Use of piperazine compounds as narcotic antagonists

Abstract: A narcotic antagonist comprising, as its active component, a compound represented by the following formula (1) or a physiologically acceptable salt thereof: wherein each of R 1 and R 2 , which may be identical to or different from each other, represents a hydrogen atom or a halogen atom; R 3 represents a hydrogen atom, an alkyl group, or an acyl group; R 4 represents a hydrogen atom, an alkyl group, an acyl group, an alkylsulfonyl group, or a carboxyl group which may be esterified; Ar represents a phenyl group which may have 1 to 3 substituents selected from the group consisting of a halogen atom, an alkyl group, an alkoxyl group, a nitro group, an amino group, an alkylamino group, and a hydroxyl group or Ar represents a monocyclic aromatic heterocyclic ring having a nitrogen atom; m represents a number of 1 to 5 inclusive; and n represents a number of 0 to 5 inclusive. Also, a medicament for the prevention and treatment of narcotic dependence is provided.

Description: Field of the Invention : The present invention relates to narcotic antagonists and medicaments for the prevention and treatment of narcotic dependence. Background Art : Narcotics, typically represented by cocaine, have rapidly spread worldwide since the Vietnam War. Because narcotics cause strong dependency, once a user becomes dependent on them, it is difficult for the user to abandon his habitual use of them. Thus, despite great efforts made in many countries for controlling narcotics, any attempts so far have been unsuccessful, and permitted them to further spread worldwide. Under the above circumstances, various attempts have been made to develop compounds for treating cocaine dependence. For example, certain piperazine derivatives which act on neuroreceptors have been found to have a therapeutic action for narcotic dependence (International Patent Publication ( kohyo ) No. 4-504859). However, when such a piperazine derivative is used at a concentration high enough to cure narcotic dependence, it often happens that the derivative also strongly exhibits other activities, giving adverse side effects. Therefore, substances that strongly act on narcotic receptors are still desired. International patent application WO 95/00149 describes dopamine (DA) reincorporation inhibitors containing compounds represented by general formula (1) or a physiologically acceptable salt thereof as the active ingredient wherein R 1 and R 2 represent each hydrogen or halogen; R 3 represnts hydrogen, alkyl or acyl; R 4 represents hydrogen, alkyl, acyl, alkylsulfonyl or optionally esterified carboxyl; Ar represents optionally substituted phenyl or a nitrogenous monocyclic heretoaromatic group; m represents a number of 1 to 5; and n represents a number of 0 to 5. These inhibitors do not produce any side effect, are safe, have potent activities of inhibiting DA reincorporation and enhancing autonomic movement, and are very useful for treating Parkinson's syndrome believed to be a disease caused by DA deficiency. International patent application WO 92/16211 describes the use of certain diphenylbutyl-piperazinecarboxamides, especially amperozide, 4-[4,4-bis(4-fluorophenyl)butyl]-N-ethyl-1-piperazinecarboxamide, and salts thereof, in the treatment of substance abuse disorders. More particularly, this treatment relates to the amelioration of withdrawal symptoms and to modifying drug-seeking behaviour. This document also mentions the beneficial effect of compounds which are active as serotonin or dopamine uptake inhibitors in the prevention or treatment of dependence of drugs such as nicotine and, analogs. British patent 1 497 083 describes 1-substituted-4-(1,2-diphenylethyl)-piperazine derivatives of the following formula: wherein X is hydroxy, methoxy, methyl or trifluoromethyl; and R is an unsubstituted monocycloalkyl group having 6 to 8 carbon atoms or 2-methoxyphenyl, provided that, when X is hydroxy, R is cyclohexyl, and when X is trifluoromethyl, R is 2-methoxyphenyl, and their pharmaceutically acceptable acid addition salts, having analgesic, anti-tussive and anti-flammatory pharmacological activities. In view of the foregoing, the present inventors carried out extensive screenings using narcotic antagonism as an index and found that the compounds described below possess strong narcotic antagonism and thus are useful as preventive and therapeutic agents for narcotic dependence. The present invention was accomplished based on this finding. SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to provide use of a compound selected from the group consisting of 1-[4, 4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[bis(4-fluorophenyl)methyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HC1, 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-benzylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-methoxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-[3-(4-fluorophenylamino)-2-hydroxypropyl]piperazine · 2HC1, (-)-1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, (+)-1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-(4-pyridylamino)propyl]piperazine · 2C 4 H 4 O 4 , 1-[3,3-bis(4-fluorophenyl)propyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, and 1-[5,5-bis(4-fluorophenyl)pentyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl for the manufacture of narcotic antagonists or medicaments for the prevention and treatment of narcotic dependence. DESCRIPTION OF PREFERRED EMBODIMENTS The compounds referred to above are known per se . They are also known to have calcium antagonism, dopamine reuptake inhibiting action, serotonin reuptake inhibiting action, and anti-oxidization action (WO92/05165). However, their strong narcotic antagonism was never known until reported by the present invention. The compounds of the present invention may be prepared, for example, by the method described in WO92/05165. They are usually colorless to pale yellow liquids, amorphous, or solids. They are slightly soluble in water and are soluble in organic solvents such as methanol, chloroform, or benzene. Compounds of claim 1 can be readily purified by routine methods such as column chromatography or recrystallization. Compounds of claim 1 may be converted into salts when they are mixed with acids. Acids usable for this purpose are not particularly limited so long as the resultant salts are physiologically acceptable. Examples of usable acids include mineral acids such as hydrochloric acid, phosphoric acid, sulfuric acid; and organic acids such as citric acid, oxalic acid, acetic acid, fumaric acid, maleic acid, maronic acid, and methanesulfonic acid. Of the listed acids, maleic acid is particularly preferred from the viewpoints of easy handling, low cost, and good chemical properties. The thus-formed salts are generally white, pale yellow, or pale blue solids. The compounds of claim 1 are shown in Tables 1 through 5 below, together with a number of comparison compounds which are identified as such with an asterisk. In the process of antagonizing narcotics, compounds of claim 1 strongly bind to narcotic receptors so as to inhibit narcotics from binding to narcotic receptors. Needless to say, compounds of claim 1 do not have any narcotic-like action. Therefore, they are useful as narcotic antagonists and medicaments for the prevention and treatment of narcotic dependence. Narcotics to which the medicines of the present invention are particularly effective include cocaine, amphetamine, and phencyclidine. It is expected that the compounds are most effective on cocaine. They exhibit very strong effects on cocaine as shown in the Examples described below. Toxicities of the compounds of claim 1 are very low, as described in WO92/05165, each having a LD 50 value of not less than 1,000 mg/kg in mice. Thus, the compounds are quite safe. The medicines of the present invention contain, as their active components, compounds of claim 1 or their salts. The medicines of the invention may also contain optional components which are commonly used in formulating medicines. Examples of optional components are vehicles, bulking agents, binders, coating agents, sugar coats, stabilizers, disintegrants, colorants, lubricants, pH adjusters, solubilizers, dispersants, thickeners, isotonic agents, oils, and waxes. The medicines of the present invention are obtained by formulating one or more compounds of claim 1 or their salts together with pharmaceutically acceptable optional components by a routine method. The types of the medicines of the present invention are not particularly limited so long as they are legally permitted. For example, they may take the form of ordinary or sustained-release type drugs for oral administration, transdermal drugs, nasal drugs, rectal drugs, drip infusions, or Vorus' injections. Of these, peroral, injection, and nasal drugs are preferred. Suitable doses vary with the characteristics of patients such as their condition, age, body type, etc. In the case of oral administration, a dose of 10-1,000 mg compound/day is preferred, whereas in the case of parenteral administration, a dose of 1-500 mg compound/day is preferred, both doses applicable to an adult. The medicines are preferably administered several times daily, thereby make it possible to retain the constant concentration of active agents in blood. Examples: The present invention will next be described by way of examples, which should not be construed as limiting the invention. Example 1: In vitro binding inhibition assay against a cocaine derivative Male Wistar rats were decapitated. From each rat, striatum was immediately removed, and its wet weight was measured. The tissue of striatum was homogenized using a polytron together with a 10-fold amount of 50 mM Tris-HCl buffer (pH 7.4) while being cooled on ice. The homogenate was centrifugally separated (38,700 G, 20 minutes, 4°C), and the resulting pellet was suspended in a mixture of a 40-fold amount (based on the original tissue weight) of 50 mM Tris-HCl and 100 mM NaCl buffer (pH 7.4). The crude membrane sample suspended in the above-described mixture of 50 mM Tris HCl and 100 mM NaCl buffer (pH 7.4), a cocaine derivative [ 3 H]WIN35,428 (product of NEN, final concentration: 0.5 nM), and a test drug (final concentration: 1x10 -10 to 1x10 -5 M) were placed in an incubation tube. The contents were allowed to react for 2 hours on ice (0-4°C). Reaction was terminated by passing the contents through a glass filter (GF/B, product of Whatman) which had been immersed in 0.1% BSA solution for at least 40 minutes in advance while aspiration was carried out using a cell harvester, followed by washing three times with 5 ml of 50 mM Tris HCl buffer (pH 7.4). The filter and 10 ml of aquazol 2 (product of NEN) were placed in a vial and allowed to stand overnight. Radioactivity was measured using a liquid scintillation counter. Nonspecific binding amounts were determined as the binding amounts obtained in the presence of 10 µM (final concentration) of WIN35065-2 (product of Research Biochemical International, a cocaine derivative). Specific binding amounts were determined by subtracting the nonspecific binding amounts from the total binding amounts. Fifty(50)% inhibition concentrations were calculated using Hill plotting. The results are shown in Table 6. GBR12909 (product of Research Biochemical International) which is under development as a therapeutic agent for cocaine dependence, was used as a positive control. Compound No. 50% Inhibition concentration (nM) Compound 1 44.8 Compound 2 51.6 Compound 3 31.7 Compound 4 * 49.5 Compound 6 * 34.9 Compound 7 * 41.2 Compound 8 23.7 Compound 9 46.8 Compound 11* 196.7 Compound 13* 105.5 Compound 15 37.6 Compound 16 52.6 Compound 17 45.0 Compound 18 15.0 Compound 19* 72.2 Compound 20* 55.8 Compound 21 41.2 Compound 22* 306.5 Compound 23* 533.6 Compound 25* 23.7 GBR12909 89.1 WIN35,065-2 117.7 Cocaine 5101.7 Compounds marked with an asterisk are not recited in claim 1. From Table 6, it is found that compounds of claim 1 exhibit stronger binding inhibitory action than GBR12909. Moreover, compounds of claim 1 exhibit very strong binding inhibitory action which was not known to date. Considering that a compound of claim 1 and a cocaine derivative are in equilibrium in the test system employed and that a cocaine derivative is difficult to liberate after it is bound to a receptor, it is presumed that a compound of claim 1 cuts the linkage to a cocaine derivative and then binds itself to a receptor. In other words, the above data show that compounds of claim 1 are useful for the treatment of patients having narcotic dependence. Example 2: Ex vivo binding inhibition assay To each male Wistar rat, 30 mg/kg of compound 15 was intraperitoneally administered. Thirty minutes after administration, rats were decapitated. From each rat, striatum was immediately removed, and its wet weight was measured. The tissue of striatum was homogenized using a polytron together with a 10-fold amount of 50 mM Tris-HCl buffer (pH 7.4) while being cooled on ice. The homogenate was centrifugally separated (20,000 G, 20 minutes, 4°C), and the resulting pellet was suspended in a mixture of a 20-fold amount (based on the original tissue weight) of 50 mM Tris-HCl and 100 mM NaCl buffer (pH 7.4). The crude membrane sample suspended in the above-described mixture of 50 mM Tris-HCl and 100 mM NaCl buffer (pH 7.4) and a cocaine derivative [ 3 H]WIN35,428 (product of NEN, final concentration: 0.5 nM) were placed in an incubation tube. The contents were allowed to react for 2 hours on ice (0-4°C). Reaction was terminated by passing the contents through a glass filter (GF/B, product of Whatman) which had been immersed in 0.1% BSA solution for at least 40 minutes in advance while aspiration was carried out using a cell harvester, followed by washing three times with 5 ml of 50 mM Tris HCl buffer (pH 7.4). The filter and 10 ml of aquazol 2 (product of NEN) were placed in a vial and allowed to stand overnight. Radioactivity was measured using a liquid scintillation counter. Nonspecific binding amounts were determined as the binding amounts obtained in the presence of 10 µM (final concentration) of WIN35065-2 (product of Research Biochemical International, a cocaine derivative). Specific binding amounts were determined by subtracting the nonspecific binding amounts from the total binding amounts. Control accounts for the sole use of a saline solution administered to rats intraperitoneally. As a result, the binding inhibitory ratio in the control group was 0%, and the ratio in the group of compound 15 was 86.1%. Thus, the compound of the present invention exhibited excellent in vivo binding inhibitory action on cocaine as was exhibited ex vivo . Moreover, in view that the compound was pre-administered in this experiment, it is apparent that the compound is useful as a preventive drug for narcotic dependence. Examples 3 - 4 (Formulation examples): The following components were measured and placed in a Grad granulator and mixed at a low speed. Thereafter, a 5-fold amount of an aqueous 50% ethanol solution was sprayed portionwise thereto, and granulated at a high speed. The resulting granules were dried with air (40°C) stream for 48 hours, and were passed through a sieve to obtain granules. (Components) (parts by weight) Crystalline cellulose 38 Lactose 40 Hydroxypropylcellulose 10 Hydrochloric acid salt of compound 1 10 Aluminum stearate 2 (Components) (parts by weight) Crystalline cellulose 38 Lactose 40 Hydroxypropylcellulose 10 Oxalic acid salt of compound 2 5 Citric acid salt of compound 3 5 Aluminum stearate 2 Example 5 (Formulation example): The following components were dissolved at 80°C, placed in a mold, cooled, and removed from the mold, to obtain suppositories. (Components) (parts by weight) Vaseline 20 Suppository base G 70 Compound 4 10 Example 6 (Formulation example): Compound 1 (1 g) was subjected to liquid-liquid extraction using an aqueous saturated sodium hydrogencarbonate solution (100 ml) and diethyl ether (100 ml). The ether layer was collected and washed with water. The solvent was evaporated to obtain compound 1 in the free state. A portion (100 mg) of the compound was measured and placed in a 20-ml aerosol container can. A nozzle was attached to the container, after which the container was sealed. Flon gas was injected into the container to obtain a nasal agent. Example 7 (Formulation example): The following components were heated and kneaded with a kneader, and cooled to obtain a transnasal composition. (Components) (parts by weight) Vaseline 80 Liquid paraffin 9 Phosphatidyl choline 1 Compound 6 10 As described above, the narcotic antagonists of the present invention have potent narcotic antagonizing activities, and therefore, they are very useful in the prevention and treatment of narcotic dependence due to cocaine, for example.

Claims: Use of a compound selected from the group consisting of 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[bis(4-fluorophenyl)methyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-benzylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-methoxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-[3-(4-fluorophenylamino)-2-hydroxypropyl]piperazine · 2HCl, (-)-1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, (+)-1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, 1-[4,4-bis(4-fluorophenyl)butyl]-4-(2-hydroxy-3-(4-pyridylamino)propyl]piperazine · 2C 4 H 4 O 4 , 1-[3,3-bis(4-fluorophenyl)propyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl, and 1-[5,5-bis(4-fluorophenyl)pentyl]-4-(2-hydroxy-3-phenylaminopropyl)piperazine · 2HCl for the manufacture of narcotic antagonists or medicaments for the prevention and treatment of narcotic dependence. Use as defined in Claim 1, wherein the narcotic is one or more members selected from the group consisting of cocaine and/or its analogs.

Inventors: HARADA MARIKO, INAZU MASATO, MASUDA TOMOKO, HARADA, MARIKO, INAZU, MASATO, MASUDA, TOMOKO, Harada, Mariko, c/o Pola Chem. Ind., Inc., Inazu, Masato, c/o Pola Chem. Ind., Inc., Masuda, Tomoko, c/o Pola Chem. Ind., Inc.
Applicants: POLA CHEM IND INC, POLA CHEMICAL INDUSTRIES INC
Application year: 1996
Main classification: A61K31
IPC codes: A61K31, C07D295, A61P25