Pharmaceutical compositions of heterocyclic angiotensin-II antagonists and oily substances for oral use and method of preparing them

Abstract: A pharmaceutical composition for oral use comprising an effective amount of a compound of the formula (I) having antagonistic action to angiotensin II (wherein the ring W is an optionally substituted N-containing heterocyclic residue; R 3 is a group capable of forming an anion or a group convertible thereinto; X is a direct bond or a spacer having an atomic length of two or less between the phenylene group and the phenyl group; and n is an integer of 1 or 2) and an oleaginous substance having a lower melting point, and a method for preparing a pharmaceutical composition for oral use comprising an effective amount of a compound of the formula (I) and an oily substance having a lower melting point, which comprises admixing the compound of the formula (I) with an oily substance having a lower melting point and then subjecting the mixture to molding.

Description: This invention relates to orally administrable pharmaceutical compositions capable of suppressing decomposition of the active component contained therein and maintaining excellent stability with days and method of preparing them. More specifically, the present invention relates to a pharmaceutical composition for oral use comprising (A) an effective amount of a compound of the formula (I) having antagonistic action to angiotensin II wherein in the N-containing heterocyclic residue represented by the formula: a represents nitrogen atom; b and c independently represent optionally substituted carbon atoms; which N-containing heterocyclic residue may be substituted, besides Y-R 1 ; R 1 is hydrogen or an optionally substituted hydrocarbon residue; Y is a bond, -O-, -S(O)m-, wherein m denotes 0, 1 or 2, or -N(R 4 )-, where R 4 is hydrogen or an optionally substituted alkyl group; R 3 is tetrazolyl; X is a direct bond between the phenylene group and the phenyl group; n is 1, which has antagonistic action to angiotensin II and (B) an oily substance selected from hydrocarbon, higher fatty acid selected from capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidinic acid, behenic acid, lignoceric acid, cerotic acid and a mixture of them, higher alcohol selected from lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, aralkyl alcohol and a mixture of them, fatty acid ester of polyhydric alcohol, higher alcohol ether of polyhydric alcohol selected from ethers formed by etherification of a polyhydric alcohol with a higher fatty acid alcohol, selected from cetyl alcohol, stearyl alcohol, oleyl alcohol, octyl alcohol and decyl alcohol, polyoxyethylene lauryl alcohol ether, polyoxyethylene cetyl alcohol ether, polyoxyethylene stearyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene octyl alcohol ether, polyoxyethylene decyl alcohol ether, polyoxypropylene polyoxyethylene cetyl alcohol ether, polyoxypropylene polyoxyethylene stearyl alcohol ether, polyoxypropylene polyoxyethylene oleyl alcohol ether, polyoxypropylene polyoxyethylene octyl alcohol ether and polyoxypropylene polyoxyethylene lauryl alcohol ether and a polymer or copolymer of alkylene oxide, which is effective for the therapy of, among others, hypertension and congestive heart failure, and to a method of preparing the composition. BACKGROUND OF THE INVENTION In the field of therapy of hypertension, angiotensin II (AII) receptor antagonist (AIIA) has attracted attention as an effective agent for the therapy of hypertension following angiotensin I converting enzyme (ACE) inhibitors. A compound of the formula (I), for example, benzimidazole-7-carboxylic acid and derivatives thereof having a strong anti-AII action (cf. EP-A 0 425 921 and EP-A 0 459 136) are considered to have, for example, the following advantages as compared with ACE inhibitors. 1) It has been known that there are a series capable of producing AII, which are not in the series of ACE. For example, benzimidazole-7-carboxylic acid and derivatives thereof also inhibit the action of this AII which is not dependent on ACE, and therefore it may well be that these compounds exhibit a stronger and more effective hypotensive action than that of ACE inhibitors. 2) Since benzimidazole-7-carboxylic acid and derivatives thereof do not enhance the action of bradykinin observed in ACE inhibitors, they are less possible to cause coughing as a side effect. EP-A-0 445 811 discloses nitrogen-containing heterocyclic compounds which have angiotensin II antagonist activity and which have a structure different to the structure of the compounds employed in the pharmaceutical compositions of the present invention.EP-A-0 442 473 discloses pyrimidinedione derivatives possessing angiotensin II antagonistic activity. The structure of these compounds is different to the structure of the compounds employed in the pharmaceutical compositions of the present invention. EP-A-0 430 300 discloses xanthine derivatives possessing angiotensin II antagonist activity. No solid pharmaceutical compositions comprising these compounds and an oily substance are disclosed.EP-A-0 411 507 discloses pyrazole derivatives potent in angiotension II antagonism. The structure of these compounds is different to the structure of the compounds employed in the pharmaceutical compositions of the present invention. EP-A-0 420 237 discloses biphenylmethane derivatives and pharmacological compositions containing the same. EP-A-0 435 827 discloses diaza compounds and pharmaceutical preparations containing these compounds. However, none of these documents mentions any problem regarding the stability of the active ingredient or that such problem could be solved by adding specific oily substances.EP-A-0 344 795 relates to the problem that disodium adenosine triphosphate (ATP-2Na), in the solid form, is unstable under high temperature and/or high humidity conditions. Stable pharmaceutical compositions containing ATP-2Na are obtained by adding a low-melting fat- or oillike substance.DE 2 251 199 discloses preparations comprising pyrazolone compounds. The pyrazolone compounds are tabletted by adding polyethylene glycole 2.000-20.000 and optionally low amounts of lubricant agents. OBJECT OF THE INVENTION However, while the compounds of the formula (I) having antagonistic action to angiotensin II, for example, benzimidazole-7-carboxylic acid and derivatives thereof, useful as therapeutic agent of hypertension are stable against temperature, moisture and light when they are alone in the solid state, when they are prepared into tablets of a formulation incorporated with other ingredients, it has been observed that lowering of the content of the active ingredient is apt to be enhanced with the lapse of day due to deformation of crystals caused by, for example, pressure, abrasion and heat, applied in the step of granulation or molding under elevated pressure in the course of preparation. While research and development of the compound of the formula (I) (hereinafter sometimes called "active component") thereof as therapeutic agent of hypertension have been conducted, problems in respect of the stability in the course of preparation are not satisfactorily solved yet. Especially, no practical technique for improving the stability of a benzimidazole-7-carboxylic acid and derivatives thereof contained in the preparation, by sufficiently suppressing decomposition of the active component with the lapse of day, the decomposition being observed in the case where the active component is formulated into a solid preparation such as tablets, has been established yet. Thus, the object of this invention is to provide stabilized preparations of the compound of the formula (I) having antagonistic action to angiotensin II. Furthermore, the present invention aims at sufficiently practical method of stabilization from the economical viewpoint as well, without resorting to a method inevitably requiring the rise of cost, such as that involving use of an excess amount of the active component or extremely minimizing the moisture content. The present invention is also to heighten the value of finished products by prolonging the period expiration through improved stability of the compositions. In view of the circumstances described as above, the present inventors attempted various means of general use in order to realize the stabilization of compositions containing the compound of the formula (I) having antagonistic action to angiotensin II. In no compositions prepared thus above, however, was found a satisfactorily practical stabilizing effect. The present inventors further continued various investigations, and unexpectedly found that, by incorporating an oily substance having a low melting point into a formulation containing the compound of the formula (I) having antagonistic action to angiotensin II, decomposition of the active component is remarkably suppressed to afford a stable composition, and further investigations were conducted repeatedly to accomplish the present invention. SUMMARY OF THE INVENTION An object of the present invention is to provide (1) a pharmaceutical composition for oral use comprising (A) an effective amount of a compound of the formula (I) having antagonistic action to angiotensin II wherein in the N-containing heterocyclic residue represented by the formula: a represents nitrogen atom; b and c independently represent optionally substituted carbon atoms; which N-containing heterocyclic residue may be substituted, besides Y-R 1 ; R 1 is hydrogen or an optionally substituted hydrocarbon residue; Y is a bond, -O-, -S(O)m-, wherein m denotes 0, 1 or 2, or -N(R 4 )-, where R 4 is hydrogen or an optionally substituted alkyl group; R 3 is tetrazolyl; X is a direct bond between the phenylene group and the phenyl group; n is 1, which has antagonistic action to angiotensin II and (B) an oily substance selected from hydrocarbon, higher fatty acid selected from capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidinic acid, behenic acid, lignoceric acid, cerotic acid and a mixture of them, higher alcohol selected from lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, aralkyl alcohol and a mixture of them, fatty acid ester of polyhydric alcohol, higher alcohol ether of polyhydric alcohol selected from ethers formed by etherification of a polyhydric alcohol with a higher fatty acid alcohol, selected from cetyl alcohol, stearyl alcohol, oleyl alcohol, octyl alcohol and decyl alcohol, polyoxyethylene lauryl alcohol ether, polyoxyethylene cetyl alcohol ether, polyoxyethylene stearyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene octyl alcohol ether, polyoxyethylene decyl alcohol ether, polyoxypropylene polyoxyethylene cetyl alcohol ether, polyoxypropylene polyoxyethylene stearyl alcohol ether, polyoxypropylene polyoxyethylene oleyl alcohol ether, polyoxypropylene polyoxyethylene octyl alcohol ether and polyoxypropylene polyoxyethylene lauryl alcohol ether and a polymer or copolymer of alkylene oxide, and (2) further object of the present invention is to provide a method for preparing a pharmaceutical composition for oral use as defined above, which comprises admixing the compound of the formula (I) with an oleaginous substance having a lower melting point and then subjecting the mixture to molding. DETAILED DESCRIPTION OF THE INVENTION Referring to the formula (I), R 3 is tetrazolyl. X is a chemical bond between the phenylene group and the phenyl group. n denotes an integer of 1. The N-containing heterocyclic residues are specifically defined as follows. Incidentally, in the following formulae, R 1 is hydrogen or an optionally substituted hydrocarbon residue; and Y is a bond, -O-, -S(O)m- (where m denotes 0, 1 or 2) or -N(R 4 )- (where R 4 is hydrogen or an optionally substituted alkyl group). Among them, R 1 is preferably a lower (C 1-5 ) alkyl (preferably a lower (C 2-3 ) alkyl) optionally substituted with hydroxyl group, amino group, halogen or a lower (C 1-4 ) alkoxy group; and Y is preferably a bond, -O-, -S- or -N(R 4 )- (wherein R 4 stands for hydrogen or a lower (C 1-4 ) alkyl). Examples of include the following: wherein h and h' each shows >CH 2 , >=O, or >=S. Among the compound represented by the formula (I) having antagonistic action to angiotensin II, those with a crystalline structure having the melting point of 100 to 200°C, especially 130 to 180°C are conveniently employed from the viewpoint of stability. Among the oily substances, any one can be used, so long as it is oily and has the melting point of about 20 to 90°C, preferably 20 to 60°C and exerts no undesirable influence on the active component. The above oily substances may be more evenly admixed with the active component in preparation of pharmaceutical compositions for oral use of the present invention so that more stable compositions are produced, as compared with use of an oily substance having a higher melting point. Furthermore, among them, any one may be soluble or unsoluble in water. Here, an example of the oily substances which is soluble in water is a polymer of alkylene oxide, as mentioned below. Examples of these substances include hydrocarbon, higher fatty acid, higher alcohol, fatty acid ester of polyhydric alcohol, higher alcohol ether of polyhydric alcohol, and polymer or copolymer of alkylene oxide. Among them, fatty acid ester of polyhydric alcohol, higher alcohol ether of polyhydric alcohol, polymer or copolymer of alkylene oxide, especially polymer of alkylene oxide, are preferably employed. Examples of hydrocarbon include C 17-50 n-alkane such as n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tricosane, n-tetracosane, n-pentacosane, n-triacontane, n-pentatriacontane, n-tetracontane and n-pentacontane, as well as a mixture of them (petrolatum, paraffin wax, microcrystalline wax, etc.). Higher fatty acids are capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidinic acid, behenic acid, lignoceric acid, cerotic acid and a mixture of them. Higher alcohols are lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, aralkyl alcohol and a mixture of them. Examples of fatty acid ester of polyhydric alcohol include esters formed by esterification of an alcohol having two or more hydroxyl groups in the molecule (for example, alkylene glycols such as ethylene glycol and propylene glycol; polyalkylene glycols such as polyethylene glycol, polypropylene glycol or copolymers of them; sugars such as sorbitol, sucrose and raffinose; intramolecular dehydrates such as 1,5-sorbitan, 1,4-sorbitol and 3,6-sorbitan; glycerin, diethanolamine, pentaerythritol, etc.) with a fatty acid (for example, acetic acid, propionic acid, butyric acid, pelargonic acid, capric acid, undecyclic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, undecylenic acid, oleic acid, elaidic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, stearolic acid, etc.), more specifically, sorbitan fatty acid esters having a molecular weight of 400 to 900, such as sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan sesquioleate or sorbitan monopalmitate; polyoxyalkylene sorbitan fatty acid esters having a molecular weight of 1000 to 1500, such as polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate or polyoxyethylene sorbitan tripalmitate; polyoxyalkylene sorbitol fatty acid esters, such as polyoxyethylene sorbitol hexastearate, polyoxyethylene sorbitol hexaoleate, polyoxyethylene sorbitol tristearate or polyoxyethylene sorbitol tetralaurate; polyoxyalkylene sorbitol bees wax derivatives such as polyoxyethylene sorbitol bees wax derivatives; polyoxyalkylene hydrous lanolin derivatives such as polyoxyehtylene hydrous lanolin derivatives; propylene glycol fatty acid esters having a molecular weight of 200 to 700 such as propylene glycol monopalmitate, propylene glycol monostearate, propylene glycol dilaurate, propylene glycol dimyristate, propylene glycol dipalmitate or propylene glycol distearate; alkylene glycol fatty acid esters including ethylene glycol fatty acid ester having a molecular weight of 500 to 1200, such as ethylene glycol monolaurate, ethylene glycol palmitate, ethylene glycol margarate, ethylene glycol stearate, ethylene glycol dilaurate, ehtylene glycol dimyristate, ethylene glycol dipalmitate or ethylene glycol dimargarate; polyoxyethylene castor oil derivatives having a molecular weight of 3500 to 4000, such as polyoxyethylene castor oil derivatives; polyoxyalkylene fatty acid esters having a molecular weight of 1900 to 2200, such as polyoxyethylene stearate, polyoxyethylene oleate, polyoxyethylene palmitate or polyoxyethylene linolate; glycerine monofatty acid esters having a molecular weight of 300 to 600, such as glycerine monoacetate, glycerine monopropionate, glycerine monostearate, glycerine monooleate, glycerine monopalmitate or glycerine monolinolate; and sucrose fatty acid esters having a molecular weight of 400 to 1300, such as sucrose monolaurate, sucrose monomyristate, sucrose monopalminate, sucrose monostearate, sucrose trimyristate, sucrose tripalmitate or sucrose tristearate. Higher alcohol esters of polyhydric alcohol are ethers formed by etherification of a polyhydric alcohol (set forth as alcohol components of the fatty acid ester of polyhydric alcohol mentioned above) with a higher fatty acid alcohol (for example, cetyl alcohol, stearyl alcohol, oleyl alcohol, octyl alcohol or decyl alcohol), more specifically, polyoxyethylene higher alcohol ethers such as polyoxyethylene lauryl alcohol ether, polyoxyethylene cetyl alcohol ether, polyoxyethylene stearyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene octyl alcohol ether or polyoxyethylene decyl alcohol ether; and polyoxypropylene polyoxyethylene higher alcohol ethers such as polyoxypropylene polyoxyethylene cetyl alcohol ether, polyoxypropylene polyoxyethylene stearyl alcohol ether, polyoxypropylene polyoxyethylene oleyl alcohol ether, polyoxypropylene polyoxyethylene octyl alcohol ether or polyoxypropylene polyoxyethylene lauryl alcohol ether are generally used. As the polymer of alkylene oxide, use is made of those having a molecular weight of 1,000 to 10,000 (e.g. polyethylene glycol 6000). Examples of the alkylene oxide include ethylene oxide, propylene oxide, trimethylene oxide and tetrahydrofuran (preferably ethylene oxide). As the copolymer of alkylene oxide, use is made of copolymers of two or more species of the above-mentioned alkylene oxides, having a molecular weight of 1,000 to 10,000. These substances may be used singly or as a mixture of two or more of them. These substances are added to the active component in a solid or liquid state. The present invention is more conveniently applied to a solid composition (e.g. granules and tablets, preferably tablets) prepared by molding (e.g. granulation or molding under elevated pressure). Preparation of a solid composition of the present invention is usually conducted by incorporating such an oleaginous substance having a lower melting point into the active component, followed by subjecting the mixture to molding. The incorporation is conducted by a method conventionally employed in the field of pharmaceutical preparations, for example, mixing, massing, kneading, sieving and stirring. For example, an oily substance having a lower melting point is directly added to the active component and to make a mixture (addition in powdery state), or a solvent is added the mixture, followed by conventional granulating and drying. Alternatively, an oily substance having a lower melting point is dissolved in an adequate solvent, then the solution is mixed with the active component, followed by conventional kneading, granulating and drying (addition in liquid state). Further, a liquid material containing an oleaginous substance having a lower melting point and a liquid material containing the active component can be independently sprayed onto a powdery material such as an excipient, followed by mixing the resultant material. In the case of "addition in liquid state", any solvent which does not exert undesirable influence on the active component, for example, water, dimethylformamide, acetone, ethanol, propyl alcohol, isopropyl alcohol, butyl alcohol, methylene chloride and trichloroethane, can be employed. After completing the blending, the material is subjected to a conventional molding process under elevated pressure to prepare tablets containing the active component. The molding under elevated pressure means that a material is compressed under elevated pressure into a desired form, and it refers to, most generally, tabletting. Incorporation of such an oily substance having a lower melting point as described above serves to minimize crystalline disorder possibly caused in the steps of kneading, granulating and molding under elevated pressure, and is considered to further serve advantageously to improve the moldability and to lower the pressure to be elevated. And, in the method of preparing the composition of this invention, a variety of additives to be employed for solid compositions can be added in an adequate step. These additives are exemplified by excipients such as crystalline cellulose (e.g. Avicel PH 101 (manufactured by Asahi Chemical Industry Co., Ltd.)), carboxymethyl cellulose calcium, corn starch, wheat starch, lactose, sucrose, glucose, calcium sulfate, calcium phosphate or sodium chloride, binders such as gum arabic, gelatin, methyl cellulose, polyvinyl pyrrolidone, hydroxypropyl cellulose (hereinafter sometimes abbreviated as HPC) or hydroxypropylmethyl cellulose, lubricants such as magnesium stearate, talc, synthetic aluminum silicate, sodium lauryl sulfate, boric acid, magnesium oxide or paraffin, colorants, flavoring agents, odor-improving agents, etc. Incidentally, in the case of using such a crystalline compound whose specific gravity is relatively small as the formula (V), it is desirable to have the compound dispersed in advance in a thick liquid containing such a binder as HPC and water. Furthermore, the composition of this invention may be prepared into coated tablets as well. The coating may be conducted by a per se known method. As coating agents, use is made of conventional ones (e.g. hydroxylpropylmethyl cellulose, hydroxylpropyl cellulose, methyl cellulose and polyvinyl pyrrolidone), and as auxiliary agents for coating, use is made of, for example, polyethylene glycol 6000, polysorbate (e.g. Tween ® 80), titanium oxide, and pigments such as red iron oxide. In the stabilized pharmaceutical composition for oral use in the present invention prepared by admixing an oily substance having a lower melting point with the active component, the amount of the oleaginous substance is 0.005 to 0.15 weight, preferably 0.01 to 0.1 weight, more preferably 0.02 to 0.05 weight per 1 weight of the composition, and the amount of the active component is 0.001 to 0.15 part by weight, preferably 0.007 to 0.09 part by weight, more preferably 0.015 to 0.04 part by weight per 1 part of the composition by weight. Also, the stabilized pharmaceutical compostition for oral use in the present invention is desirable to disintegrate in an aqueous solution with 30 minutes. In the orally administrable pharmaceutical composition thus prepared by incorporating an oily substance having a lower melting point into the active component, decomposition with day possibly caused by compression can be suppressed to provide a stable composition. In the case of using the pharmaceutical composition of this invention for the therapy of hypertension, cardiac diseases, cerebral apoplexy or renal diseases of mammals (e.g. man, dog, rabbit or rat), it can be administered orally as tablets. The dosage ranges from about 1 to 50 mg, preferably from about 2 to 30 mg per day in terms of the active component (e.g. the compound of the formula (I) having antagonistic action to angiotensin II). For a more complete understanding of the instant invention, reference is made to the following illustrative examples. The examples are carried out with the compound of formula V or the compounds named in the specific example and thus are reference examples. Example 1 In a fluid-bed granulator (Powrex, FD-3S), in accordance with the following formulation, polyethylene glycol 6000 as the oleaginous substance having a lower melting point was mixed with other ingredients including the compound having antagonistic action to angiotensin II (the active component). Onto the mixture was sprayed an aqueous solution of hydroxypropyl cellulose as the binder, which was granulated and dried to give granules. To the granules was added carboxylmethylcellulose calcium and magnesium stearate, and the mixture was tabletted by a tablet machine (Kikusui Seisakusho, Correct 19K) using punches (7.0 mm in diameter) of bevelled edge at a weight of 130 mg under a pressure of 1.9*10 8 Pa (2.0 ton/cm 2 ). The tablets thus prepared were stored at 50°C or 40°C and subjected to stability test. Formulation Materials Sample Control A B the formula (V) 1.0 mg 1.0 mg Lactose 93.0 99.0 Corn starch 20.0 20.0 Polyethylene glycol 6000 6.0 - Hydroxypropyl cellulose 4.0 4.0 (water) (0.135 ml) (0.135 ml) Sub-total 124.0 mg 124.0 mg Carboxylmethylcellulose-calcium 5.6 5.6 Magnesium stearate 0.4 0.4 Total 130.0 mg 130.0 mg Results of stability test Item Sample Control A B At the initial time of test (hereinafter simply written as "initial") (100) (100) Residual ratio after storing at 50°C for 4 weeks 99.3 89.7 Residual ratio after storing at 40°C for 8 weeks 99.8 94.8 The stability test was conducted by determining the content of the formula (V) after storing the respective periods by liquid chromatography, and the residual ratios were shown by percent. As the control, the composition (B) containing no stabilizing agent (an oily substance having a lower melting point) was employed, and the test was conducted by comparing it with the composition (A) containing polyethylene glycol 6000 as the oily substance having a lower melting point. As is clear from the test results, the composition of this invention is excellent in stability as compared with the control. Example 2 In a fluid-bed granulator (Glatt WSG-15®), in accordance with the same formulation as in Example 1, polyethylene glycol 6000 as the oily substance having a lower melting point was dissolved in water, in which the formula (V) was dispersed, then the dispersion was sprayed on a powder mixture of lactose and corn starch. The resultant material was further sprayed with an aqueous solution of hydroxypropyl cellulose, which was granulated and dried to give granules. The granules were mixed with carboxylmethylcellulose calcium and magnesium stearate respectively, and the mixture was tabletted by a tablet machine using punches (7.0 mm in diameter) of bevelled edge at a weight of 130 mg under a pressure of 1.9*10 8 Pa (2.0 ton/cm 2 ). Test results of stability Item Sample Control A B Initial (100) (100) Residual ratio after storing at 50°C for one week 99.0 89.0 Residual ratio after storing at 40°C for 4 weeks 99.8 91.1 From the test results, it is understood that, in the composition of this invention, the formula (V) is remarkably stable as compared with that in the control. Example 3 In a fluid-bed granulator (Powrex FD-5S), in accordance with the same formulation as in Example 1, an aqueous solution of polyethylene glycol 6000 as the oily substance having a lower melting point was sprayed onto a powder mixture of lactose and corn starch. The resultant material was further sprayed with a dispersion of the formula (V) in an aqueous solution of hydroxypropyl cellulose, which was granulated and dried to give granules. The granules were mixed with carboxylmethylcellulose calcium and magnesium stearate respectively, and the mixture was tabletted by a tablet machine (Kikusui Seisakusho, Correct 19K) using punches of shallow concave (7.0 mm in diameter) at a weight of 130 mg under a pressure of 1.9*10 8 Pa (2.0 ton/cm 2 ). Further, in accordance with the following formulation of aqueous coating tablets, the aqueous coating (5 mg) was performed by Accelacoater (Manesty Co., Ltd., Great Britain) using hydroxypropylmethyl cellulose. Formulation Materials per tablet Core tablet 130.0 mg Hydroxypropylmethyl cellulose 3.50 mg Polyethylene glycol 6000 0.75 mg Titanium oxide 0.75 mg (water) (0.05 ml) Total 135.0 mg Results of stability test Item Sample Control A B Initial (100) (100) Residual ratio after storing at 50°C for 4 weeks 99.4 88.4 Residual ratio after storing at 40°C for 8 weeks 100.0 90.2 From the results of the test, it is understood that, in the composition of this invention, the formula (V) is remarkably stable as compared with that in the control. Example 4 In a granulator equipped with stirrer (Powrex, vertical granulator VG10), the formula (V) was dispersed in an aqueous solution of polyethylene glycol 6000 as the oily substance having a lower melting point and HPC. This dispersion was added to a powder mixture of lactose and corn starch, which was granulated and dried to give granules, followed by addition of carboxymethylcellulose calcium and magnesium stearate respectively. The mixture was tabletted by a tablet machine using punches of bevelled edge (7.0 mm in diameter) at a weight of 130 mg under a pressure of 1.9*10 8 Pa (2.0 ton/cm 2 ). Formulation Materials Sample Control A B the formula (V) 10.0 mg 10.0 mg Lactose 84.0 90.0 Corn starch 20.0 20.0 Polyethylene glycol 6000 6.0 - Hydroxypropyl cellulose 4.0 4.0 (water) (0.024 ml) (0.024 ml) Sub-total 124.0 mg 124.0 mg Carboxylmethylcellulose-calcium 5.6 5.6 Magnesium stearate 0.4 0.4 Total 130.0 mg 130.0 mg Results of stability test Item Sample Control A B Initial (100) (100) Residual ratio after storing at 50°C for 4 weeks 99.1 87.2 Residual ratio after storing at 40°C for 8 weeks 99.5 89.7 From the results of the test, it is understood that, in the composition of this invention, the formula (V) is remarkably stable as compared with that in the control. Example 5 In substantially the same manner as in Example 1, tablets were prepared under the formulation as shown in the following Table 1. These tablets were subjected to the test of stability in substantially the same manner as in Example 1. The results are shown in Table 2. Formulation Materials Samples Control A B C D E the formula (V) 1.0 mg 1.0 mg 1.0 mg 1.0 mg 1.0 mg Lactose 98.0 89.0 93.0 93.0 99.0 Corn starch 20.0 20.0 20.0 20.0 20.0 Stearyl alcohol 1.0 10.0 - - - Sucrose fatty acid ester - - 6.0 - - Sorbitan fatty acid ester - - - 6.0 - Hydroxy propyl cellulose 4.0 4.0 4.0 4.0 4.0 (Water) (0.135 ml) (0.135) (0.135) (0.135) (0.135) Sub-total 124.0 mg 124.0 124.0 124.0 124.0 Carboxymethyl cellulose calcium 5.6 5.6 5.6 5.6 5.6 Magnesium stearate 0.4 0.4 0.4 0.4 0.4 Total 130.0 mg 130.0 130.0 130.0 130.0 Results of stability test Item Samples Control A B C D E Initial (100) (100) (100) (100) (100) Residual ratio after storing at 50°C for 4 weeks 99.0 99.4 98.9 99.1 89.7 Residual ratio after storing at 40°C for 4 weeks 99.2 100.0 99.3 99.6 94.8 From the above test results, it is understood that the compostition of this invention in which an oily substance having a relatively low melting point is excellent in the stability of the formula (V) contained therein. Example 6 In substantially the same manner as in Example 1, tablets can be prepared under the formulations as shown in the following Table 3. Formulation Materials Samples A B C D 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid 1,0mg - - - 2-butyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid - 1.0 - - 1-(cyclohexyloxycarbonyloxy)ethyl 2-butyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate - - 1.0 - pivaloyloxymethyl 2-butyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]-methyl]benzimidazole-7-carboxylate - - - 1.0 Lactose 93.0 93.0 93.0 93.0 Corn starch 20.0 20.0 20.0 20.0 Polyethylene glycol 6000 6.0 6.0 6.0 6.0 Hydroxypropyl cellulose 4.0 4.0 4.0 4.0 (Water) (0.135ml) (0.135ml) (0.135ml) (0.135ml) Sub-total 124.0mg 124.0mg 124.0mg 124.0mg Carboxylmethylcellulose calcium 5.6 5.6 5.6 5.6 Magnesium stearate 0.4 0.4 0.4 0.4 Total 130.0mg 130.0mg 130.0mg 130.0mg According to the present invention, orally administrable stable pharmaceutical compositions, in which decomposition of the active component is suppressed to maintain its high content ratio even after the lapse of days, can be provided, by having the active components incorporated with an oily substance whose melting point is relatively low.

Claims: A solid pharmaceutical composition for oral use, which comprises (A) an effective amount of a compound of the formula: wherein in the N-containing heterocyclic residue represented by the formula: a represents nitrogen atom; b and c independently represent optionally substituted carbon atoms; which N-containing heterocyclic residue may be substituted, besides Y-R 1 ; R 1 is hydrogen or an optionally substituted hydrocarbon residue; Y is a bond, -O-, -S(O)m-, wherein m denotes 0, 1 or 2, or -N(R 4 )-, where R 4 is hydrogen or an optionally substituted alkyl group; R 3 is tetrazolyl; X is a direct bond between the phenylene group and the phenyl group; n is 1, which has antagonistic action to angiotensin II and (B) an oily substance selected from hydrocarbon, higher fatty acid selected from capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidinic acid, behenic acid, lignoceric acid, cerotic acid and a mixture of them, higher alcohol selected from lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, aralkyl alcohol and a mixture of them, fatty acid ester of polyhydric alcohol, higher alcohol ether of polyhydric alcohol selected from ethers formed by etherification of a polyhydric alcohol with a higher fatty acid alcohol, selected from cetyl alcohol, stearyl alcohol, oleyl alcohol, octyl alcohol and decyl alcohol, polyoxyethylene lauryl alcohol ether, polyoxyethylene cetyl alcohol ether, polyoxyethylene stearyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene octyl alcohol ether, polyoxyethylene decyl alcohol ether, polyoxypropylene polyoxyethylene cetyl alcohol ether, polyoxypropylene polyoxyethylene stearyl alcohol ether, polyoxypropylene polyoxyethylene oleyl alcohol ether, polyoxypropylene polyoxyethylene octyl alcohol ether and polyoxypropylene polyoxyethylene lauryl alcohol ether and a polymeror copolymer of alkylene oxide. A composition according to claim 1, wherein the compound of the formula as defined in claim 1 is a crystalline substance having a melting point of 100 to 200°C. A composition according to claim 1, wherein the melting point of the oily substance ranges from about 20 to 90°C. A composition according to claim 1, wherein the oily substance is a polymer of alkylene oxide. A composition according to claim 1, wherein the amount of the oily substance is less than 0.1 part by weight per 1 part of the composition by weight. A composition according to claim 1, which is a tablet. A method for preparing a pharmaceutical composition for oral use, which comprises (A) an effective amount of a compound of the formula as defined in claim 1, and (B) an oily substance as defined in claim 1, which comprises admixing the compound of the formula as defined in claim 1 with said oily substance and then subjecting the mixture to molding.

Inventors: KIKUTA JUN-ICHI, MAKINO TADASHI, MIZUKAMI YOSHIO, KIKUTA, JUN-ICHI, MAKINO, TADASHI, MIZUKAMI, YOSHIO
Applicants: TAKEDA CHEMICAL INDUSTRIES LTD, TAKEDA CHEMICAL INDUSTRIES, LTD.
Application year: 1992
Main classification: A61K9
IPC codes: A61K31, A61K9