Compounds of Formula (I): ##STR00001## wherein: R.sup.1 is optionally substituted --C.sub.4-12 alkyl, --C.sub.2-10alkylcycloalkyl, --C.sub.2-6alkylheterocycloalkyl, --C.sub.2-6alkylaryl, optionally substituted 5- or 6-membered aryl or heteroaryl with the proviso that R.sup.2 in not pyridinyl; Z is a bond, CH.sub.2, O, S, SO, SO.sub.2, NR.sup.4, OCR.sup.4R.sup.5 or CR.sup.4R.sup.5O; or Z, R.sup.1 and Q together form an optionally substituted fused tricyclic group; Q is an optionally substituted 5- or 6-membered aryl or heteroaryl ring; X is COR.sup.3; R.sup.2 is CONH.sub.2, CO.sub.2H, CO.sub.2R.sup.7, SO.sub.2R.sup.7 or SO.sub.2NR.sup.8R.sup.9, with the proviso that R.sup.2 is not CO.sub.2R.sup.7, when X is CONH.sub.2; R.sup.3 is OR.sup.6 or NR.sup.8R.sup.9; R.sup.4 and R.sup.5 each independently is H, C.sub.1-6 alkyl or C.sub.1-4 alkylaryl; R.sup.6 is H or C.sub.1-6 alkyl; R.sup.7 is C.sub.1-6 alkyl; and R.sup.8 and R.sup.9 each independently is H or C.sub.1-6 alkyl; or R.sup.8 and R.sup.9 together with the nitrogen atom to which they are attached form a 5- or 6-membered ring which may optionally include 1 or more further heteroatoms selected from O, S and N; or physiologically functional derivatives thereof, with the proviso that formula (I) compounds are not: [3-(acetylamino)-4-cyclohexylphenyl]-butanedioic acid and 3-(acetylamino)-4-cyclohexylphenyl]-butanedioic acid diethyl ether; butanedioic acid [3-methoxy-4-(phenylmethoxy)phenyl]; or butanedioic acid [4-(phenylmethoxy)phenyl]; and with the proviso that when R.sup.1 is C.sub.4-12alkyl, Z is other than a bond, O or CH.sub.2; and physiologically functional derivatives thereof, processes for their preparation, pharmaceutical formulations containing them and their use as inhibitors of matrix metallproteinase enzymes (MMPs) are described.