Compounds of formula (I): wherein R1 represents optionally substituted C4-12 alkyl, optionally substituted C2-6alkylaryl, or optionally substituted 5- or 6-membered aryl or heteroaryl; Z represents a bond, CH2, O, S, SO, SO2, NR4, OCR4R5, CR4R5O, or Z, R1 and Q together form an optionally substituted fused tricyclic group; Q represents an optionally substituted 5- or 6-membered aryl or heteroaryl ring; X represents COR3 or N(OR8)COR9; R2 represents SO2R10 or SO2NR10R11; R3 represents OR6, NR6R7 or NR6OH; R4 and R5 each independently represents H, C1-6 alkyl or C1-4 alkylaryl; R6 and R7 each independently represents H, C1-6 alkyl, or C1-6 alkyl substituted with one or more heteroaryl groups, or R6 and R7 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; R8 and R9 each independently represents H or C1-6 alkyl; R10 and R11 each independently represents H or C1-6 alkyl; and and physiologically functional derivatives thereof, with the exception of N-(ethoxycarbonyl)-N-[4-(1H-tetrazol-1-yl)phenyl]glycine, processes for their preparation, pharmaceutical formulations containing them and their use as inhibitors of matrix metalloproteinase enzymes (MMPs) are described.