Therapeutic purine agents for parkinson's disease

This application is filed under 35 USC 371 of PCT/JP94101196 filed Jul. 20, 1994 which claims parity of Japan application 184,295 filed Jul. 27, 1983.
TECHNICAL FIELD
The present invention relates to a therapeutic agent for Parkinson's disease.
BACKGROUND ART
In connection with Compounds (I) (described afterward) in the present invention, it is known that compounds represented by the following formula ##STR3## in which R.sup.1a represents hydrogen, substituted or unsubstituted lower alkyl, or lower alkanoyl, R.sup.2a represents hydrogen, lower alkenyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted aralkyl, or a substituted or unsubstituted heterocyclic group, R.sup.3a represents a substituted or unsubstituted 5-membered heterocyclic group, X.sup.a represents O, S, S(O), S(O).sub.2, or NR.sup.4a (in, which R.sup.4a represents hydrogen, or substituted or unsubstituted lower alkyl, or R.sup.2a and NR.sup.4a are combined to form a substituted or unsubstituted 4 to 6-membered saturated heterocyclic group), and A.sup.a represents N or CR.sup.5a (in which R.sup.5a represents hydrogen, or substituted or unsubstituted lower alkyl), and compounds represented by the following formula ##STR4## in which R.sup.1b represents hydrogen, substituted or unsubstituted lower alkyl, or lower alkanoyl, R.sup.2b represents substituted or unsubstituted lower alkyl, lower alkenyl, lower alkynyl, substituted or unsubstituted phenyl, or a substituted or unsubstituted 5- or 6-membered heterocyclic group, and A.sup.b represents N or CR.sup.5b (in which R.sup.5b represents hydrogen, or substituted or unsubstituted lower alkyl), have an selective adenosine A.sub.2 antagonistic activity (Japanese Published Unexamined Patent Application No. 97855.93 and EP 515107A).
Further, in connection with Compounds (II) (described afterward), it is known that compounds represented by the following formula ##STR5## in which R.sup.6a represents substituted or unsubstituted phenyl, or a substituted or unsubstituted heterocyclic group, Y.sup.a represents O, S, or NR.sup.7a (in which R.sup.7a represents hydrogen, substituted or unsubstituted lower alkyl, lower alkenyl, lower alkynyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted aryl), R.sup.8a represents hydrogen, substituted or unsubstituted lower alkyl, lower alkenyl, substituted or unsubstituted aryl, or substituted or unsubstituted aralkyl, and B.sup.a and the adjacent two carbon atoms are combined to form a substituted or unsubstituted, saturated or unsaturated, monocyclic or bicyclic, carbocyclic or heterocyclic group, have an adenosine A.sub.2 antagonistic activity and exhibits an antispasmic activity and a bronchodilating activity [Japanese Published Unexamined Patent Application Nos. 165386/86 and 135475/87, J. Med. Chem., 31, 1014 (1988)].
DISCLOSURE OF THE INVENTION
The present invention relates to a therapeutic agent for Parkinson's disease containing as an active ingredient a polycyclic compound, or a pharmaceutically acceptable salt thereof, the compound being represented by the following Formula (I): ##STR6## in which, R.sup.1 represents hydrogen substituted or unsubstituted lower alkyl, or substituted or unsubstituted lower alkanoyl; R.sup.2 represents hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted lower alkenyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl, or a substituted or unsubstituted heterocyclic group; R.sup.3 represents a substituted or unsubstituted heterocyclic group; X represents a single bond, O, S, S(O), S(O).sub.2, or NR.sup.4 (in which R.sup.4 represents hydrogen, or substituted or unsubstituted lower alkyl; or R.sup.2 and NR.sup.4 are combined to form a substituted or unsubstituted 4 to 6-membered saturated heterocyclic group); and A represents N or CR.sup.5 (in which R.sup.5 represents hydrogen, or substituted or unsubstituted lower alkyl), or represented by the following Formula (II): ##STR7## in which R.sup.6 represents substituted or unsubstituted aryl, or a substituted or unsubstituted heterocyclic group; Y represents O, S, or NR.sup.7 (in which R.sup.7 represents hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted aryl); R.sup.8 represents hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted lower alkenyl, substituted or unsubstituted lower alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl, or a substituted or unsubstituted heterocyclic group; and B and the adjacent two carbon atoms are combined to form a substituted or unsubstituted, partially saturated or unsaturated, monocyclic or bicyclic, carbocyclic or heterocyclic group.
The compounds represented by Formula (I) and Formula (II) are hereinafter referred to as Compound (I) and Compound (II), respectively, and the same applies to the compounds of other formula numbers.
In the definitions of the groups in Formula (I) and Formula (II), the lower alkyl means a straight-chain or branched alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, and hexyl. The lower alkanoyl means a straight-chain or branched alkanoyl group having 1 to 7 carbon atoms such as formyl, acetyl, propionyl, butyryl, isobutyryl, pivaloyl, and hexanoyl. The lower alkenyl means a straight-chain or branched alkenyl group having 2 to 6 carbon atoms such as vinyl, 1-methylvinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-methyl-1-propenyl, 1,3-butadienyl, 1-pentenyl, 4-pentenyl, 1-hexenyl, 1,4-hexadienyl, and 5-hexenyl. The lower alkynyl means a straight-chain or branched alkynyl group having 2 to 4 carbon atoms such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, and 2-butynyl. The cycloalkyl means a cycloalkyl group having 3 to 8 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl, a bicycloalkyl group having 7 to 12 carbon atoms such as norbornyl, or a tricycloalkyl group having 7 to 12 carbon atoms. Examples of the aryl are phenyl, naphthyl, indenyl, and anthryl. The aralkyl means an aralkyl group having 7 to 15 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl, 2-phenylpropyl, and diphenylmethyl. Examples of the heterocyclic group are furyl, thienyl, pyrrolyl, pyranyl, thiopyranyl, pyridyl, oxazolyl, thiazolyl, imidazolyl, pyrimidyl, triazinyl, indolyl, quinolyl, purinyl, benzoxazolyl, benzothiazolyl, and benzimidazolyl. Examples of the 4 to 6-membered saturated heterocyclic group are azetidino, pyrrolidino, morpholino, and thiomorpholino. Examples of the partially saturated or unsaturated, monocyclic or bicyclic carbocyclic group are cyclopentene, cyclohexene, cycloheptene, and 1,4-dihydronaphthalene. Examples of the partially saturated or unsaturated, monocyclic or bicyclic heterocyclic group are piperidein, tetrahydrobenzo[b]thiophene, isoxazole, oxazole, thiazole, pyrazole, furan, thiophene, pyrrole, pyran, thiopyran, dithine, pyrimidine, imidazole, and benzimidazole.
The substituted lower alkyl, the substituted lower alkanoyl, the substituted lower alkenyl, the substituted lower alkynyl, the substituted cycloalkyl, the substituted aryl, the substituted aralkyl, the substituted heterocyclic group, the substituted 4 to 6-membered saturated heterocyclic group, and the substituted partially saturated or unsaturated, monocyclic or bicyclic, carbocyclic or heterocyclic group each has 1 to 3 independently-selected substituents. Examples of the substituents are lower alkyl, hydroxy, hydroxy-lower alkyl, halogeno-lower alkyl, lower alkoxy, lower alkoxycarbonyl, lower alkylthio, lower alkylsulfinyl, lower alkylsulfonyl, aryloxy, aralkyloxy, halogeno-aryloxy, halogeno-aralkyloxy, carboxy, carbamoyl, lower alkanoyl, aroyl, aryl, halogen, nitro, amino, cyano, trifluoromethyl, and substituted or unsubstituted aralkyl. The lower alkyl and the lower alkyl moiety of the hydroxy lower alkyl, halogeno-lower alkyl, the lower alkoxy, the lower alkoxycarbonyl, the lower alkylthio, the lower alkylsulfinyl, and the lower alkylsulfonyl have the same meaning as the lower alkyl defined above. The aryl and the aryl moiety of the aryloxy, halogeno-aryloxy, and the aroyl have the same meaning as the aryl defined above. The aralkyl and the aralkyl moiety of the aralkyloxy and halogeno-aralkyloxy have the same meaning as the aralkyl defined above. The lower alkanoyl has the same meaning as the lower alkanoyl defined above. The halogen and the halogen moiety of the halogeno-lower alkyl, the halogeno-aryloxy, and the halogeno-aralkyloxy include fluorine, chlorine, bromine, and iodine. Examples of the substituents of the substituted aralkyl are lower alkyl, hydroxy, and halogen, and the lower alkyl and the halogen have the same meanings as the lower alkyl defined above and the halogen defined above, respectively.
The above-mentioned pharmaceutically acceptable salts of Compounds (I) and Compounds (II) include pharmaceutically acceptable acid addition salts, metal salts, ammonium salts, organic amine addition salts, and amino acid addition salts.
Examples of the pharmaceutically acceptable acid addition salts of Compounds (I) and Compounds (II) are inorganic acid addition salts such as hydrochloride, sulfate, and phosphate, and organic acid addition salts such as acetate, maleate, fumarate, tartrate, and citrate. Examples of the pharmaceutically acceptable metal salts are alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as magnesium salt and calcium salt, aluminium salt, and zinc salt. Examples of the pharmaceutically acceptable ammonium salts are ammonium salt and tetramethyl ammonium salt. Examples of the pharmaceutically acceptable organic amine addition salts are salts with morpholine and piperidine. Examples of the pharmaceutically acceptable amino acid addition salts are salts with lysine, glycine, and phenylalanine.
Compounds (I) and Compounds (II) including novel compounds can be produced according to the methods disclosed in the above-described literatures or similar methods thereto. The desired compounds in the processes can be isolated and purified by purification methods conventionally used in organic synthetic chemistry, for example, filtration, extractions, washing, drying, concentration, recrystallization, and various kinds of chromatography.
In the case where a salt of Compound (I) or Compound (II) is desired and it is produced in the form of the desired salt, it can be subjected to purification as such. In the case where Compound (I) or Compound (II) is produced in the free state and its salt is desired, Compound (I) or Compound (II) is dissolved or suspended in a suitable solvent, followed by addition of an acid or a base to form a salt.
Compounds (I), Compounds (II), and pharmaceutically acceptable salts thereof may be in the form of adducts with water or various solvents, which can also be used as the therapeutic agents of the present invention.
Some of Compounds (I) and Compounds (II) can exist in the form of optical isomers, and all possible stereoisomers including the above-mentioned ones and mixtures thereof can also be used as the therapeutic agents of the present invention. With regard to Compounds (II), isomers represented by Formula (IIb), Formula (IIc), and Formula (IId) illustrated below can exist, and all these isomers can also be used as the therapeutic agents of the present invention. ##STR8##
(In the formulae, R.sup.6, R.sup.8, Y, and B have the same meanings as defined above. )
Examples of Compound (I) and Compound (II) are shown in Table 1.
TABLE 1______________________________________ ##STR9##(Compound 1) ##STR10##(Compound 2) ##STR11##(Compound 3) ##STR12##(Compound 4)______________________________________
Compound 1: 7-Amino-2(2-furyl) -5-phenoxy [1,2,4]triazolo[1,5-a]-1,3,5-triazine (compound disclosed in Example 1 of Japanese Published Unexamined Patent Application No. 97855/93)
Melting Point: 250.7.degree.-251.7.degree. C.
Elemental Analysis: C.sub.14 H.sub.10 N.sub.6 O.sub.2
Calcd. (%): C, 57.14; H, 3.43; N, 28.56
Found (%): C, 56.89; H, 3.36; N, 28.35
NMR (DMSO-d.sub.6) .delta. (ppm): 9.00(2H, brs), 7.92 (1H, J=1.5 Hz), 7.49-7.43 (2H, m), 7.28-7.23 (3H, m), 7.12 (1H, d, J=3.0 Hz), 6.70(1H, dd, J=1.5, 3.0 Hz)
Compound 2: 7-Amino-2-(2-furyl) -5-phenoxypyrazolo [2,3-a]-1,3,5-triazine (compound disclosed in Example 119 of Japanese Published Unexamined Patent Application No. 97855/93)
Melting Point: 274.1.degree.-b 276.2.degree. C.
Elemental Analysis: C.sub.15 H.sub.11 N.sub.5 O.sub.2 .multidot. 1/4H.sub.2 O
Calcd. (%): C, 60.50; H, 3.89; N, 23.52
Found (%): C, 60.69; H, 3.54; N, 23.61
IR (KBr) .nu..sub.max (cm.sup.-1): 1664, 1603, 1552
NMR (DMSO-d.sub.6) .delta. (ppm): 8.82(1H, brs), 8.46(1H, brs ), 7.84 (1H, d, J=1.0 Hz), 7.47-7.41(2H, m), 7.28-7.21 (3H, m), 7.00(1H, d, J=3.0 Hz), 6.66(1H, dd, J=1.0, 3.0 Hz ), 6.43 (1H, s)
Compound 3: 5-Amino-9-chloro-2-(2-furyl) -1,2,4-triazolo-[1,5-c]quinazoline (compound disclosed in Example 33 of Japanese Published Unexamined Patent Application No. 165386/86)
Melting Point: 257.degree.-259.degree. C.
Elemental Analysis: C.sub.13 H.sub.8 CN.sub.5 O 0.4(CH.sub.3).sub.2 NCHO
Calcd. (%): C, 54.16; H, 3.46; N, 24.02
Found (%): C, 53.90; H, 3.31; N, 24.09
IR (KBr) .nu..sub.max (cm.sup.-1): 1682, 1614, 1589, 1555, 1528, 1480,
NMR (DMSO-d.sub.6) .delta. (ppm): 8.17(1H, d, J=2.5 Hz), 8.02(2H, brs), 7.99-7.98 (1H, m), 7.71 (1H, dd, J=2.5, 8.7 Hz), 7.57(1H, d, J=8.7 Hz), 7.28(1H, d, J=3.5 Hz), 6.76(1H, dd, J=2.5, 3.5 Hz)
.sup.13 C NMR (DMSO-d.sub.6) .delta. (ppm): 155.6, 150.8, 145.2, 144.9, 143.7, 132.2, 126.9, 126.8, 122.1, 114.1, 112.3, 112.1
Compound 4: 5-Amino-8-(4 -fluorobenzyl) -2-(2-furyl)pyrazolo-[4,3-e]-1,2,4-triazolo [1,5-c]pyrimidine [compound 18f disclosed in Eur. J. Med. Chem., 28, 569 (1993)]
Melting Point: 276.1.degree.-277.8.degree. C.
FAB-MS (M/Z): 350 (M.sup.+ +H)
IR (KBr) .nu..sub.max (cm.sup.-1): 1689, 1680, 1621, 1528, 1515, 1225
NMR (DMSO-d.sub.6) .delta. (ppm): 8.75 (1H, s), 7.94 (1H, d, J=0.7 Hz), 7.64 (2H, s), 7.43-7.38 (2H, m), 7.23-7.16 (3H, m), 6.74-6.73(1H, m), 5.49(2H, s)
The pharmacological activities of Compound (I) and Compound (II) are shown below by experimental examples.
Experimental Example 1 Effect on Locomotor Activity in Parkinson's Disease Model in Mice
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes symptoms of Parkinson's disease in humans Science, 219, 979 (1983)]. It is reported that an experimental Parkinson's disease model was obtained by administering MPTP to mice [Science, 224, 1451 (1984)]. If a compound is effective on the experimental Parkinson's disease model in mouse, the compound can be expected to have a therapeutic effect on Parkinson's disease.
The experiment was performed by using several groups of 7-weeks-old male C57BL/6 mice (weighing 20 to 24 g, Japan SLC), each group consisting of 8 mice. MPTP (RBI Co., Ltd. ) dissolved in a physiological saline solution (Otsuka Pharmaceutical Co., Ltd. ) was intraperitoneally administered to each mouse once a day for five consecutive days at a dose of 30 mg/kg. Test compounds were suspended in injectable distilled water (Otsuka Pharmaceutical Co., Ltd.) containing Tween 80 [polyoxyethylene (20) sorbitan monooleate]. L-DOPA (Kyowa Hakko Kogyo Co., Ltd. ) was suspended in 0.3% CMC (sodium carboxymethylcellulose). Thirty minutes after the final MPTP administration, the test compound suspensions and the control suspension [injectable distilled water (Otsuka Pharmaceutical Co., Ltd.) containing Tween 80] containing no test compound were orally administered to separate groups of the mice (0.1 ml per 10 g of body weight). The amount of active movements of each mouse was measured by using Automex-II (Columbus Instruments International Corp.) for the period of 30 minutes starting 30 minutes after the administration of the test compound. The effect of the compounds was evaluated by comparing the average counts of the active movements of the test compound-administered groups with those of the control groups. Statistical comparison of the values was carried out by Williams-Wilcoxon test.
The results are shown in Table 2.
TABLE 2______________________________________ Amount of Dose of Active Test Movements Compound (average countGroup Administration (mg/kg) .+-. S.E.M)______________________________________Normal MPTP (-)Control Test Compound (-) -- 1984 .+-. 122.3MPTP MPTP (+) Test Compound (-) -- 41 .+-. 14.3.sup.##Compound MPTP (+) Compound 1 (+) 10 785 .+-. 87.3**Normal MPTP (-)Control Test Compound (-) -- 1875 .+-. 77.7MPTP MPTP (+) Test Compound (-) -- 207 .+-. 85.5.sup.##L-DOPA MPTP (+) L-DOPA (+) 300 561 .+-. 271.01.sup.1)______________________________________ .sup.## p<0.01 (comparison with normal control group) **p<0.01 (comparison with MPTPtreated group) .sup.1) no significant difference as compared with MPTPtreated group)
Experimental Example 2 Effect on Haloperidol-Induced Catalepsy
The experiment was performed by using several groups of 5-weeks-old male ddY mice (weighing 22.to 24 g, Japan SLC), each group consisting of 5 mice. Haloperidol (Janssen Pharmaceutical) suspended in 0.3% CMC was intraperitoneally administered to each mouse at a dose of 1.0 mg/kg. Test compounds were suspended in 0.3% CMC or in injectable distilled water (Otsuka Pharmaceutical Co., Ltd.) containing Tween 80. L-DOPA (Kyowa Hakko Kogyo Co., Ltd.) and benserazide hydrochloride (Kyowa Hakko Kogyo Co., Ltd.) were suspended in 0.3% CMC. One hour after the haloperidol administration, the test compound suspensions and the control suspension [injectable distilled water (Otsuka Pharmaceutical Co., Ltd.) containing Tween 80] containing no test compound were orally administered to separate groups of the mice (0.1 ml per 10 g of body weight). One hour after the administration of the test compound, the forelimbs of each mouse and subsequently the hindlimbs of the same mouse were placed on a 4.5 cm-high, 1.0 cm-wide bar and catalepsy was estimated. All of the test compounds were orally administered at a dose of 10 mg/kg, and L-DOPA (100 mg/kg) and benserazide (25 mg/kg) were intraperitoneally administered together as a control experiment. The catalepsy score and the standard of judgment are shown. below.
______________________________________score duration of the cataleptic posture______________________________________0: forelimbs less than 5 seconds hindlimbs less than 5 seconds1: forelimbs from 5 (inclusive) to 10 (exclusive) seconds hindlimbs less than 5 seconds2: forelimbs 10 seconds or more hindlimbs less than 5 seconds3: forelimbs from 5 (inclusive) to 10 (exclusive) seconds hindlimbs from 5 (inclusive) to 10 (exclusive) seconds; or forelimbs less than 5 seconds hindlimbs 5 seconds or more4: forelimbs 10 seconds or more hindlimbs from 5 (inclusive) to 10 (exclusive) seconds; or forelimbs from 5 (inclusive) to 10 (exciusive) seconds hindlimbs 10 seconds or more5: forelimbs 10 seconds or more hindlimbs 10 seconds or more______________________________________
The effect of the compounds was evaluated by the total of the catalepsy scores of five mice in each group (25 points at the full). The groups wherein the total score was not more than 20 point is were estimated to be effective. The number of the animals showing remission against catalepsy is the number of the mice for which the catalepsy score was not more than 4 points. The remission rate shows the rate of decrease in total score based on that of the control group.
The ED.sub.50 (50% effective dose) values were determined using ten mice at each dose. A test compound was judged to be effective at the dose where the catalepsy score was 3 or less than 3. The ED.sub.50 values were calculated by Probit analysis.
TABLE 3______________________________________ Number of the Remission ED.sub.50Compound Total Animals Showing Rate (mg/No. Score Remission (%) kg)______________________________________0.3% Tween 80 25 0 0(Control)L-DOPA 18 4 28 107.5+ benserazide1 5 5 80 1.32 17 4 323 13 4 484 12 3 52______________________________________
Experimental Example 3 Augmentation of the Contralateral
Rotation in Rats with a 6-Hydroxydopamine-Induced
Unilateral Lesion of the Nigrostriatal Dopamine Pathway
When a unilateral lesion of the nigrostriatal pathway is induced by 6-hydroxydopamine in rodents, the sensitivity of dopamine receptors in the denervated striatum is enhanced. Administration of a dopamine against to the rodents in such a condition induces a rotational behavior to the side contralateral to the lesioned side [Acta Physiol. Scand., 367, 69 (1971)]. This model has been used for a long time as a model for the study of Parkinson's disease and in the screening of drugs for this disease [Neurol. Neurobiol.; 33, 1 (1987)].
Male Sprague-Dawley rats (weighing 200 to 240 g, Japan SLC) were pretreated with desipramine hydrochloride (25 mg/kg, i.p., Sigma Co.) 30 minutes before surgery to protect noradrenergic neurons. Then, the animals were: anesthetized with sodium pentobarbital (30 mg/kg, i.p., Dainippon Pharm. Co., Ltd.) and the nigrostriatal pathway was lesioned by injection of 6-hydroxydopamine hydrobromide (8 .mu.g, Sigma Co.) into the left medial forebrain bundle. 6-Hydroxydopamine hydrobromide was dissolved in physiological saline containing 0.05% L-ascorbic acid (Wako Pure Chem. Industries, Ltd.) to make 2 .mu.l. of solution and injected over 3 minutes.
More than 10 days after surgery, each rat was placed in a plastic bowl (30 cm in diameter). Apomorphine (0.1 mg/kg, Sandoz, AG) was injected subcutaneously arid the rats which showed a rotational behavior to the side contralateral to the lesioned side at a frequency of more than 600 counts/60 minutes after apomorphine administration were used for screening. The number of rotations was counted with an automated rotometer, in which each 180.degree. turn was counted as a rotation.
Test compounds were suspended in 0.3% sodium carboxymethylcellulose and administered orally at a dose of 10 mg/kg 30 minutes before the injection of apomorphine (0.1 mg/kg, s.c.). The counts of rotations were summed up every 5 minutes for 150 minutes after apomorphine administration. The total rotation counts induced by apomorphine (0.1 mg/kg, s.c.) with and without a test compound were statistically compared, using the same animals. Rats were allowed to rest more than 5 days between each experiment. Statistical comparison of the values was carried out by Sign-Wilcoxon test.
TABLE 4______________________________________ total rotation counts (average count .+-. S.E.M.)Compd. test compoundNo. apomorphine + apomorphine______________________________________1 706 .+-. 59 1011 .+-. 139*______________________________________ *p<0.05
Experimental Example 4 Acute Toxicity Test
Test compounds were orally administered to groups of rid-strain male mice weighing 20.+-.1 g, each group consisting of three mice. Seven days after the administration, minimum lethal dose (MLD) of each compound was determined by observing the mortality.
The MLD values of Compound 1 and Compound 2 are greater than 300 mg/kg, indicating that the toxicity of the compounds is weak. Therefore, these compounds can be safely used in a wide range of doses.
Compound (I), Compound (II), and pharmaceutically acceptable salts thereof exhibit antiparkisonism activity, and are useful as a therapeutic agent for Parkinson's disease.
Compound (I), Compound (II), and pharmaceutically acceptable salts thereof can be administered as they are, or in the form of various pharmaceutical compositions. The pharmaceutical compositions in accordance with the present invention can be prepared by uniformly mixing an effective amount of Compound (I), Compound (II), or a pharmaceutically acceptable salt thereof, as an active ingredient, with a pharmaceutically acceptable carrier. It is desired that such pharmaceutical compositions are prepared in a unit dose form suitable for oral administration or administration through injection.
For preparing a pharmaceutical composition for oral administration, any useful pharmaceutically acceptable carrier can be used. For example, liquid preparations for oral administration such as suspension and syrup can be prepared using water, sugars such as sucrose, sorbitol, and fructose, glycols such as polyethylene glycol and propylene glycol, oils such as sesame oil, olive oil, and soybean oil, preservatives such as p-hydroxybenzoates, flavors such as strawberry flavor and peppermint, and the like. Powders, pills, capsules, and tablets can be prepared using excipients such as lactose, glucose, sucrose, and mannitol, disintegrating agents such as starch and sodium alginate, lubricants such as magnesium stearate and talc, binders such as polyvinyl alcohol, hydroxypropyl cellulose, and gelatin, surfactants such as fatty acid esters, plasticizers such as glycerin, and the like. Tablets and capsules are the most useful oral unit dose forms because of the readiness of administration. For preparing tablets and capsules, solid pharmaceutical carriers are used.
Injectable preparations can be prepared using a carrier such as distilled water, a salt solution, a glucose solution, or a mixture of a salt solution and a glucose solution. The preparations can be prepared in the form of solution, suspension or dispersion according to a conventional method by using a suitable auxiliary.
Compound (I), Compound (II), and pharmaceutically acceptable salts thereof can be administered orally or parenterally as injections in the said dosage forms. The effective dose and the administration schedule vary depending upon the mode of administration, the age, body weight, and conditions of a patient, etc. However, generally, Compound (I), Compound (II), or a pharmaceutically acceptable salt thereof is administered in a daily dose of 1 to 50 mg/kg in 3 to 4 parts.
Certain embodiments of the invention are illustrated in the following examples.

BEST MODE FOR CARRYING OUT THE INVENTION
EXAMPLE 1 Tablets
Tablets having the following composition were prepared in a conventional manner.
Compound 1 (40 g) was mixed with 286.8 g of lactose and 60 g of potato starch, followed by addition of g of a 10% aqueous solution of hydroxypropylcellulose. The resultant mixture was kneaded, granulated, and then dried by a conventional method. The granules were refined to give granules used to make tablets. After mixing the granules with 1.2 g of magnesium stearate, the mixture was formed into tablets each containing 20 mg of the active ingredient by using a tablet maker (Model RT-15, Kikusui) having pestles of 8 mm diameter.
______________________________________Composition of One Tablet______________________________________Compound 1 20 mgLactose 143.4 mgPotato Starch 30 mgHydroxypropylcellulose 6 mgMagnesium Stearate 0.6 mg 200 mg______________________________________
EXAMPLE 2 Fine Granules
Fine granules having the following composition were prepared in a conventional manner.
Compound 2 (20 g) was mixed with 655 g of lactose and 285 g of corn starch, followed by addition of 400 g of a aqueous solution of hydroxypropylcellulose. The resultant mixture was kneaded, granulated, and then dried by a conventional method to give fine granules containing 20 g of the active ingredient in 1,000 g.
______________________________________Composition of One Pack of Fine Granules______________________________________Compound 2 20 mgLactose 655 mgCorn Starch 285 mgHydroxypropylcellulose 40 mg 1,000 mg______________________________________
EXAMPLE 3 Capsules
Capsules having the following composition were prepared in a conventional manner.
Compound 3 (200 g) was mixed with 995 g of Avicel and 5 g of magnesium stearate. The mixture was put in hard capsules No. 4 each having a capacity of 120 mg by using a capsule filler (Model LZ-64, Zanashi) to give capsules; each containing 20 mg of the active ingredient.
______________________________________Composition of One Capsule______________________________________Compound 3 20 mgAvicel 99.5 mgMagnesium Stearate 0.5 mg 120 mg______________________________________
EXAMPLE 4 Injections
Injections having the following composition were prepared in a conventional manner.
Compound 4 (1 g) was dissolved in 100 g of purified soybean oil, followed by addition of 12 g of purified egg yolk lecithin and 25 g of glycerine for injection. The resultant mixture was made up to 1,000 ml with distilled water for injection, thoroughly mixed, and emulsified by a conventional method. The resultant dispersion was subjected to aseptic filtration by using 0.2 .mu.m disposable membrane filters, and then aseptically put into glass vials in 2 ml portions to give injections containing 2 mg of the active ingredient per vial.
______________________________________Composition of One Injection Vial______________________________________Compound 4 2 mgPurified Soybean Oil 200 mgPurified Egg Yolk Lecithin 24 mgGlycerine for Injection 50 mgDistilled Water for Injection 1.72 ml 2.00 ml______________________________________
Industrial Applicability
According to the present invention, there can be provided an excellent therapeutic agent for Parkinson's disease.

Number	Name	Date	Kind
4831013	Francis	May 1989
5356894	Rodney et al.	Oct 1994

Number	Date	Country
181282	May 1986	EPX
217748	Apr 1987	EPX
515107	Nov 1992	EPX

Therapeutic purine agents for parkinson's disease

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