Use of an agent for the manufacture of a medicament for the treatment of liver disease

Abstract: A remedy for hepatic diseases, containing beraprost or a pharmacologically acceptable salt thereof as the active ingredient, which has an excellent activity of treating various hepatic diseases and is safe, chemically stable and orally administrable.

Description: TECHNICAL FIELD This invention relates to an agent for treating hepatic diseases which is useful for treating various hepatic diseases. BACKGROUND ART It is well-known that liver is an important organ which controls the metabolism in the body. It is said that as many as 40,000 people die of hepatic diseases in Japan in a year. Hepatic diseases such as hepatonecrosis, fatty liver, disorders of bile secretion, and cirrhosis are caused by the fact that the liver is acutely or chronically disordered by various factors such as alcohol, lack of nutrients, infection by viruses, chemical toxins and the like. At present, no drug which exhibits prominent pharmacological effect for the treatment and prophylaxis of these hepatic diseases when orally administered has beep discovered. EP A 0 232 776 discloses PGI 2 derivatives exhibiting excellent in vivo duration and activities. The disclosed compounds are said to have a strong inhibiting effect on platelet aggregation, and therefore these compounds are said to be therapeutically useful for various diseases, i. a., for liver diseases. As a further effect, uterine contacting activity is described. DISCLOSURE OF THE INVENTION The object of the present invention is to provide an agent for treating hepatic diseases, which has excellent effect for curing hepatic diseases, which is stable, which can be not only parenterally administered but also orally administered, and which is safe. The present inventors made extensive studies for developing an agent for treating hepatic diseases having excellent effectiveness and practicality to discover that stable beraprost has a prominent effect for inhibiting the reduction and promoting the functions of the liver, thereby completing the present invention. That is, the present invention provides the use of an agent for the manufacture of a medicament for treating hepatic diseases comprising as an effective ingredient beraprost or a pharmaceutically acceptable salt thereof. The agent for the manufacture of a medicament for treating hepatic diseases according to the present invention has excellent curing effect of various hepatic diseases and is safe. Further, it is chemically stable, so that it can be orally administered. BEST MODE FOR CARRYING OUT THE INVENTION The compound name of beraprost which is used as an agent for inhibiting metastasis of malignant tumors according to the present invention is (±)-(1R*,2R*, 3aS*,8bS*)-2,3,3a,8b-tetrahydro-2-hydroxy-1-[(E)-(3S*)-3-hydroxy-4-methyl-1-octene-6-inyl]-1H-cyclopenta[b]benzofuran-5-butyric acid. This compound has the following structure. Beraprost is described in Japanese Laid-open Patent Application (Kokai) Nos. 57-32277, 57-144276 and 58-124778 and the like as a PGI 2 derivative having a skeleton in which the exoenol moiety characteristic to beraprost is converted to inter-m-phenylene structure. However, it is not known that beraprost has an activity to cure hepatic diseases. The beraprost which is an effective ingredient of the agent of the present invention includes not only racemic form, but also d-form and l-form. Beraprost can be produced by, for example, the method described in the above-mentioned Japanese Laid-open Patent Application (Kokai) No. 58-124778. The salts of beraprost include any pharmaceutically acceptable salts including alkaline metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; ammonium salt; primary, secondary and tertiary amine salts; and basic amino acid salts. When orally or parenterally administered, beraprost exhibits prominent effect for inhibiting the reduction and promoting the functions of the liver. More particularly, the agent for treating hepatic diseases according to the present invention is effective for treating acute and chronic hepatic diseases such as fatty liver, alcoholic hepatitis, toxic hepatic disorders, congestive liver, disorders of bile secretion, stagnation hepatic disorders, ischemic hepatic disorders, hepatic insufficiency, fulminating hepatitis and cirrhosis. Further, the agent is also effective for promoting functions of the liver suffering from hepatic disorders after surgery, viral hepatic disorders and liver cancer. The agent is also effective for the protection of the liver during transplantation and for promoting the functions of the liver after transplantation. The dose of administration of the compound differs depending on the type and degree of the disease to be treated. In cases where acute or chronic hepatic diseases such as fatty liver, alcoholic hepatitis, toxic hepatic disorders, disorders of bile secretion, and cirrhosis, beraprost is administered in a dose of 0.01 - 100 mg/body and 1 - 3 times a day. Although beraprost or a salt thereof alone may be administered, the agent for treating hepatic diseases according to the present invention may also be administered in the form of solid containing the additives described below. Examples of the additives include vehicles such as starches, lactose, sucrose, glucose, mannitol, calcium carbonate, calcium sulfate and the like; binding agents such as starches, dextrin, gum arbicae, tragacanth, methyl cellulose, gelatin, polyvinylpyrrolidone, polyvinyl alcohol or the like; a disintegrator such as starches, polyvinylpyrrolidone, crystalline cellulose and the like; lubricants such as magnesium stearate, talc and the like; coloring agents; and perfumes. The formulation may be in the form of tablets, sugar-coated tablets, powder, granules, troches, capsules, balls and syrups. For parenteral administration, the composition may be formulated into an aqueous sterilized solution. The solution may contain other solutes such as sodium chloride or glucose in an amount sufficient to make the solution isotonic. Since the agent for treating hepatic diseases according to the present invention has a stable chemical structure, there is no difficulty in formulating the compound. Thus, in addition to the above-described formulations for oral administration, the compound may easily be formulated in the form of various solutions for injection and suppositories. Example The invention will now be described in more concretely by way of examples thereof. However, the present invention is not restricted to the examples. Example 1 Using Sprague-Dawley (hereinafter referred to as "SD" for short) male rats of 7 weeks old, the effectiveness of beraprost against the hepatic disorder induced by carbon tetrachloride was tested employing two administration routes, that is, oral and intraperitoneal administrations. Each group consisted of 6 rats. The test compound was sodium salt of beraprost. To the rats which had been fasted for 24 hours, the test compound was administered. One hour after the administration, 12.5% carbon tetrachloride solution in olive oil was administered in a dose of 2 ml/kg. To the rats to which the test compound was orally administered, the carbon tetrachloride solution was intraperitoneally administered. To the rats to which the test compound was intraperitoneally administered, the carbon tetrachloride solution was orally administered. After the administration of the carbon tetrachloride solution, the rats were fasted for 24 hours, and the glutamic acid-oxalic acid transaminase (hereinafter referred to as "GOT" for short) level in serum was measured. As a control group, one group was treated in the same manner as described above except that the sodium salt of beraprost was not administered. The results are shown in Table 1. As shown in Table 1, in the groups to which sodium salt of beraprost was administered, significant decrease in GOT was observed. Thus, it was confirmed that hepatic disorder is improved by administration of beraprost. Example 2 Using SD male rats of 7 weeks old, the effectiveness of beraprost by oral administration against the hepatic disorder induced by D-galactosamine was tested. As the test compound, sodium salt of beraprost was used. The test compound was administered in a dose of 0.3 mg/kg per each time at one hour before and 6 hours after the administration of D-galactosamine. D-galactosamine was subcutaneously administered in a dose of 1 g/kg. Forty eight hours after the administration of D-galactosamine, GOT level and glutamic acid-pyruvic acid transaminase (hereinafter referred to as "GPT" for short) level in serum, and the content of triglyceride in the liver were measured. As a control group, one group was treated in the same manner as described above except that sodium salt of beraprost was not administered. As a non-treated group, one group did not receive D-galactosamine. The results are shown in Table 2. As shown in Table 2, significant decrease in GOT, GPT and the amount of triglycerides in the liver were observed in the test group (the group to which the test compound was administered) when compared with the control group. Thus, it was confirmed that beraprost has an activity to improve hepatic disorders. Example 3 Using SD male rats of 7 weeks old, each group consisting of 6 rats, the effectiveness of beraprost by oral administration against the increase in the lipid peroxide level in the blood induced by carbon tetrachloride was tested. As the test compound, sodium salt of beraprost was used. To the rats which had been fasted for 24 hours, 12.5% carbon tetrachloride solution in olive oil was intraperitoneally administered in a dose of 2 ml/kg. After the administration of the carbon tetrachloride solution, the rats were fasted for 24 hours and then the levels of lipid peroxide, GOT and GPT in serum were measured. The test compound was administered one hour before (Test Group 1) or 6 hours after (Test Group 2) the administration of the carbon tetrachloride solution. As a control group, one group was treated in the same manner as described above except that the sodium salt of beraprost was not administered. As a non-treated group, one group did not receive carbon tetrachloride. The results are shown in Table 3. As shown in Table 3, by the administration of the test compound one hour before or 6 hours after the administration of the disorder-causing substance, significant decrease in GOT, GPT and lipid peroxide level in the blood was observed. Thus, it was confirmed that beraprost has an activity to improve hepatic disorders. Particularly, since a significant effect for improving hepatic disorder was observed even when the compound was orally administered 6 hours after the administration of the disorder-causing substance, it was shown that the compound has a strong effect for improving hepatic disorders. Example 4 Using SD male rats of 8 - 10 weeks old, the effectiveness of beraprost by oral administration against the disorder caused by liver ischemia-recirculation was tested. As the test compound, sodium salt of beraprost was used. The test compound was administered 30 minutes before the induction of ischemic liver. The doses of the administered test compound were as shown in Table 4. Ischemic liver was prepared by ventrotomy under anesthesia and closing the hepatic artery in the outer left leaf and the portal vein with clips. One hour after the clipping, the clips were removed to reopen the vessels. Two hours after the recirculation, the GPT level in serum was measured to evaluate the degree of disorder. As a control group, one group was treated in the same manner as described above except that distilled water was administered in place of sodium salt of beraprost. The results are shown in Table 4. As shown in Table 4, by the administration of sodium salt of beraprost, decrease in GPT level in serum was observed. Thus, it was confirmed that beraprost has an activity to improve the hepatic disorder caused by ischemia of the liver. Example 5 [Acute Toxicity Test] Acute toxicity test was carried out using rats. LD 50 values of the compound for each administration route and sex are shown in Table 5. As for the pathological symptoms, the main symptoms which were common to male and female and to all of the administration routes were, in the cases wherein the mice were killed, slight to medium congestion in lung, slight to medium bleeding in stomach glands and slight small intestine catarrh. Thus, it was clarified that side effects are observed only at very high dose. Example 6 Tablets according to the present invention were prepared according to the prescription shown in Table 6. INDUSTRIAL APPLICABILITY The agent for treating hepatic diseases according to the present invention exhibits effectiveness for the treatment and prophylaxis of various hepatic diseases. Further, it is chemically stable. Therefore, it can be used for treating and preventing hepatic disorders by systemic administration.

Claims: The use of an agent comprising beraprost or a pharmaceutically acceptable salt thereof as an effective ingredient for the manufacture of a medicament for treating hepatic diseases. The use of beraprost or a pharmaceutically acceptable salt thereof for the manufacture of a composition comprising an effective amount of beraprost or a pharmaceutically acceptable salt thereof in a pharmaceutically acceptable carrier for treating hepatic diseases.

Inventors: NISHIO SHINTARO, UENO SHINYA, NISHIO, SHINTARO, UENO, SHINYA
Applicants: TORAY INDUSTRIES, TORAY INDUSTRIES, INC.
Application year: 1992
Main classification: A61K31
IPC codes: A61K31, C07C405