Stable pharmaceutical formulations for treating internal bowel syndrome containing isoxazole derivatives

A method of treating Irritable Bowel Syndrome in mammals comprises administering to the mammal in a need of treatment an effective dose of a chemically stable pharmaceutical composition comprising:

• a therapeutically effective amount of a material corresponding to a compound formula I;
• ##STR15## wherein:
• R is hydrogen, C.sub.1 -C.sub.3 alkyl, allyl, or ##STR16## R.sup.1 is hydrogen, C.sub.1 -C.sub.3 alkyl, allyl, ##STR17## or --(CH.sub.2).sub.n -x;
• n is to 1 to 5;
• X is an unsubstituted or substituted phenyl, C.sub.1 -C.sub.3 alkoxy, or C.sub.1 -C.sub.3 alkylthio;
• R.sup.2 and R.sup.3 are independently hydrogen, C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 alkoxy, C.sub.1 -C.sub.3 alkylthio, halo, CN, or phenyl;
• or together are --(CH.sub.2).sub.p --;
• p is 3 to 6;
• Y is --CH.sub.2 --, --O--, --SO--.sub.m ;
• m is 0,1, or 2;
• or a pharmaceutically acceptable acid addition salt or solvate thereof;
• an organic carboxylic acid containing 2 or 3 carboxylic acid groups and
• an antioxidant or mixture of antioxidants.

A stabilizer system for a pharmaceutical composition containing a therapeutical amount of a material corresponding to a compound of formula I:

• ##STR18## wherein:
• R is hydrogen, C.sub.1 -C.sub.3 alkyl, allyl, or ##STR19## R.sup.1 is hydrogen, C.sub.1 -C.sub.3 alkyl, allyl, ##STR20## or --(CH.sub.2).sub.n -x;
• n is to 1 to 5;
• X is an unsubstituted or substituted phenyl, C.sub.1 -C.sub.3 alkoxy, or C.sub.1 -C.sub.3 alkylthio;
• R.sup.2 and R.sup.3 are independently hydrogen, C.sub.1 -C.sub.3 alkyl C.sub.1 -C.sub.3 alkoxy, C.sub.1 -C.sub.3 alkylthio, halo, CN, or phenyl;
• or together are --(CH.sub.2).sub.p --;
• p is 3to 6;
• Y is --CH.sub.2 --, --O--, --SO--.sub.m ;
• m is 0,1, or 2;
• or a pharmaceutically acceptable acid addition salt or solvate thereof;
• comprising:
• an organic carboxylic acid containing 2 or 3 carboxylic acid groups;
• and
• an antioxidant or mixture of antioxidants.