MUSCARINIC RECEPTOR ANTAGONISTS

A muscarinic receptor antagonist of formula (I) or a pharmaceutically acceptable salt thereof, wherein X is N or (a) where R4 is H, halo or C1-C4 alkyl; R1 is H or C1-C4 alkyl; R2 is H or C1-C4 alkyl; Y is a direct link, O or S; m is an integer of from 1 to 4; n is 2 or 3; and R3 is 1- or 2-napthyl or a group of formula (b), (c) or Het where R5 and R6 are each independently H, C1-C4 alkyl, C1-C4 alkoxy, -(CH2)qOH, halo, trifluoromethyl, cyano, -(CH2)qNR7R8, -OCO(C1-C4 alkyl), -SO2NH2 or -CONR9R10; where either R7 and R8 are each independently H or C1-C4 alkyl, or R7 is H and R8 is -SO2(C1-C4 alkyl), -CONR9R10,-CO(C1C4 alkyl) or -SO2NH2; R9 and R10 are each independently H or C1-C4 alkyl; q is 0, 1 or 2; Z and Z1 are each independently O or CH2; p is 1, 2 or 3; and "Het" is pyridyl, pyrazinyl or thienyl. The compounds are particularly useful in the treatment of irritable bowel syndrome.