CA1327010C

CA1327010C - Stabilized solid pharmaceutical composition containing antiulcer benzimidazole compound and its production

Info

Publication number: CA1327010C
Application number: CA000529605A
Authority: CA
Inventors: Tadashi Makino; Tetsuro Tabata; Shin-Ichiro Hirai
Original assignee: Takeda Chemical Industries Ltd
Current assignee: Takeda Pharmaceutical Co Ltd
Priority date: 1986-02-13
Filing date: 1987-02-12
Publication date: 1994-02-15
Anticipated expiration: 2011-02-15
Also published as: US5093132A; EP0237200A2; EP0423748A1; EP0423748B1; US5045321A; SG50619A1; HK188195A; DE3750431D1; EP0237200B1; DE3780045D1; EP0446961B1; DE3750431T2; EP0237200A3; EP0446961A3; HK1002021A1; DE3780045T2; DE3751845D1; BG61202B2; DE3751845T2; EP0446961A2

Abstract

Abstract of the Disclosure The pharmaceutical composition of the invention, which comprises a benzimidazole compound of the formula

Description

~ i:
~327~10 Thls inventlon relates to a pharmaceutlcal composltion whlch comprlses 2-[(~-pyrldyl)methylsulphlnyl]benzlmldazole or a derlvatlve thereof (herelnafter sometlmes referred to collectlvely as "benzlmldazole compounds"~, which is useful as an antlulcer agent, as stabillzed by lncorporatlon of a basic lnorganlc magnes-lum and/or calcium compound and its production.
Certaln benzlmldazole compounds are recently under clinlcal study as gastrlc acld secretion inhibltors. They serve as therapeutic agents for dlgestive ulcer. Their principal pharmacological effect consists in gastric acid secretion suppres-sion based on (H+ + K+)-ATPase inhibition and is more potent and durable as compared wlth histamlne H2 receptor antagonlsts such as cimetidine and ranitidine. They also have gastric mucosa protect-ing actlvity. Therefore, they have attracted attention as next-generatlon potent therapeutlc agents for digestlve ulcer.

X

- 2 - ~ ~ ~7~1~

Those benzimidazole compounds which are described in Japanese Unexamine~ Patent laid open Nos. 62275/77, i41783/79, 53406/82, 135881/83, 192880/83 and 181277/84, corresponding to U.S. Patent No~ 4,045,563, U.S. Patent No.
4,255,431, European Patent Publication No. 45,200, U.S. Patent No No. 4,472,409, European Patent Publication No. 5,129 and G.B. Patent Publication No. 2,134,523A, respectively, among others are known to have antiulcer activity.
These compounds, however, are poor in stability. In solid state, they are susceptible to heat, moisture and light and, in aqueous solution or suspension, their stabil-ity decreases with decreasing pH. In dosage forms, i.e.
tablets, powders, fine granules, granules and capsules, said compounds are apt to interact with other components contained in said dosage forms and accordingly are in less stable state as ~ompared with the case where they occur alone. Thus, the content decreases and the color changes significantly in the manufacturing process of dosage form and with the lapse of time. Microcrystalline cellulose, ~: 20 polyvinylpyrrolidone (PVP), carboxymethylcellulose calcium, : :

~ 3 ~ ~ 3~7~1~

polyethylene gl~col 6000 and Pluronic F68 (polyoxyethylene-polyoxypropylene copolymer), for instance are dosage form components adversely affecting the stability of said com-pounds. Furthermore, in the case of coated tablets and coated granules among the above dosage forms, enteric coat-ing bases such as cellulose acetate phthalate, hydroxy-propylmethylcellulose acetate succinate and Eudragit (meth-acrylic acid-acrylic acid copolymer) have poor compatibility with said compounds and cause content decrease and color change. Nevertheless, one or more of these components or ingredients, which, as mentioned above, can produce adverse : effects on the stability of said compounds, are essential in the manufacture of oral preparations and therefore dif-ficulties are inevitably encountered in dosage form manu-facture.
The prior art avoids the above-mentioned stability : problem by using said benzimidazole compounds in a salt : form, say in the form of a lithium~ sodium, potassium, ~: magnesium, calcium or titanium salt [Japanese Unexamined Patent laid open No. 167587/84 IEuropean Patent Publication : No. 1~4,495A)]
However, the above prior art method requires, for the stabilization of the benæimidazole compounds, a step of : converting said compounds to such a salt foxm as mentioned above in advance.

In view of the above, the present inventors made in-_ 4 _ ~ 3,~7 ~ ~ ~

vestigations in anattempt to stabilize pharmaceutical prep-arations containing benzimidazole compounds and, as a re-sult, have completed the present invention.
Thus, this invention relates to S (1) ~ pharmaceutical composition which comprises 2-[(2-pyridyl)methyl5ulfinyl]benzimidazole or a derivative thereof, which has an antiuloer activity, and a basic inorganic magnesium and/or calcium compound, and (2) A method of producing a stabilized pharmaceutical com-position which comprises incorporating a basic inorganic magnesium and/or calcium compound into : a pharmaceutical composition containing 2-[(2-pyridyl-methylsulfinyl3benzimidazole or a derivative thereof, which has an antiulcer activity.
The benzimidazole compounds having an antiulcer activity which are to be used in the practice of the invention are those compounds which are described in the above-cited laid-open patent specifications, for instance and are rep-.: 29 resented by the formula ;
;; R~

(R )m ~J~,JLS--GH .
.. I
R~
wherein Rl is hydrogen, alkyl, halogen, cyano, carboxy, ~ carboalkoxy, carboalkoxyalkyl, carbamoyl, carbamoylalkyl, .j :

" _ 5 1 32 7~ ~

hydroxy, alkoxy, hydroxyalkyl, trifluorome~hyl, acyl,carbamoyloxy, nitro, acyloxy, aryl, aryloxyS alkylthio or alkylsulfinyl, R2 is hydrogen, alkyl, acyl, carboalkoxy, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, alkylcarbonyl-methyl, alkoxycarbonylmethyl or alkylsulfonyl, R3 and R5are the same or different and each is hydrogen, alkyl, alkoxy or alkoxyalkoxy,R4 is hydrogen, alkyl, alkoxy which may optionally be fluorinatedr or alkoxyalkoxy~ and m is an integer of 0 through 4.
The compounds of the formula(I) can be produced by the methods described in the above-cited laid-open patent specifications or modifications thereof.
In the following, brief mention is made of the sub-~tituents in those compounds which have the for-mula ~I) and are already known.
Referring to Rl in the above formula, Cl 7 alkylsmay be mentioned as the alkyl represented by Rl; Cl 4 alkoxys as the aikoxy moiety of the carboalkoxy; Cl 4 alkoxys as the alkoxy moiety of the carboalkoxyalkyl and Cl 4 alkyls as the alkyl moiety; Cl 4 alkyls as the alkyl moiety of the carbamoylalkyl; Cl 5 alkoxys as the alkoxy; Cl_7 alkyls as the alkyl moiety of the hydroxy-alkyl; C1_4alkanoyls as the acyl; phenyl as the aryl; phenyl as the aryl moiety of the aryloxy; Cl 6 alkyls as the alkyl moiety of the alkylthio; and Cl 6 alkyls as the alkyl moiety of the alkylsulfinyl.
Referring to R2, Cl 5 alkyls may be mentioned as ` ` - 6 - ~327~0 the alkyl represented by R2; Cl ~alkanoyls as the acyl;
C1 4 alkoxys as the alkoxy moiety of the carboalkoxy;
C1 4 alkyls as the alkyl moiety of the alkylcarbamoyl;
C1 4 alkyls as each of the alkyl moieties of the dialkyl-carbamoyl; C1 4 alkyls as the alkyl moiety of the alkyl-carbonylmethyl; C1 4 alkoxys as the alkoxy moiety of the alkoxycarbonylmethyl; and C1 4 alkyls as the alkyl moiety of the alkylsulfonyl.
Referrring to R3, R4 and R5, C1 4 alkyls may be men-tioned as the alkyl represented by any of them; C1 8alkoxys as the alkoxy; and Cl ~ alkoxys as each of the alkoxy moieties of the alkoxyalkoxy.
Referring to R4, C1 8 alkoxys may be mentioned as the alkoxy, which may optionally be fluorinated.
Among those compounds of the above orumula (I), (1) the compounds of which R1 is hydrogen, methoxy or trifluoromethyl, R2 is hydrogen, R3 and R5 are the same or different and each is hydrogen or methyl, R4 is fluorinated C2_s alkoxy and m is 1, (2) the compounds of which~Rl i~ hydrogen, fluorine, methoxy or trifluoro methyl, R2 is hydrogen, R3 is hydrogen or methyl, R4 is C3-8 alkoxy, R5 is hydrogen and m is 1, and (3) the compounds of ~7hich Rl is hydrogen, fluorine, methoxy or trifluoromethyl R2 is hydrogen, R3 is Cl_g alkoxy, R4 is Cl_g alkoxy ~7hich may be fluorinated, R5 is hydrogen cns~/
and m is 1.
Detailed mention is now made of the substituents ~ 7 ~ 1327~1~

in such novel compounds.
Referring to R , the lower alkyl represented thereby is preferably Cl 8 lower alkoxy such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentyloxy, hexyl-oxy, heptyloxy or octyloxy and more preerably Cl 4 loweralkoxy.
Referring to R4, Cl 8 lower alkoxys may be mentioned as the lower alkoxy, which may optionally be fluorinated, and preferred examples are as mentioned above for R3. As the fluorinated lower alkoxy, there may be mentioned, for example, 2,2,2-trifluoroethoxy, 2,2,3,3,3-pentafluoro-propoxy, l-(trifluoromethyl)-2,2,2-trifluoroethoxy, 2,2,3,3-tetrafluoropropoxy, 2,2,3,3,4,4,4-heptafluorobutoxy and 2,2,3,3,4,4,5,5-octafluoropentoxy, and fluorinated C
lower alkoxys are preferred.
The position of Rl is position 4 or position 5, preferably position 5~
Some methods of producing the above novel compounds ~hereinafter referred to as "compounds of formula (I')"]
20 are described below.

:~ :
Said compounds can be produced by subjecting a com-pound of the formula : R~

s ~R~ JLs--Cil2~5~3/

: R~

1327~1~

wherein R1-R5 are as defined above, to oxidation.
The oxidizing agent to be used is, for example, meta-chloroperbenzoic acid, peracetic acid, trifluoroper-acetic acid, permaleic acid or the like peracid, sodium bromite or sodium hypochlorite. Examples of the solvent to be used in carrying out the reaction are halogenated hydrocarbons such as chloroform and dichloromethane, ethers such as tetrahydrofuran and dioxane, amides such as di-methylformamide, and water~ These solvents may be used either singly or in admixture. Said oxidizing agent is used preferably in an amount approximately equivalent or slightly excessive relative to the compound (II). Thus, said agent is used in an amount of about 1-3 equivalents, more preferably about l to 1.5 equivalentsO The reaction is carried out at a temperature from about 0C (ice cool-ing) to around the boiling point of the solvent used, generally at a temperature from about 0C (ice cooling) to room temperature, preferably at a temperature of about 0C to 10C. The reaction timQ is generally about 0.1 to 24 hours, preferably about 0.1 to 4 hours.
The desired novel compounds (I') produced by the above reaction can be isolated and purified by conven-tional means such as recrys ~ lization, chromatography and so on.
Said compounds may be converted to pharmacologically acceptable salts by conventional means. As such salts, there may be mentioned hydrochloride, hydrobromide, hydro-iodide, phosphate, nitrate, sulfate, acetate and citrate, 9 ~327~ ~

among others.
The novel compounds (II) can be produced by reacting a starting compound of the formula ~ M O ~SH ( m ) wherein Rl and R2 are as defined above, with a starting compound of the formula R~
R3~R s ( ~r ) xc~lz~
wherein R3-R5 are as defined above and X is a halogen atom.
The halogen atom represented by X is, for example, chlorine, bromine or iodine.
The reacti~n is carried out advantageously ln the presence of a base. As said base, there may be mentioned alkali metal hydrides such as sodium hydride and potassium hydridej alkali metals such as metallic sodium, sodium :
alcoholates such as sodium methoxide and sodium ethoxide, ; alkali metal carbonates such as potàssium carbonate and sodium carbonate, and organic amines such as triethylamine, among others. As the solvent to be used in carrying out the reaction, there may be mentioned, for example, alcohols such as methanol and ethanol, and dimethylformamide. The - 10~ 27~0 base is used generally in an amount slightly excessive relative to the equivalent amount but may also be used in large excess. Thus, it is used in an amount of about 2-10 equivalents, preferably about 2-4 equivalents. The above reaction is carried out generally at a temperature of about 0C to around the boiling point of the solvent used, preferably at about 20C to 80C, for a period of about 0.2-24 hours, preferably about 0.5-2 hours.
Some methods of producing the starting compounds (IV) are described below.
Among the compounds (IV), those compounds wherein R3 and R5 are the same or di~ferent and each is hydrcgen or methyl and R4 is fluorinated C2 5 alkoxy or C3_~ alkoxy can be produced by the ollowing process:
~ 15 ProcesS 1) : N02 R~

CU, ~ R 1' 0~ R ~ -~, : ~ (V) (V~) R' R~
R3~ Rs R3 ~ ~ R5 ( illl) (IX) 327~10 A nitro compound of the formula (V), wherein R3 and R5 are as defined above, is reacted with an alcohol de-rivative of the formula R4 OH (VI) wherein R i5 fluori-nated C2 5 alkyl or C3 8 alkyl, in the presence of a base to give an alkoxy derivative of the formula (VII) wherein R3, R4 and R5 are as defined above. The base to be used in carrying out the reaction includes, among others, al-kali metals such as lithium, sodium and potassium, alka-li metal hydrides such as sodium hydride and potassium hydride, alcoholates such as potassium t-butoxide and sodium propoxide, alkali metal carbonates and hydrogen carbonates such as potassium carbonate, lithium carbonate, sodium carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate, ; 15 and alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The alcohol derivative to be submitted to the reaction includes, among others, propanol t isopropanol, butanol, pentanol, hexanol, 2,2,2-trifluoroethanol, 2,2,3,3,3-pentafluoropropanol, 2,2,3,3-tetrafluoropropanol, 1-(trifluoromethyl)-2,2,2-tri~luoroethanol, 2,2,3,3,4,4,4-heptafluorobutanol and 2,2,3,3,4,4,5,5-octafluoropentanol. While R4 OH itself may be used as a solvent in carrying out the reaction~
ethers such as tetrahydrofuran and dioxane, ketones such as acetone and methyl ethyl ketone, acetonitrile, dimethyl-form~de and hexamethylphosphoric acid triamide, for instance, may also be used as solvents. An appropriate reaction tem-- 12 - ~327~0 perature may be selected within the range of about 0C
(ice cooling) to around the boiling point of the solvent used. The reaction time is about 1-48 hours.
Heating (about 80-120C~ of the thus-obtained com-pound (VII) with acetic anhydride alone or in the presenceof an inorganic acid such as sulfuric acid or perchloric acid gives an 2-acetoxymethylpyridine derivative of the formula (VIII3 wherein R3, R4 and R5 are as defined above. The reaction period is generally about 0.1-10 hours.
The subsequent alkaline hydrolysis of the compound (VIII~ gives a 2-hydroxymethylpyridine derivative of ~le formula (IX). Sodium hydroxide, potassium hydroxide, potassium carbonate and sodium carbonate, for instance, are usable as alkalis, and methanol, ethanol and water, among others, are usable as solvents. The reaction is generally conducted at about 20-60C for about 0.1-2 hours.
The compound tIX) is further halogenated with a chlorinating ag~nt such as thionyl chloride to give a 2-halomethylpyridine d~rivative of the formula (IV) wherein R3, R4 and R5 are as defined above and X is chlorine J bromine or iodine. Usable as solvents are, for example, chloroform, dichloromethane and tetrachloro-ethane. The reaction is generally carried out at about20-80C for about 0.1-2 hours.
The compound (IV) thus produced occurs in the foxm -13_ ~327~ Q

of a salt o~ hydrohalogenic acid corresponding to the halogenating agent used and it is generally preferable to subject said compound to reaction with the compound ~III) immediately.
Among the compounds (V), those compounds wherein R3 i9 Cl 8 lower aLkoxy, R4 is alkoxy which may optionally be fluorinated, and R5 is hydrogen can be produced by the following process:
Process 2) ~CHa o ~ CH3 H

~ ~ R~

~3~R ~ R-A'OH ~CH
(.~ m ~ \~ R~ , ( J~ R~

~: (XV) ~ C~20COC~

: 25 R~

~LY~CRH~2OH

- 14 - 1327~10 Thus, maltol (X) is reacted with a alkyl halide of the formula R3 X in the presence of silver oxide, for instance, to give a compound of the ~ormula (XI). Reaction of (XI) with aqueous ammonia gives a pyridone derivative of khe formula (XII). Direct alkylation of the compound (XII) with an alkyl halide~ or halogenation of (XII) with a halogenating agent such as phosphorus oxychloride follow-ed by reaction of the resultant halo derivative ~XIV) with a lower alcohol of the formula R4 OH in the presence of a base gives a compound of the formula (XIII). The com-pound (XIII) can be converted to the compound (IV~ by direct halogenation with N-bromosuccinimide or chlorine, for instance. The compound IXIII) may also be converted to the compound tIV) by oxidizing the same ~th an oxi-dizing agent such as m-chloroperbenzoic acid, reacting the resultin~ compound ~XV) with acetic anhydride, hydro-lyzing the resulting comppund (XVI) and halogenating the resulting compound (XVII~ with a halogenating agent such as thionyl chloride.
:20 ~ The alkyl halide to be used in the production of the compound (XI) includes, among others, methyl iodide, ethyl iodidef propyl iodide, isopropyl iodide, butyl iodide, pentyl iodide and hexyl iodide, and the alkyl : halide to be used in the production of the compound : 25 ~XIII) further includes, in addition to those mentioned above for use in the production of the compounds (XI~, 2,2,2-trifluoroethyl iodide, 2,2,3,3,3-pentafluoropropyl - 15 ~ ~327~1~

iodide, 2,2,3,3-tetrafluoropropyl iodide, l-(trifluoro-methyl)-2,2,2-trifluoroethyl iodide, 2,2,3,3,4,4,4-hepta-fluorobutyl iodide and 2,2,3,3,4,4,5,5-octafluoropentyl iodide, for instance. Such alkyl iodides are used in an amount o about 1-10 equivalents. Silver oxide, potas-sium carbonate, sodium carbonate or the like is used as a deacidifying agent and dimethylformamide, dimethylacet-amide or the like is used as a solvent. The reaction is generally carried out at room temperature.
The halog~nating agent to ~e used in the production of the compo~nd (XIV) includes, among others, phosphorus oxychloride, phosphorus pentoxide and phosphorus tribro-mide and is used in an amount of 1 equivalent to a large excess. The reaction is carried out at a temperature of about 50-150C. The alcohol to be used for the conver-sion of compound (XIV) to compound (XIII) includes metha-` nol and ethanol and further those alcohol derivaitvesmentioned for use in process 1~ and is used in an amount of 1 equivalent to a large excess, and the base includes thoae sodium alcoholates and potassium alcoholates which cor~espong to the respective alcohols as well as potas-sium t-butoxide, sodium hydride and so forth. An appro-priate reaction temperature may be selected within the range o room temperature to the boiling point o~ the 2S solvent used.
For direct bromination o~ the compound ~XIII) with N-bromosuccinimide, the reaction is preferably carried - 16 - 1327~0 out under light irradiation, and carbon tetrachloride, chloroform, tetrachloroethane or the like is used as a solvent~
The oxidizing agent to be used for the conversion of compound (XIII) to compound (XV) includes, among others, peracids such as meta-chloroperbenzoic acid, peracetic acid, trifluoroperacetic acid and permaleic acid as well as hydrogen peroxide. Usabl~ as solvents for the reaction are halogenated hydrocarbons such as chloroform and di-chloromethane, ethers such as tetrahydrofuran a~d dioxane,amides such as dimethylformamide, acetic acid and water, for instance, and these can be used either singly or in admixture. Said oxidizing agent is pr~ferably used in an amount of about l equivalent to an excess relative to the compound (XIII), more preferably about 1-lO equivalents.
The reaction is carried out at a temperature of about 0C
(ice cooling) to around the boiling point of the solvent used generally for a period of about 0.1-24 hours, prefer-ably or about 0.1-4 hours.
; 20 ~ The conversion of compound (XV) to compound (XVI) is effected by heating lat about 80-120C) the compound ~XV) with ac~tic anhydride alone or in the presence of an in-organic acid such as sulfuric acid ~r perchloric acid and so on~
The reaction period is generally 0.1-10 hours.
The alkali to be used in the alkaline hydrolysis of compound (XVI) to compound (XVII) includes, among others, sodium hydroxide, potassium hydroxide, potassium carbonate - 17 - ~327~10 and sodium carbonate. Methanol, ethanol and water, for instance, may be mentioned as usable solvents. The re-action is generally carried out at a temperature of about 20-60C for a period of about 0.1-2 hours.
For the production of compound (IV) from compound (XVII), a chlorinating agent such as thionyl chloride or an organic sulfonic or organic phosphoric acid chloride such as methanesulfonyl chloride, p-toluenesulfonyl chloride or diphenylphosphoryl chloride is used. When a chlorinating agent such as thionyl chloride is used, it is used in an amount of 1 equivalent to a large excess relative to the compound (XVII) and a solvent such as chloroform, dichloromethane or tetrachloroethane is used, and the reaction is generally carried out at a temperaturP
~15 of about 20-80C for a period of about 0.1-2 hours. When an organic sulfonic or organic phosphoric acid chloride is used~ it is used in an amount of 1 equivalent to a slight~excess relative to the compound (XVII) and the re-action is generally carried out in the presence of a base.
20 ~ As usable bases, there may be mention d organic bases such as trîethylamine and tributylamine and incrganic bases such as ~odium carbonate, potassium carbonate and sodium hydrogen carbonate. The base is used in an amount of 1 equivalent to a slight excess. As usable solvents, there may be mentioned, for example, chloroform, dichloro-methane, carbon tetrachloride and acetonitrile. An appro-priate reaction temperature and an appropriate r~action - 18 - ~327~

can be selected within the ranges of about 0C ~ice cool-ing) to around the boiling point and several minute~ to several hours, respectively.
The above-mentioned novel benzimidazole compounds have excellent gastric antisecretory activity, gastric mucosa-protecting activity and antiulcer activity but have low toxicity, so that they can be used in the treat-ment of digestive ulcers in mammals (e.g. mouse, rat, rabbit, dog, cat, human~
The basic inorganic magnesium or calcium compounds, which are to be used in accordance with the inven-tion, are now described.
Said basic inorganic magnesium compounds include, among others,~m`agnesium ~eYh~3fe~ carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, magnesium metasil-icate aluminate, magnesium silicate aluminate, magnesium silicate, magnesium aluminate, synthetic hydrotalcite ~Mg6A12(OH)16 CO34H2O] and aluminum magnesium hydroxide [2.5MgO A12O3-xH2O~ and said basic inorganic calcium compounds include among others,(precipitated~calcium sarbonate and calcium hydroxide. It is only required of such basic inorganic magnesium and calcium salts to show basicity (p~ of not less than 7) when they are in the form of a 1%
aqueous solution or suspension.
Said basic inorganic magnesium and calcium compounds may be used either singly or in combination of two or more species in an amount which may vary depending on the kinds r-~
- 19 - 1327~
. .
thereof but generally lies within the range of about 0.3-20 parts by weight, preferably about 0.6-7 parts by weight, per part by weight of the benzimidazole compounds.
The composition of the invention may fur-ther contain such additives as vehicles (e.g. lactose, corn starch, light silicic anhydride, microcrystalline cel-lulose, sucrose), binders (e.g. a-form starch, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxy-propylmethylcellulose, polyvinylpyrrolidone~, disinte-grating agents (e.g. carboxymethylcellulose calcium,starch, low substituted hydroxypropylcellulose), surfactants [e.~. Tween*80 (Kao-Atlas), Pluronic*F68 (Asahi Denka; polyoxyethylene-polyoxypropylene copolymer], antioxidants le.g. L-cysteine, sodium sulfite, sodium ascorbate), lubricants (e.g. magnesium stearate, talc), - etc.
The composition of the invention is pre~
pared by homogeneously admixing the above benzimidazole compound, the basic inorganic magnesium ~nd~or calcium compound, and the above additives.
The particle sizes of said benzimidazole compound and said inorganic compound are not especially critical in a condition that they can be homogeneously admixed. For example, preferable perticle size is about less than 100 ~m, more pre~erable one is about less than 20 ~m.
The moisture amount in the composition is preferably aboùt 6 - 60~, more preferably about 20 - 40 as equibrium relative humidity ~E.R.H) * Trade Mark ~1 ~3%7~1 ~

The method of admixlng is not critical as far as the benzi-midazole compound can finally be made in even contact with the basic inorganic magnesium and~or calcium compound. Thus,for example, the additives may be admixed with a mixture of the henzimidazole compound and the basic inorganic magnesium and/or calcium compound as prepared by preliminary admixing, or the basic inorganic magnesium and/or of calcium com~ound may be added to a mixture of the benzimidazole -compound and the additives as prepared by preliminary admixing- ' Said mixture can be made up into dosage forms suited for oral administration, such as tablets, capsules, pow-ders, granules and fine granules, by pe~ se known means.
Tab~ets, granules and fine granules may be coated by a per se known method for the purpose of masking of the taste or providing them with enteric or sustained release property. Usable as coating agents are, for example, hydroxypropylmethylcellulose, ethylcellulose, hydroxy-methylcellulose, hydroxypropylcellulose, polyoxyethylene P/L~f on ~ C
B~ 20 glycol, Tween 80, ~X~}rK~ F68, cellulose acetate phthal-ate, hydroxypropylmethylcellulose phthalate, hydroxymethyl-cellulose acetate succinate, Eudragit*(Rohm, West Germany;
methacrylic acid-acrylic acid copolymer) and pigments such as titanium oxide and ferric oxide.
*Trade Mark -` ~327~10 Tablets~ granules, powders, fine granules and capsules can be produced by a conventional method te.g. the method described in the 10th edition of the Japanese Pharmacopeia under General Rules for Prepara-tions). Thus, for example, tablets are produced by ; adding the basic inorganic magnesium and/or calcium -compound to a mixture of the benzimidazole compound , vehicle and disintegrant, mixing, adding a binder, granulating the mixture, adding a lubricant etc. and 10 tableting the resultant granular composition.
Granules are produced by extrusion in approximately the same manner as in the production of tablets or by coating nonpareils, which contain sucrose and corn starch, with a mixture of benzimidazole compound, 15 a basic inorganic magnesium and/or calcium compound, and additives te.g., sucrose, corn starch, crystalline cellulose, hydroxypropyl-cellulose, methylcellulose, hydroxypropylmethyl-cellulose, polyvinylpyrrolidone) ,,:
` 20 .. ~

,.
v .
':

~%~

Capsules are produced by mere mixing and filling. The dosage forms thus obtained show excellent stability with slight changes in appearance and little decreases in con-tent even after storage for a long period of time.
The pha.rmaceutical composition of the pres-ent invent.ion as obtained in the above manner exhibits excellent gastric antisecretory, gastric mucosa-protecting and antiulcer activities and has low toxicity and there-fore can be used in the treatment of digestive ulcers in mammals (e.g. mouse, rat, rabbit, dog, cat, pig, human).
The pharmaceutical composition of the in-vention can be orally administered for the treatment of digestive ulcers in mammals in admixture with pharma-cologically acceptable carriers, vehicles, diluents andso forth and in the form of capsules, tablets, granules and some other dosage fonms, as mentioned hereinabove.
The dose as the benzimidazole compound lies within the : ~ ran~e of about 0.01 mg to 30 mg/kg/day, preferably about :20 0.~ mg to 3 mg/kg/day.

: The following reference examples and working examples as well as the exparimental examples described laber herein illus-trate the present invention in more detail but are by no 25 mean~ limitative of the present invention.

Reference Example 1 A mixture of 2,3-dimethyl-4-nitropyridine-1-oxide ~327~10 (2.0 g), methyl ethyl ketone ~30 ml), 2,2,3,3,3-penta-fluoropropanol (3.05 ml), anhydrous potassium carbonate (3.29 g) and he~thylphosphori~ acid triamide (2~07 g) was heated at 70-80C with stirring for 4.5 days. Then, the insol-uble matter was filtered off and the filtrate was concen-trated. Water was added to the residue and the mixture was extracted with ethyl acetate. The extract layer was dried over magnesium sulfate, then the solv~nt was distil-led off, and the residue was applied to a silica gel col-umn (50 g). Elution with chloroform-methanol tlO:l) and recrystallization from ethyl acetate-hexane gave 2.4 g of 2,3-dimethyl-4-(2,2,3,3,3-pentafluoropropoxy~pyridine-1-oxide as colorless needles. Melting po~nt 148-149C.
The following compounds (VII) were produced from the corresponding compounds (V) in the same manner as above.
Compounds (VII) R3 R5 R4~elting point (~C) --- .
CH3 H OCH2CF3131.0-131.5 20 Note 1) H H OCH2CH2CH3 Oil Note 2) CH3 H OCH2CH~CH3 Oil Note 1): NMR spectrum (CDC13) ~: 1.01 (3H, t, J =
7 Hz~, 1.81 (2H, m), 2.50 (3H, s), 3.93 (2H, t, J = 7 Hz), 6.50-6.80 (2H, m), 8.10 (lH, d, J ~ 7 Hz) Note 2): NMR spectrum tCDCl3) ~: 1. 07 (3Hr tt J a 7.5 Hz) t 1.65-2.~2 t2H, m), 2.21 (3H, s), 2.52 (3Hr s), 3.99 (2H, t, J ~ 6 Hz~, 6.68 ~lH, d, J =

- 24 - 1327~0 6 Hz), 8.15 (lH, d, J = 6 Hz) Reference Example 2 Concentrated sul~uric acid (2 drops) was added to a solution of 2,3-dimethyl-4-(2,2,3,3,3-pentafluoropropoxy)-pyridine-l-oxide (2.5 g) in acetic anhydride (8 ml) and the mixture was stirred at 110C for 2 hours and then con-centrated. The residue was dissolved in me~hanol (30 ml), 2 N aqueous sodium hydroxide (20 ml) was added, and the mixture was stirred at room temperature for 2 hours. After concentration, water was added to the rasidue and the mix-ture was extracted with ethyl acetate. The extract was dried over magnesium sulfate, the solvent was then distil-led off, and the residue was applied to a silica gel (50 g) column. Elution with chloroform-methanol (10:1) and re-crystallization from isopropyl ether gave 1.6 g of 2-hydrox~methyl-3-methyl-4-(2,2 J 3,3,3-penta~luoropropoxy~-pyridine as a brown oil~
NMR spectrum (CDC13) ~- 2.07 (3H, s), 4.28 tlH, brs), 4.49 (2H, t, J = 12 Hz)~ 4.67 ~2H, sl, 6.69 (lH, d, J = 5 Hz), 8.34 (lH, d, J - 5 Hz) The following compounds (IXj were produced from the corresponding compounds ~VII) in the same manner as men-~; tioned above.
~; Compounds (IX) R3 R5 R4Melting point (C) _ ~
CH3 H OCH2CF393.5-94.0 Note 11 ~ H OCH2CH2CH3 Oil 1327~ ~

No-te 2) CH3 H OCH2CH2CH3 Oil Note 1) NMR spectrum (CDC13) ~: 1.0 (3H, t, J = 7.5 Hz), 1.79 (2H, m), 3.92 (2H, t, J = 6 Hz), 4.51-4.90 (lH, br), 4.68 (2H, s), 6.68 (lH, dd, J = 2 and 6 Hz~, 6.80 (lH, d, J = 2 Hz), 8.28 (lH, d, J = 6 Hz) Note 2) NMR spectrum (CDC13) ~: 1.03 (3H, t, J = 7u5 Hz), 1.82 ~2H, m), 2.02 (3H, s), 3.95 (2H, t, J -6 Hz), 4.62 (2H, s), 5.20 (lH, brd, 5), 6.68 (lH, d, J = 6 Hz), 8.25 (lH, dl J = 6 Hz) Reference Example 3 Thionyl chloride (0.2 ml) was added to a solution of 2-hydroxymethyl 3-methyl-4-(2,2,3,3,3-pentafluoropropoxy)-pyridine (350 mg) in chloroform (10 ml) and the mixture }5 was refluxed for 30 minutes and then concentrated. The residue was dissolved in methanol ~5 ml) and the solution was added to a mixture of 2-mercaptobenzimidazole (200 mg), 28% sodium methoxide solution (1 ml) and methanol (6 ml).
The resultant mixture was refluxed for 30 minutes. The methanol was distilled off, water was added to the residue, and the mixture was extracted with ethyl acetate. ~he extract was washed with dilute sodium hydroxide solution and dried over magnesium sulfate. The solvent was then distilled off, and the residue was applied to a silica gel ~20 g) column. Elution with ethyl acetate-hexane (2:1) and recrystallization from ethyl acetate-hexane gave 370 mg of 2-[[3-methyl-4-(2,2,3,3,3-pentafluoropropoxy)-2-pyridyl~-~L327~0 methylthio]benzimidazoie hemihydrate as colorless plates. Melting point 145-146C.
l~he following compounds (II) were produced by react-ing the compound (III) with the corresponding compound (IV) in the same manner as mentioned above.
Compounds (II) R RR3 R R4 Melting point (C) ) 3 2 2 3 Oil Note) NMR spectrum (CDC13) ~: 0.98 (3H, t, J = 7.5 Hz), 1.54-1.9Z (2H, m), 2.15 (3H, s), 3.80 (2H, t, J = 6 Hz), 4.43 (2H, s), 6.55 (lH, d, J = 6 ; lS Hz), 7.09 (2H, m), 7.50 (2H, m), 3.21 (lH, d, J =
.
6 ~z) Reference Example 4 A solution of m-chloroperbenzoic acid (1.3 g) in ; chloroform (15 ml~ was added dropwise to a solution of `: :
20~ 2-[[3-methyl-4-(2~2~3,3~3-pentafuloropropOxy)-2-pyrldyl]-methylthio]benzimidazole(2.2 g) in chloroform ~20 ml~ with ~ ce cooling over 30 minutes and, then, the re~ction mix-;~ ture was washed with saturated aqueous sodium hydrogen carbonate solution, dried over magnesium sulfate and con-centrated. The concentrata was applied to a silica gel (50 g) column. Elution with ethyl acetate and recrystal-lization from acetone-isopropyl ether gave 1.78 g of 2-[[3 - 27 - ~ ~2 methyl-4-(2~2~3~3,3-pentafluoropropoxy)-2-pyridyl]meth sulfinyl]benzimida~ole [hereinafter sometimes referred to as compound (A)] as pale yellow prisms. Melting point 161-163C (decomposition).
S The following compounds (I) [hereinafter sometimes referred to as compound (B), compound (C) and compound ~D), respectively] were produced in the same manner from the corresponding compounds (II~.
Compounds (I) R1 R2 ~ R4 Melting point (C) (B) H H CH3 H 2 3 178-182 (decomp.) (C) H H H H OCH2CH2CH3 123-125 (decomp.) (D) H H CH3 H OCH2CH2CH3 81-83 Example 1 Of the components given below, the compound (A), magnesium hydroxide, L-cysteine, corn starch and lactose were mixed together, ~hen microcrystalline cellulose, light silicic anhydride and magnesium stearate, each in half the intended amount, were added. After sufficient admixing, the mixture ~as compression-molded on a dry ~granulator (roller compactor; Freund, Japan. The compressad mass was ground in a mortar, the resultant granular mass was passed through a round sieve (16 mesh). The remain-ing portions of microcrystalline cellulose, light silicicanhydride and magnesium stearate were added to the sieved mass and, after admixing, the whole mixture was - 28 - 1327~1~

made up into tablets each weighing 250 mg on a rotaxy tableting machine (Kikusui Seisakusho, Japan).
Composition per tablet:
Compound (A) 50 mg Magnesium hydroxide 30 mg L-Cysteine 20 mg Corn starch 20 mg Lactose 65.2 mg Microcrystalline cellulose 60 mg Light silicic anhydride 1.8 mg Magnesium stearate 3.0 mg Total 250.0 mg Example 2 : Tablets were produced in the same manner as in Ex-ample 1 except that omeprazole INote) was used instead of the compound (A~.
Note: 5-Methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridyl)meth~lsulfinyl]ben~imidazole Example 3 Of the components given below, the compound ~B), precipitated calcium carbonate, corn starch, lactose and hydroxypropylce11ulose were mixed together, water was added, and the mixture was kneaded, then dried in : vacuum at 40C for 16 hours, ground in a mortar and passed 25 through a 16-mesh sieve to give granules. To this wa~ added magnesium stearate and the resultant mixture was made up into tablets each weighing 200 mg on a rotary tableting machine (~ikusui Sei~akusho,Japan).

- 29 - ~327 Composition per tablet:
Compound (B) 30 mg Precipitated calcium carbonate 50 mg Corn starch 40 mg Lactose 73.4 mg Hydroxypropylcellulose 6 mg Magnesium stearate 0.6 mg Water (0.05 ml) Total 200.0 mg Example 4 Tablets ware produced in the same manner as in Ex-ample 3 except that timoprazole (Note) was used instead of the compound (B).
Note: 2-[(2-pyridy])methylsulfinyl]benzimidaZole Example 5 The ingredients given below were mixed well in the porportions given below, water was added, and the mixture ~ was kneaded and granulated in an extruder granulator : (Xikusui Seisa~usho;screen size l.0 mm ~). The ; ~ 20 granules were immediately converted to spherical ~orm in a spheronizer (Fuji Powder~s Marumeriæer, Japan; 1,000 : rpm). The spherical granul0s were then dried under vacuum at 40C fox 16 hours and passed through round sieves to give 12- to 42-mesh granules.
Composition per 200 mg of granules Compound (B) ` 30 mg Heavy magnesium carbonate 20 mg ~27~

Corn starch 80 mg Microcrystalline cellulose 20 mg Carboxymethylcellulose calcium10 mg Hydroxypropylcellulose 10 mg Pluronic F68 4 mg Lactose 26 mg Water (0.1 ml) Total 200 mg Example 6 Granules were produced in the same manner as in Example 5 except that the compound (D~ was used instead of the compound (B).
~xample 7 Enteric granules were produced by coating the gran-~: 15 ules~obtained in Example 3 with an enteric coating com-position specified below using a fluidized bed granulator :(Okawara, Japan) under conditions such that the inlet air temperature was 50C and the granule temperature was 40C.
No. 1 hard capsules were filled with the enteric granules thus:obtained in an amount of:260 mg per capsule using a : oapsule filllng machine (Parke-Da~is, U.5.A.).
: Enteric coating compositlon:
Eudragit:L-30D 138 mg (solids 41.4 mg) : Talc 4.1 mg 2S Polyethylene glycol 6000 12.4 mg :~ Tween 80 2.1 mg Water 276 ~1 - 31 - ~ 3~7~

Composition of enteric granules:
Granules of Example 5 200 mg Enteric coat 60 mg Total 260 mg 5 Composition per capsule:
Enteric granules 260 mg No. 1 hard capsule 76 mg Total 336 mg Example 8 Of the components given below, the compound ~B), magunesium carbonate, socrose, corn starch and crystalline cellulose were thoroughly mixed together to obtain dusting powder.
Nonpareils were put on a centrifugal fluidized coating-granulatar (CF-360 Freund, Japan) and then coated with the : dusting powder as described above, while spraying :;~ hydroxypropylcellulose solution [4% (w/wj], to give ~: spherical granules. The spherical granules were dried in vacuum at 40C for 16 hours and then passed through round : 20 ieves to give 12 to 32-mesh granules.
Composition per 190 m~ of granules:
Nonpareil 75 mg Compound ~B) 15 mg Magnesium carbonate 15 mg Sucrose 29 mg Corn starch 27 mg Crys~alline cellulose 27 mg - 32 - ~327~1~

Hydroxypropylcellulose 2 mg [Hydroxypropoxy group content: 53.4-77.5~]
Water ~0.05 ml) Total 190 mg Example 9 Enteric granules were produced by coating the granules obtained in Example 8 with an enteric coatig composition specified below usig a fluidized bed granulator (Okawara, Japan) under conditions such that inlet air temperature was 50C and the granule temperature was 40C. No. 2 hard capsules were filled with the enteric granules thus obtained in an amount of 240mg per capsule using a capsule filling machine (Parke-Davis, USA).
Enteric coating composition:
Eudragit L~30D 104.7 mg ( olids 31.4 mg) Talc 9.6 mg Polyethylene glycol 6000 3.2 mg Tween 80 1.6 mg Titanium oxide 4.2 mg Water 1220 ~1) Composition of enteric granules:
~ranules of Example 8190 mg . Enterîc coat 50 mg Total 240 mg ~: 25 Composition pe~ capsule:
Enteric granules240 mg : No. 2 hard capsule65 mg Total 305 mg 1327~0 Experimental Example 1 Granules were produced by the method of Example 5 and, after storage at 50C and 75% RH for 1 week, were observed for changes in appearance. Granules were also produced in the same manner except that lactose was used instead of heavy magnesium carbonate or that one of other additives specificed below in Table 1.
Table 1 - Change~ in apperance Additive after 1 week at 50C
and 75% RH

The invention:
Heavy magnesium carbonate Magnesium oxide : 15 Magnesium metasilicate aluminate Synthetic hydrotalcite Aluminum magnesium hydroxide Magnesium silicate Precipitated calcium carbonate : 20 .
:~:

_ 34 _1 3 2 7 ~ ~ O

Magnesium hydroxide Controls:
Sodium carbonate + (to yellow) Potassium carbonate ~ (to yellow) S Sodium hydrogen carbonate~ (to yellow) Magnesium chloride++ (to violet) Magnesium sulfate~+ (to violet) Calcium chloride ++ (to violet) Aluminum silicate + (to violet) No additive ~lactose)++ (to violet) Notes: - : No changes in + : Moderately .
++ : Severely As a result, no substantial changes in appearance were noted for the compositions supplemented with the additives of the invention.
Experimental Example 2 Granules were produced in the same manner as in Example 5 except that the compound (A~, the compound (C), the com-pound ~D~, omeprazole or timoprazole was used instead ofthe compound (B). After storage at 50C and 75% RH for ~ 1 week, they wexe observed for changes in appearance. As a : control to each composition, granules were also produced in the same manner except that lactose was used instead of heavy magnesium carbonate and stored under the same condi-tions.

_ 35 _ 1 ~27~1~

Compound Additive ance after 1 week at 50C and 75~ RH
Compound (A) Invention: ~eavy magnesium carbonate Control: Lactose ++
_ ~
Omeprazole Invention: Heavy magnesium carbonate Control: Lactose ++
. _ . . _ Timoprazole Invention: Heavy ma~nesium carbonate Control: Lactose ++
-- . . . ~
~: Compound (C) Inven.tion: Heavy magnesium carbonate Control: Lactose +~
- _- - _ , Compound tD~ Invention~ Heavy magnesium carbonate -~ Control: Lactose ++

~ Notes: - : No changes ., +~ : Severely As is evldent from the above results, the pharma-ceutical compositions of the invention were all tabla whether the active ingredient was the compound tA), omeprazole, timoprazo1e, the compound (C) or the compound (D).
Experimental Example 3 ~: Pharmaceutical compositions were produced in the same manner as in Examples 3 and 5 except that different basic inorgan.~c Mg or Ca salts were used or that lactose was used as a control, and E~ple 6. After strage at 50C and ` ~ ~327~0 75O RH for 1 week or at 40C for 6 months, the compositions were observed for changes in appearance and for active in-gredient content (residual percentage).

.
.

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- 38 - ~327~

The above results clearly indicate that the composi-tions of the invention show no changes in appear-ance at all and are stable in terms of the active ingredi-ent content.

- ~

.:~

:
.

Claims

1. A solid pharmaceutical composition which comprises:
(a) an antiulcer effective amount of an antiulcer active benzimidazole compound of the formula:

(I) (wherein R1 is hydrogen, alkyl, halogen, cyano, carboxy, carboalkoxy, carboalkoxyalkyl, carbamoyl, carbamoylalkyl, hydroxy, alkoxy, hydroxyalkyl, trifluoromethyl, acyl, carbamoyloxy, nitro, acyloxy, aryl, aryloxy, alkylthio or alkylsulfinyl, R2 is hydrogen, alkyl, acyl, carboalkoxy, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, alkylcarbonylmethyl, alkoxycarbonylmethyl or alkylsulfonyl, R3 and R5 are the same or different and each is hydrogen, alkyl, alkoxy or alkoxyalkoxy, R4 is hydrogen, alkyl, alkoxy which may optionally be fluorinated, ox alkoxyalkoxy, and m is an integer of 0 through 4), (b) a basic inorganic magnesium or calcium compound in an amount sufficient to stabilize the benzimidazole compound (a) in the composition, and (c) a pharmaceutically acceptable carrier.

2. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 2-[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl]methylsulfinyl]benzimidazole.

3. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 2-[[3-methyl-4-(2,2,3,3,3-pentafluoropropoxy)-2-yridyl]methylsulfinyl]benzimidazole.

4. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 2[(4-propoxy-2-pyridyl)methylsulfinyl]benzimidazole.

5. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 2[(3-methyl-4-propoxy-2-pyridyl)methylsulfinyl]benzimidazole.

6. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 5-methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridyl)methylsulfinyl]benzimidazole.

7. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 2-[(2-pyridyl)-methylsulfinyl]benzimidazole.

8. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is magnesium carbonate.

9. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is magnesium hydroxide.

10. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is heavy magnesium carbonate.

11. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is magnesium metasilicate aluminate.

12. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is synthetic hydrotalcite.

13. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is aluminium magnesium hydroxide.

14. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is magnesium silicate.

15. A pharmaceutical composition as claimed in claim 1, wherein the component (b) is precipitated calcium carbonate.

16. A pharmaceutical composition as claimed in claim 1, wherein the benzimidazole compound is 2[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl]methylsulfinyl]benzimidazole and the component (b) is magnesium carbonate.

17. A pharmaceutical composition as claimed in claim 1, which is in particle and enteric-coated.

18. A method of producing a stabilized solid pharmaceutical composition which comprises incorporating a basic inorganic magnesium or calcium compound into a pharmaceutical composition containing an antiulcer effective amount of an antiulcer active benzimidazole compound of the formula:

(I) (wherein R1 is hydrogen, alkyl, halogen, cyano, carboxy, carboalkoxy, carboalkoxyalkyl, carbamoyl, carbamoylalkyl, hydroxy, alkoxy, hydroxyalkyl, trifluoromethyl, acyl, carbamoyloxy, nitro, acyloxy, aryl, aryloxy, alkylthio or alkylsulfinyl, R2 is hydrogen, alkyl, acyl, carboalkoxy, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, alkylcarbonylmethyl, alkoxycarbonylmethyl or alkylsulfonyl, R3 and R5 are the same or different and each is hydrogen, alkyl, alkoxy or alkoxyalkoxy, R4 is hydrogen, alkyl, alkoxy which may optionally be fluorinated, or alkoxyalkoxy, and m is an integer of 0 through 4), and a pharmaceutically acceptable carrier.

19. A solid pharmaceutical composition according to claim 1, which has a moisture content of 6 to 60%.

- 42a -

20. A composition as claimed in claim 19, wherein in the formula (I):
R1 is hydrogen, C1-7alkyl, halogen, cyano, carboxy, carbo-C1-4alkoxy, carbo-C1-4alkoxy-C1-4alkyl, carbamoyl, carbamoyl-C1-4alkyl, hydroxy, C1-5alkoxy, hydroxy-C1-7alkyl, trifluoromethyl, C1-4alkanoyl, carbamoyloxy, nitro, C1-4alkanoyloxy, phenyl, phenoxy, or C1-6alkylthio, C1-6alkylsulfinyl, R2 is hydrogen, C1-5alkyl, C1-4alkanoyl, carbo-C1-4alkoxy, carbamoyl, C1-4alkylcarbamoyl, di(C1-4alkyl)carbamoyl, C1-4alkylcarbonylmethyl, C1-4alkoxycarbonylmethyl, or C1-4alkyl-sulfonyl, R3 and R5 are the same or different and each are hydrogen, C1-4alkyl, C1-8alkoxy or C1-4alkoxy-C1-4alkoxy, R4 is hydrogen, C1-4alkyl, C1-8alkoxy which may be fluorinated or C1-4alkoxy-C1-4alkoxy, and m is an integer of 0 to 4.

21. A composition as claimed in claim 20, wherein [i] the component (b) is a basic inorganic magnesium compound selected from the group consisting of heavy magnesium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, magnesium metasilicate aluminate, magnesium silicate aluminate, magnesium silicate, magnesium aluminate, synthetic hydrotalcite and aluminum magnesium hydroxide; or a basic inorganic calcium compound selected from the group consisting of calcium carbonate and calcium hydroxide and [ii] the amount of the component (b) is such that a 1% aqueous solution or suspension of the composition has a pH of not less than 7.

22. A composition as claimed in claim 21, wherein the amount of the component (b) is 0.3 to 20 parts by weight per part of the component (a).

23. A composition as claimed in claim 22, which is in a tablet, capsule, powder, granule or fine granule form.

24. A composition as claimed in claim 22, which comprises, as the carrier, at least one member selected from the group consisting of a vehicle, a binder, a disintegrating agent, a surfactant, an antioxidant and a lubricant.

25. A composition as claimed in claim 21, 22 or 23, wherein in the formula (I):

R1 is hydrogen, methoxy or trifluoromethyl, R2 is hydrogen, R3 and R5 are the same or different and each are hydrogen or methyl, R4 is fluorinated C2-5alkoxy, and m is 1.

26. A composition as claimed in claim 21, 22 or 23, wherein in the formula (I):
R1 is hydrogen, fluorine, methoxy or trifluoromethyl, R2 is hydrogen, R3 is hydrogen or methyl, R4 is C3-8alkoxy, R5 is hydrogen, and m is 1.

27. A composition as claimed in claim 21, 22 or 23, wherein in the formula (I):
R1 is hydrogen, fluorine, methoxy or trifluoromethyl, R2 is hydrogen, R3 is C1-8alkoxy, R4 is C1-8alkoxy, R5 is hydrogen, and m is 1.

28. A composition as claimed in claim 21, 22 or 23, wherein the component (a) is 2-[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl]methylsulfinyl]benzimidazole, 2-[[3-methyl-4-(2,2,3,3,3-pentafluoropropoxy)-2-pyridyl]methylsulfinyl]benzimidazole, 2-[[4-propoxy-2-pyridyl)methylsulfinyl]benzimidazole, 2-[(3-methyl-4-propoxy-2-pyridyl)methylsulfinyl]benzimidazole, 5-methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridyl)methylsulfinyl]
benzimidazole, or 2-[(2-pyridyl)methylsulfinyl]-benzimidazole.

29. A composition as claimed in claim 1, 19 or 20, in which a compound of formula (I) is excluded, wherein:
(1) R1 is hydrogen, methoxy or trifluoromethyl;
R2 is hydrogen;
R3 and R5 are the same or different and are hydrogen or methyl;
R4 is fluorinated C2-5 alkoxy; and m is 1;
(2) R1 is hydrogen, fluorine, methoxy or trifluoromethyl;
R2 is hydrogen;
R3 is hydrogen or methyl;
R4 is C3-8 alkoxy;
R5 is hydrogen; and m is 1; or (3) R1 is hydrogen, fluorine, methoxy or trifluoromethyl;
R2 is hydrogen;
R3 is C1-8 alkoxy;
R4 is C1-8 alkoxy which may be fluorinated;
R5 is hydrogen; and m is 1.

30. A composition as claimed in claim 21, 22 or 23, in which a compound of formula (I) is excluded, wherein:
(1) R1 is hydrogen, methoxy or trifluoromethyl;
R2 is hydrogen;
R3 and R5 are the same or different and are hydrogen or methyl;

R4 is fluorinated C2-5 alkoxy; and m is 1;
(2) R1 is hydrogen, fluorine, methoxy or trifluoromethyl;
R2 is hydrogen;
R3 is hydrogen or methyl;
R4 is C3-8 alkoxy;
R5 is hydrogen; and m is 1; or (3) R1 is hydrogen, fluorine, methoxy or trifluoromethyl;
R2 is hydrogen;
R3 is C1-8 alkoxy;
R4 is C1-8 alkoxy which may be fluorinated;
R5 is hydrogen; and m is 1.