Matrix metalloproteinase-13 (MMP-13) has been implicated as the protease responsible for collagen degradation in cartilage during osteoarthritis (OA). Compounds that inhibit the metalloproteinase at the Zn binding site typically lack specificity among MMP family members. Analogs of the low-micromolar lead MMP-13 inhibitor 4, discovered through high- throughput screening, were synthesized to investigate structure–activity relationships in ...