in the case of predicting changes of quality of the
product, such as decomposition of the ingredients during the storage after mixing
the first drug and the second drug, and in the case that these drugs are administered
by different route, or in the case that these drugs are administered necessarily in
different timings, the above-mentioned kit form in which the first drug and the second
drugs are filled in separate containers are useful.
[0019] Generally, as the plasma proteins bound to drug, human serum albumin (HSA), α
1-acidic glycoprotein (AGP), γ-globulin, lipoprotein and the like are exemplified,
and many drugs may bind to HSA or AGP. In selecting the second drug, for example when
the first drug has the property of mainly binding to HSA, it may be preferably selected
from an acidic drug having the binding affinity for HSA. When the first drug the property
of binding to AGP, it may be preferably selected from a basic drug having the binding
affinity for AGP. Further, in the case that the first drug has the affinity for plural
plasma proteins or has the affinity for different binding sites on the single protein,
the use of plural drugs as second drugs may be effective. Furthermore, in case of
selecting the second drug, other properties than the binding affinity with the above-mentioned
plasma protein should be considered, such as clinically acceptable appearance of the
original pharmacological activity, a broad range of usual dose, and maintenance of
high blood concentration after administration, etc.
[0020] Administration timing of the second drug may be either simultaneously with the first
drug or before or after the administration of the first drug, thus the timing is selected
suitably so as to obtain the effect to meet the administration purpose of the first
drug. Administration route of the drugs may be suitably selected from either one of
intravenous injection, intraarterial injection, subcutaneous injection, lymphaginal
injection or oral administration.
[0021] Specifically, HSA has three specific binding sites such as site I, site II and site
III on its molecule. Examples of the second drug with binding specificity at the site
I, are bucolome (5-n-butyl-1-cyclohexyl-2,4,6-trioxoperhydropyrimidine), cefazolin
(7-[1-(H)-tetrazolylacetamido]-3-[2-(5-methyl-1,3,4-thiazolyl)thiomethyl]-3-cephem-4-carboxylate),
phenylbutazone (1,2-diphenyl-3,5-dioxo-4-n-butylpyrazolidine), valproic acid (sodium
2-propylpentanoate), aspirin (2-acetoxybenzoic acid), salicylic acid (O-hydroxybenzoic
acid), ceftriaxone (disodium (6R,7R)-7-[2-amino-4-thiazoyl]-2-methoxyiminoacetamide)-3-(2,5-dihydro-2-methyl-6-oxide-5-oxo-1,2,4-triazin-3-ylthiomethyl)-8-oxo-5-thia-1-azobicyclo[4.2.0]octo-2-ene-2-carboxylate),
sulfamethizol (N-(5-methyl-1,3,4-thiadiazol-2-yl)sulfanylamide), canrenoic acid (17-hydroxy-3-oxo-17α
-pregna-4,6-dien-21-carboxylate), and dansyl-L-asparagine. Examples of the second
drug with binding specificity at the site II, are ibuprofen (2-(4-isobutylphenyl)propionic
acid), nabumetone (4-(6-methoxy-2-naphthyl)-2-butanone (6-methoxy-2-naphthylacetic
acid, which is a metabolite of nabumetone, shows binding specificity at the site II)
and probenecid (4-(N,N-dipropylsulfamoyl)benzoic acid), etc. Further, etoposide ((5S,
5aR, 8aR, 9S)-9-[(4,6,O-(R)-ethylidene-β-D-glucopyranosyl)oxy]-5,8,8a,9-tetrahydro-5-(4-hydroxy-3,5-dimethoxyphenylisobenzofuro[5,6-f][1,3]benzodioxol-6(5aH)-one)
also has binding specificity for HSA, though the binding site on the HSA has not been
assigned. As the second drug with binding specificity for AGP, the following drugs
can be exemplified, disopyramide (α-(2-diisopropylaminoethyl)-α-phenyl-2-pyridineacetamide),
verapamil (α-[3-[[2-(3,4-dimethoxyphenyl)ethyl]-methylamino]propyl]-3,4-dimethoxy-α-(1-methylethyl)benzeneacetonitrile)
and propranolol(1-isopropylamino-3-(1-naphthyloxy)-2-propanol), etc.
[0022] As compounds, such as chelating group or recetor ligand, of radio-therapeutic drug
for
in vivo use or radiodiagnostic drug for
in vivo use, both having binding affinity for plasma protein and being labeled with radioactive
nuclides, following compounds can be exemplified; mercaptoacetylglycylglycylglycine
(MAG
3) or its derivatives, hexamethylpropyleneaminoxime(HMPAO) or its derivatives, ethylenebis[bis(2-ethoxyethyl)phosphine]
(tetrofosmin) or its derivatives, 2,3-dimercaptosuccinic acid (DMSA) or its derivatives,
ethylene cysteine dimer (ECD) derivatives such as N,N'-ethylene-L-cystein diethylester
and the like, methoxyisobutylisonitrile (MIBI) derivatives, polyamine derivatives
such as diethylenetriaminepentaacetic acid (DTPA) and the like, pyridoxylideneaminate
derivatives such as pyridoxyleneisoleucine and the like; other chelating groups which
can form complex with radioactive metals such as methylene diphosphonate (MDP), hydroxymethylene
diphosphonate (HMDP) and the like; and compounds labeled with radioactive iodine such
as β-methyl-p-iodophenylpentadecanoic acid (BMIPP), N-isopropyl-p-iodoamphetamine
(IMP), iodinated hippuric acid (OIH), 3-iodobenzylguanidine (MIBG), tropane derivatives
such as N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (FP-CIT), N-methyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane
(CIT) and the like. As to the diagnostic purposes, 18-fluorine (
18F), 99m-technetium (
199mTc), 67-gallium (
67Ga), 111-indium (
111In), 123-iodine (
123I), 131-iodine (
131I) and the like are frequently used.
[0023] 99m-Technetium complex of MAG
3(
99mTc-MAG
3) is a radiopharmaceutical for
in vivo use and is widely used for the purpose of diagnosis of renopathy and uropathy, because
it possesses accumulation property to the kidney. It is known that about 90% of
99mTc-MAG
3 bind to plasma protein. For this reason,
in vitro study was conducted by using
99mTc-MAG
3 as the first drug, the serum as the plasma protein, wherein the blood cells and blood
coagulation factors are removed, and several pharmaceuticals with the binding affinity
for serum proteins as the second drug. As the result, when bucolome, valproic acid,
warfarin or the like was added, then displacement of
99mTc-MAG
3 occurred either in human serum albumin or in rat serum albumin, thus the free fraction
of
99mTc-MAG
3 in serum albumin increased. In case of bucolome, the free fraction of
99mTc-MAG
3 particularly increased (Table 1). Fig. 5 shows time course of accumulation of
99mTc-MAG
3 in the rat kidney after administering 20 mg/kg of Bucolome. Fig. 6 shows the biodistributions
in rats at 10 minutes after the administration of
99mTc-MAG
3. In this case, 10 minutes before the administration of
99mTc-MAG
3, 100 mg/kg of bucolome was administered. These results show that the amount of free
99mTc-MAG
3 was increased by bucolome loading, and rapid clearance from the blood and accumulation
of
99mTc-MAG
3 into the kidney took place.
[0024] Regarding 99m-technetium complex of diethyl ester of N,N'-ethylene-L-cystein (
99mTc-ECD), which is a radiopharmaceutical used for scintigraphy of regional cerebral
blood flow, in the
in vitro experiment by using a human serum, the displacement effect was observed by adding
Etoposide (cf. Example 4 and Table 8).
[0025] For the purpose to prove the displacement effect on organic compounds,
in vitro and
in vivo experiments were conducted by using N-isopropyl-p-iodoamphetamine (
123I-IMP) as one example of organic compounds. In
in vitro experiments, the displacement effects were observed by adding warfarin or 6-methoxy-2-naphthylacetic
acid (6-MNA), both of which have the specificity to HSA, or by adding verapamil which
has the binding specificity to AGP (cf. Example 5 and Table 9), thus the displacement
effect on organic compounds was observed and proved. Further, in the experiments by
using 6-MNA and Verapamil in which those were added separately or added simultaneously,
the synergistic effect of the displacement effect was observed, thus it is indicated
that the displacement effect can be enhanced by using plural second drugs together
(cf. Example 6 and Table 10).
[0026] In
in vivo experiments in rats, as compared with the control group (unloaded with verapamil),
the higher concentration of free
123I-IMP in blood was observed in the test group (loaded with verapamil). Reflecting
the fact, 10 minutes after the administration, the brain uptake of
123I-IMP in the test group (loaded with verapamil) was about 2 times that in the control
group (Example 7). In this
in vivo experiments, the test solution containig both of
123I-IMP and verapamil was prepared in advance (Example 7 (1)) and used it in the experiment.
Results of Example 7 indicates that it is possible to regulate the free drug concentration
by simultaneous administration of the first and second drugs using their mixture as
well as by the separate administration of the first drug and the second drugs and
the biodistribution of the first drug could reflect it.
[0027] As for an example of the reducing effect of the free drug concentration, decrease
in the free fraction (i.e., increase in binding fraction to protein) was observed
in
in vitro experiment using N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl)-nortropane
labeled with radioactive iodine (I-125) (
125I-FP-CIT) together with human serum by adding dansyl-L-asparagine (DNSA) which is
specific to the site I on albumin (cf. Example 8 and Table 15).
EXAMPLES
[0028] The present invention will be explained in more detail by illustrating the following
examples, but the invention will not be restricted only to these examples.
[0029] Methods for testing the compounds obtained and the reagents used are as follows.
- (1) Ultrafiltration: Filtration was conducted by using an equipment of ULTRACENT-10
which treats for up to 1.5 ml (manufactured by Tosoh Corp.).
- (2) 99mTcO4-: Prepared by use of a 99Mo/99mTc generator of MEDITECH (manufactured by NIHON MEDI-PHYSICS CO., LTD.) and used its
eluent as in the form of a physiological saline solution.
- (3) Reagents: The all reagents used were "Extra-pure reagent grade".
- (4) Test animals: The all test animals used were Wister-strain male rats (body weight:
200-250g). Prior to the test, the animals were breeded under light-dark cyclic condition
in every 12 hours for 1 week, and had free access to food and water.
Example 1
Examination of displacement effects of the second drugs on 99mTC-MAG3 binding to plasma protein
[0030] Displacement test of
99mTc-MAG
3 binding to serum albumin was conducted as follows by use of human serum or rat serum
and site-specific drugs (second drugs) with binding affinity for the binding site
I or site II on albumin. Bucolome, valproic acid, warfarin and cefazolin were used
as site-specific drugs with binding affinity for the site I, and ibuprofen, sodium
octanoate and sodium oleate were used as site-specific drugs with binding affinity
for the site II.
[0031] First, albumin content in a normal human serum was measured previously, and the concentration
of the human serum albumin (HSA) was adjusted to 500 µM by phosphate buffer (pH=7.4).
[0032] Further, a site-specific drug with the binding affinity for the site I or the site
II on HSA was added to the above-mentioned serum solution, as in the form of a methanol
solution or an aqueous solution. As the sample solution for control group, only methanol
or water was added to the above-mentioned serum solution.
[0033] Next, a certain amount of
99mTc-MAG
3 (about 740 kBq/20 µl) was added to each of the sample and a certain amount (20-50
µl) of the sample was taken out as the specimen before ultrafiltration. Each 0.9 mL
of the samples was put in a ultrafilter and conducted ultrafiltration under the condition
of 1500 X g, for 10 minutes. Then, 20-50 µl each of the filtrates was taken out as
the specimen after ultrafiltration. Radioactivities (cpm) of the specimens before
and after ultrafiltration were measured, and the free fraction (%) of
99mTc-MAG
3 was calculated by the following equation:
- [A]: Radioactivity (cpm) after ultrafiltration,
- [B]: Radioactivity (cpm) before ultrafiltration
[0034] Similarly, albumin content in normal rat serum was previously measured, and the concentration
of the rat serum albumin (RSA) was adjusted to 375
µM by phosphate buffer (pH=7.4) so as to conduct the test similar to that of the case
of human serum. The results are shown in Table 1, Fig.1 and Fig.2.
[0035] In the case of human serum, the free fraction (%) of
99mTc-MAG
3 in the test samples to which a site-specific drug to site I was added, such as bucolome,
valproic acid, warfarin or cefazolin, was significantly increased as compared with
the free fraction (10.2%) of
99mTc-MAG
3 of the control sample.
[0036] On the other hand, in other test samples to which a site-specific drug to site II
was added, such as ibuprofen, sodium octoate or sodium oleate, increase in the free
fraction was not observed.
[0037] Similarly, in test samples of the rat serum to which a site-specific drug to site
I was added, increase in the free fraction (%) of
99mTc-MAG
3 was observed.
[0038] As can be seen from the above results, it is clearly indicated that the free fraction
of
99mTc-MAG
3 in the blood can be increased by adding a site-specific drug to site I. Although,
warfarin, octanoic acid and oleic acid might be considered clinically unsuitable for
the purpose of this invention, they were used for the confirmation of the effects
of site-specific drugs to the binding site.
Table 1. Displacement effects of the second drugs on
99mTc-MAG
3 binding to plasma protein
| Site-specific drug (second drug) |
Human serum albumin (HAS) 99mTc-MAG3 free fraction (%) |
Rat serum albumin (RSA) 99mTc-MAG3 free fraction (%) |
| concentration |
200 µM |
400 µM |
200 µM |
400 µM |
| Control |
10.20% |
24.75% |
| bucolome |
12.23% |
13.74% |
32.76% |
43.85% |
| valproic acid |
11.98% |
13.02% |
28.48% |
29.30% |
| warfarin |
11.50% |
13.57% |
33.57% |
43.28% |
| cefazolin |
11.13% |
14.76% |
28.58% |
33.52% |
| ibuprofen |
10.18% |
10.53% |
28.48% |
33.04% |
| octanoic acid |
9.60% |
9.86% |
- |
- |
| oleic acid |
8.74% |
9.44% % |
- |
- |
Example 2
Biodistribution of 99mTc-MAG3 in rat loaded with bucolome
[0039] Effect of second drug on biodistribution of
99mTc-MAG
3 in rat was examined using the control group and the test group with bucolome loading.
99mTc-MAG
3 (740 kBq/100
µl) was administered to the tail vein of Wister-strain rat. The rats were decapitated
at 2, 5, 10 and 15 minutes after administration of
99mTc-MAG
3, then the blood and the organs of interest were excised. After measured the weight
of these orgams, the radioactivities were determined. After decay correction of the
radioactivity, the accumulation ratios (% dose/organ and % dose/g of the tissue) were
determined.
[0040] As for the rat of test group loaded with bucolome, 5 minutes before the administration
of
99mTc-MAG
3, 20 mg/kg of body weight or 100 mg/kg of body weight of bucolome was administered
to the tail vein.
[0041] The results are shown in Table 2 and Table 3 (control group), Table 4 and Table 5
(test group, loaded with 20 mg/kg of bucolome) and Table 6 (test group, loaded with
100 mg/kg of bucolome).
[0042] In the control group and test group with bucolome loading of 20 mg/kg of body weight,
wherein the dose and other conditions were the same as mentioned above, except the
decapitation time was prescribed at 2, 5 and 10 minutes, administrations and decapitations
of rats were conducted so that 3-5 ml of blood per one rat were collected. Serum was
separated using a sample tube, after that the free fraction was determined by the
procedures as described in Example 1. The time course of the free fraction of
99mTc-MAG
3 in vivo are shown in Fig. 4.
[0043] From the results shown above, it has become appearant that blood clearance was accelarated
in the test group with bucolome loading (Fig. 3), and the free fraction of
99mTc-MAG
3 in vivo in test group was remarkably increased (Fig. 4).
[0044] In the control group, accumulation of
99mTc-MAG
3 in the kidney (% dose/organ) increased from 2 minutes to 5 minutes after the administration,
then gradually decreased and disappeared. While, in test group with bucolome loading,
accumulation of
99mTc-MAG
3 in the kidney rapidly increased to the maximum value just after the administration
(in 2 minutes), then decreased and disappeared quickly as compared with that of the
control group (Fig. 5).
[0045] Biodistribution of
99mTc-MAG
3 (% dose/g tissue) in rat 10 minutes after the administration is shown in Fig. 6.
As can be seen from Fig. 6, in the test group with bucolome loading,
99mTc-MAG
3 was rapidly cleared from the kidney which is the target organ of
99mTc-MAG
3, thus radioactivity was quickly cleared as compared with that of the control group.
Clearance from the blood and other organs were also rapid.
Table 2. Biodistribution of
99mTc-MAG
3 in rats (Control group: % dose/organ)
| Organs |
2 minutes |
5 minutes |
10 minutes |
15 minutes |
| Spleen |
0.110 ± 0.024 |
0.064±0.001 |
0.025±0.006 |
0.01,9±0.001 |
| Pancreas |
0.137±0.026 |
0.079±0.013 |
0.084±0.050 |
0.030±0.001 |
| Stomach |
0.276±0.011 |
0.169±0.003 |
0.119±0.043 |
0.178±0.009 |
| Liver |
5.196±0.387 |
5.187±2.759 |
1.671±0.099 |
0.973±0.266 |
| Kidney |
23.882±4.669 |
31.329±4.979 |
29.198±3.729 |
15.864±3.960 |
| Heart |
0.262±0.039 |
0,184±0.046 |
0.079±0.028 |
0.034±0.004 |
| Lung |
0.635±0.116 |
0.594±0.106 |
0.275±0.042 |
0.129±0.084 |
| Urine |
0.236±0.119 |
1.309±0.941 |
16.872±4.042 |
38.419±2.150 |
Table 3. Biodistribution of
99mTc-MAG
3 in rats (Control group: % dose/g tissue)
| Organs |
2 minutes |
5 minutes |
10 minutes |
15 minutes |
| Blood |
1.482±0.137 |
0.968±0.163 |
0.387±0.018 |
0.160±0.022 |
| Spleen |
0.171±0.031 |
0.104±0.014 |
0.094±0.008 |
0.026±0.006 |
| Pancreas |
0.233±0.029 |
0.150±0.001 |
0.096±0.027 |
0.098±0.007 |
| Stomach |
0.176±0.011 |
0.031±0.012 |
0.015±0.010 |
0.110±0.050 |
| Liver |
0.579±0.081 |
0.523±0.268 |
0.145±0.009 |
0.100±0.024 |
| Kidney |
13.039±3.199 |
16.721±0.992 |
15.526±2.763 |
8.282±1.222 |
| Heart |
0.448±0.056 |
0.290±0.099 |
0.128±0.031 |
0.057±0.010 |
| Lung |
0.621±0.100 |
0.970±0.069 |
0.213±0.008 |
0.112±0.057 |
Table 4. Biodistribution of
99mTc-MAG
3 in rats (Test group with 20 mg/kg bucolome loading: % dose/organ)
| Organs |
2 minutes |
5 minutes |
10 minutes |
15 minutes |
| Spleen |
0.103±0.001 |
0.048±0.006 |
0.018±0.009 |
0.011±0.003 |
| Pancreas |
0.239±0.072 |
0.139±0.030 |
0.060±0.023 |
0.075±0.053 |
| Stomach |
0.289±0.057 |
0.153±0.023 |
0.111±0.032 |
0.104±0.040 |
| Liver |
7.289±0.333 |
3.140±0.745 |
1.217±0.471 |
0.806±0.187 |
| Kidney |
26.404±2.243 |
22.952±9.437 |
17.118±8.295 |
9.544±3.655 |
| Heart |
0.210±0.034 |
0.114±0.019 |
0.037±0.012 |
0.029±0.014 |
| Lung |
0.792±0.044 |
0.456±0.137 |
0.148±0.079 |
0.085±0.025 |
| Urine |
0.802±0.709 |
2.692±2.721 |
14.792±9.307 |
23.969±18.025 |
Table 5. Biodistribution of
99mTc-MAG
3 in rats (Test group with 20 mg/kg bucolome loading: % dose/g tissue)
| Organs |
2 minutes |
5 minutes |
10 minutes |
15 minutes |
| Blood |
1.050±0.057 |
0.544±0.043 |
0.186±0.076 |
0.152±0.088 |
| Spleen |
0.153±0.018 |
0.083±0.005 |
0.026±0.011 |
0.018±0.006 |
| Pancreas |
0.314±0.013 |
0.145±0.017 |
0.062±0.021 |
0.088±0.052 |
| Stomach |
0.145±0.121 |
0.033±0.017 |
0.033±0.020 |
0.032±0.012 |
| Liver |
0.853±0.135 |
0.280±0.017 |
0.117±0.035 |
0.088±0.028 |
| Kidney |
13.069±0.379 |
11.050±4.260 |
8.558±3.867 |
9.809±1.823 |
| Heart |
0.329±0.034 |
0.172±0.021 |
0.057±0.017 |
0.095±0.021 |
| Lung |
0.613±0.013 |
0.373±0.073 |
0.120.±0.099 |
0.081±0.020 |
Table 6. Biodistribution of
99mTc-MAG
3 in rats 10 minutes after the administration (Test group with 100 mg/kg bucolome loading:
% dose/g tissue)
| Organs |
Control group |
Test group with bucolome loading |
| Blood |
0.317±0.073 |
0.047±0.044 |
| Brain |
0.010±0.001 |
0.001±0.001 |
| Spleen |
0.052±0.008 |
0.009±0.008 |
| Pancreas |
0.046±0.000 |
0.006±0.007 |
| Stomach |
0.024±0.024 |
0.040±0.036 |
| Liver |
0.151±0.001 |
0.033±0.026 |
| Kidney |
6.191±0.187 |
0.651±0.324 |
| Heart |
0.101±0.016 |
0.014±0.010 |
| Lung |
0.195±0.030 |
0.043±0.037 |
Example 3
Examination of displacement effect on 99mTc-MAG3 by means of renography in rats
[0046] By using Wistar-strain rats (body weight: 400g), displacement effect of bucolome
on
99mTc-MAG
3 was examined by means of renography in rats. Prism 3000 (picker) was used as an apparatus.
[0047] A catheter was inserted into the femoral vein of the rat, then
99mTc-MAG
3 (11.1 MBq) was injected through the catheter and the control renogram was obtained.
The dynamic imaging was conducted 10 seconds/scan for 20 minutes. About 2 hours after,
confirming the urination and decrease in background radioactivity, then bucolome was
loaded to the same rat. Bucolome was dissolved in ethanol and adjusted as in the dose
of 20 mg/kg, then intravenously injected by using a microinjector taken in 10 minutes.
About 5 minutes after finish of the intravenous injection of bucolome,
99mTc-MAG
3 was intravenously injected through the catheter and the renogram was taken similarly
by 10 seconds/scan for 20 minutes. Fig. 7 shows the renogram (time-radioactivity curves
in the kidney) used for functional analysis of the kidney. As can be seen from the
Fig. 7, in the control group, the radioactivity curve went up gradually at the initial
stage after the administration, and the peak time was 240 seconds. On the other hand,
in the test group with bucolome loading, the radioactivity curve rose quickly, and
the peak time was 120 seconds which was a half length of that of the control group.
Renal function is usually analyzed by determination of the peak time in this renogram
and a slope of the straight line in a linear regression. By inhibiting the binding
ability of
99mTc-MAG
3 to plasma protein, the renogram was obtained as close to an ideal and was apploximated
to a simple curve. Thus, the functional analysis of the kidney can be easily carried
out, and the time for functional analysis can be shortened by shortening the peak
time.
Table 7. Analytical results of renogram of
99mTc-MAG
3 in rats
| |
Peak time (Second) |
Slope (Count/second) |
| Rat 1 |
| |
Control group |
240 |
1.166 |
| |
Test group (with bucolome loading) |
110 |
2.208 |
| Rat 2 |
| |
Control group |
170 |
0.941 |
| |
Test group (with bucolome loading) |
120 |
2.000 |
Example 4
Examination of displacement effects of the second drugs on 99mTc-EDC binding to plasma protein
[0048] Displacement experiment of
99mTc-ECD binding to a serum albumin was conducted by procedures similar to those shown
in Example 1 using human serum; and bucolome, valproic acid, warfarin and cefazolin
with binding specificity to the site I on albumin; ibuprofen and sodium octanoate
with binding specificity to the site II on alubumin; and etoposide with binding specificity
to HAS on which binding site is not identified. The results are shown in Table 8.
[0049] As compared with the free fraction (26.03%) of
99mTc-ECD in human serum shown in control group, the free fraction of
99mTc-ECD in human serum were remarkably increased in test group by etoposide, both at
the concentration of 200 µM and 400 µM. Similarly, the free fraction of
99mTc-ECD in human serum were also incresed by bucolome, valproic acid and warfarin,
but were not remarkably shown as compared with that of etoposide. On the contrary,
the free fraction of
99mTc-ECD in human serum were not clearly increased by ibuprofen and sodium octanoate
which have the specificity to the site II on albumine.
Table 8 Displacement of
99mTc-ECD binding to plasma protein
| Site-specific drug (second drug) |
free fraction of 99mTc-ECD (%) |
| Concentration |
200 µM |
400 µM |
| Control |
26.03% |
| Bucolome |
28.62% |
30.25% |
| Valproic acid |
28.36% |
30.25% |
| Warfarin |
31.00% |
31.37% |
| Cefazolin |
25.92% |
27.40% |
| Etoposide |
33.26% |
37.38% |
| Ibuprofen |
23.09% |
24.09% |
| Octanoic acid |
28.22% |
29.64% |
Example 5
Examination of displacement effects of the second drugs on 123I-IMP binding to plasma protein
[0050] Displacement experiment of
123I-IMP binding to a serum albumin was conducted by procedures similar to those shown
in Example 1 using human serum; and as the second drug, bucolome and warfarin with
binding specificity to the binding site I on albumin; ibuprofen, sodium octanoate,
6-methoxy-2-naphthylacetic acid (6-MNA) with binding specificity to the binding site
II on alubumin; and verapamil which has the specificity to α
1-acid glycoprotein (AGP). Concentration of the second drug (e.g., bucolome) was 400
µM and added amount of
123I-IMP was about 220 kBq/20 µL. The results are shown in Table 9.
[0051] As compared with free fraction (29.29%) of
123I-IMP in human serum shown in control group, the free fraction of
123I-IMP in human serum in test group was remarkably incresed by adding verapamil with
binding specificity to AGP. Further, the free fraction of
123I-IMP binding in human serum in test group was also increased by warfarin and 6-MNA
mainly bound to albumin. In view of these facts, it is suggested that
123I-IMP binds to the binding site on both albumin and AGP, and it is clearly understood
that the free fraction of
123I-IMP can be increased by a drug having the specificity to each binding sites of these
proteins.
Table 9. Displacement of
123I-IMP binding to human plasma protein (Concentration of the site-specific drug was
400 µM)
| Site-specific drug (second drug) |
free of fraction of 123I-IMP (%) |
| Control |
29.29% |
| bucolome |
30.26% |
| warfarin |
34.69% |
| ibuprofen |
28.43% |
| octanoic acid |
28.74% |
| 6-MNA |
32.70% |
| verapamil |
38.34% |
Example 6
Examination of displacement effects of the second drugs on 123I-IMP binding to plasma protein; synergistic effect
[0052] Displacement experiment of
123I-IMP binding to serum albumin was conducted by procedures similar to those shown
in Example 5 using human serum and as the second drugs, 6-MNA having the specificity
to the binding site II on albumin and verapamil having the specificity to the binding
site on AGP. Concentration of the second drugs were 400 µM and the added amount of
123I-IMP was about 220 kBq/20 µL.
[0053] The tests were conducted in one group by using 6-MNA or verapamil independently,
and in another group by using 6-MNA and verapamil simultaneously to study synergistic
effect. In both groups, concentrations of the second drugs were 400 µM. The results
are shown in Table 10.
[0054] In case of using 6-MNA and verapamil simultaneously, the free fraction of
123I-IMP was over than the sum of the corresponding values obtained by single use of
6-MNA or verapamil, respectively. In view of the above facts, synergistic effect can
be expected by using the plural second drugs.
Table 10. Displacement of
123I-IMP binding to human plasma protein: synergistic effect
| Site-specific drug (second drug) |
free fraction of 123I-IMP |
| Control |
26.52% |
| 6-MNA |
30.00% |
| verapamil |
33.87% |
| 6-MNA + verapamil |
39.26% |
Example 7
Biodistribution of 123I-IMP in rat with verapamil loading (1) Preparation of 123I-IMP·verapamil mixed solution
[0055] 35 Milligrams of verapamil bulk drug powder was dissolved in 2 ml of Vasolan injection
(verapamil 5 mg/2 ml, manufactured by Eisai Co., Ltd.), then 34
µL of
123I-IMP injection (111 MBq/ml, manufactured by NIHON MEDI-PHYSICS CO., LTD.) was added
thereto and mixed throughly.
(2) Biodistribution of 123I-IMP in rats
[0056] Control group:
123I-IMP Injection solution (185 kBq/300 µL) being diluted with physiological saline
was administered via the caudal vein of rats of control group. The rats were decapitated
at 2, 5, 10, 30 and 60 minutes after administration. Then the blood was sampled and
the organs of interest were excised. After measured the weight of these specimens,
the radioactivities of the blood and organs were measured. After half-life of the
radioactivities were corrected, the accumulation rate (% dose/g of the tissue) was
obtained.
[0057] Test group: 100
µL of
123I -IMP·verapamil mixed solution was administered via the caudal vein of rats of the
test group (about 10 mg/kg loaded as verapamil), then the rats were treated similarly
to those of control group. The results of biodistribution of
123I-IMP are shown in Table 11 (control group), Table 12 (test group with verapamil loading),
and Table 13 (comparison of both control and test groups of 10 minutes after the administration).
(3) Examination of displacement effect on 123I-IMP binding to plasma protein in rat
[0058] Under the same conditions as mentioned above concerning the constitution of control
and testing group, timings of decapitation, and dose of drugs, administrations of
the drugs and decapitations of rats were conducted, and 3-5 ml of blood per one rat
was sampled. Serum was separated using a sample tube, after that the free fraction
of
123I-IMP was determined by the procedures as described in Example 1. The free fraction
of
123I-IMP in the blood sample of rat obtained at each decapitation timing are shown in
Table 14.
[0059] As shown in Table 14, it is clearly indicated that the free fraction of
123I-IMP in the blood sample of rat were increased by the loading with the verapamil.
As shown in Table 11 through Table 13, corresponding to increasing in the free fraction
of
123I-IMP in the blood due to the loading with verapamil, the uptake of
123I-IMP into the brain which is the target organ of
123I-IMP was rapidly increased after administration of
123I-IMP·verapamil mixed solution in the test group, thus the brain uptake of
123I-IMP in the test group after the administration was increased about 2 times higher
than that of shown in control group. These facts indicate that, even if a mixed drug
of the first drug and the second drug is administered (simultaneous administration
of the first drug and the second drug), the free fraction of
123I-IMP can be regulated by the second drug, and the biodistribution of the first drug
could reflect it.
Table 11. Biodistribution of
123I-IMP in rats (Control group: % Dose/g Tissue)
| Tissues |
2 Minutes |
5 Minutes |
10 Minutes |
30 Minutes |
60 Minutes |
| Blood |
0.198±0.052 |
0.133±0.005 |
0.116±0.011 |
0.136±0.028 |
0.181±0.006 |
| Brain |
1.800±0.418 |
1.476±0.225 |
1.006±0.379 |
1.396±0.395 |
1.511±0.011 |
| Pancreas |
1.503±0.353 |
1.923±0.445 |
1.721±0.217 |
2.032±0.505 |
1.957±0.345 |
| Spleen |
0.880±0.216 |
0.999±0.355 |
1.008±0.074 |
1.356±0.277 |
1.290±0.138 |
| Stomach |
0.302±0.065 |
0.500±0.078 |
0.407±0.230 |
0.885±0.366 |
1.295±0.393 |
| Liver |
0.506±0.109 |
0.699±0.061 |
0.711±0.143 |
1.192±0.536 |
1.442±0.164 |
| Kidney |
3.406±0.905 |
2.285±0.256 |
1.303±0.190 |
1.359±0.222 |
1.585±0.132 |
| Heart |
1.949±0.293 |
1.014±0.070 |
0.631±0.111 |
0.529±0.037 |
0.540±0.026 |
| Lung |
11.236±0.780 |
9.000±0.600 |
6.279±1.026 |
5.209±1.446 |
5.186±0.616 |
Table 12. Biodistribution of
123I-IMP in rats (Test group (Loaded with verapamil): % Dose/g Tissue)
| Tissues |
2 Minutes |
5 Minutes |
10 Minutes |
30 Minutes |
60 Minutes |
| Blood |
0.238±0.083 |
0.228±0.012 |
0.139±0.003 |
0.098±0.044 |
0.110±0.002 |
| Brain |
1.584±0. 425 |
1.916±0.131 |
2.145±0.410 |
1.529±0.811 |
1.449±0.281 |
| Pancreas |
1.268±0.375 |
1.659±0.496 |
1.911±0.685 |
1.877±0.886 |
1.478±0.161 |
| Spleen |
0.052±0.025 |
0.063±0.250 |
0.213±0.118 |
0.886±0.319 |
1.193±0.129 |
| Stomach |
0.234±0.111 |
0.164 ±0.078 |
0.377±0.013 |
0,782±0.621 |
1.058±0.126 |
| Liver |
0.287±0.156 |
0.350±0.130 |
0.688±0.237 |
1.185±0.751 |
1.639±0.051 |
| Kidney |
1.424±0.313 |
1.278±0.381 |
1.766±0.678 |
1.231±0.632 |
1.242±0.146 |
| Heart |
3.769±0.911 |
2.260±0.680 |
1.247±0.209 |
0.471±0.209 |
0.456±0.039 |
| Lung |
9.234±1.748 |
8.377±0.563 |
6.947±1.486 |
3.890±2.223 |
9.133±0.079 |
Table 13. Biodistribution of
123I-IMP in rats 10 minutes after the administration (% Dose/g Tissue)
| Tissue |
Control group |
Test group with verapamil loading |
| Blood |
0.116±0.011 |
0.139±0.003 |
| Brain |
1.006±0.379 |
2.145±0.410 |
| Pancreas |
1.721±0.217 |
1.911±0.685 |
| Spleen |
1.008±0.074 |
0.213±0.118 |
| Stomach |
0.407±0.230 |
0.377±0.013 |
| Liver |
0.711±0.143 |
0.688±0.237 |
| Kidney |
1.303±0.190 |
1.766±0.678 |
| Heart |
0.631±0.111 |
1.247±0.209 |
| Lung |
6.279±1.026 |
6.947±1.486 |
Table 14. Free fraction (%) of
123I-IMP in the blood of rats
| |
2 Minutes |
5 Minutes |
10 Minutes |
30 Minutes |
60 Minutes |
| Control group |
56.75±9.21 |
50.70±10.37 |
45.91±3.12 |
27.29±4.85 |
16.77±4.11 |
| Test group with verapamil loading |
52.40±6.00 |
56.52±4.38 |
66.86±6.34 |
38.03±6.69 |
31.86±8.23 |
Example 8
Examination of regulating the free fraction of 125I-FP-CIT
[0060] Experiment was conducted by procedures similar to those shown in Example 5 using
human serum and as the second drug, bucolome, phenylbutazone, warfarin and dansyl-L-asparagine
(DNSA) with binding specificity to the binding site I on albumin, and ibuprofen, 6-methoxy-2-naphthylacetic
acid (6-MNA) with binding specificity to the binding site II on albumin. Concentration
of the second drug (e.g., bucolome and the like) were 400 µM and added amount of
123I-FP-CIT was about 74 kBq/20 µL. The result are shown in Table 15.
[0061] As compared with the free fraction (17.26%) of
123I-FP-CIT in human serum shown in control group, the free fraction of
123I-FP-CIT in test group was remarkably decresed by DNSA. Furthermore, the free fraction
of
123I-FP-CIT in test group was also decreased by phenylbutazone and ibuprofen. In view
of these facts, it is clearly understood that the free fraction of the first drug
can be decreased by the second drug having the binding affinity for the plasma proteins.
Table 15. Free fraction of
123I-FP-CIT in human serum (concentration of the site-specific drug was 400
µM)
| Site-specific drug (second drug) |
free fraction (%) of 123I-FP-CIT |
| Control |
17.26% |
| bucolome |
18.40% |
| phenylbutazone |
14.92% |
| warfarin |
17.88% |
| DNSA |
12.80% |
| ibuprofe |
15.92% |
| 6-MNA |
18.10% |