Exploration of peptidyl hydrazones as water-soluble calpain inhibitors

A series of peptidyl hydrazones was synthesized, and their inhibitory activity against μ-calpain and water-solubility were measured. Among these compounds, N,N-dimethyl glycyl hydrazone 6, which inhibited μ-calpain with IC50 of 0.37 μM, possessed the appropriate water-solubility. Furthermore, hydrazone 6 was found to possess the excellent in vitro metabolic stability.