A selective cathepsin B inhibitor (Kis = 0.0087, 75, and 233 μM for rat cathepsin B, H, and L, respectively); inhibits degradation of DQ-collagen IV and DQ-collagen I in 4T1.2 breast cancer cells; reduces the number of lung and bone metastasis in a 4T1.2 mouse xenograft model at 50 mg/kg; reduces mercury-induced increases in expression of TNF-α, IL-1β, and the inflammasome component NRLP3 and decreases the severity of mercury-induced skin induration in mice at 0.1 and 0.2 mg/kg; reduces ischemia-induced hippocampal neuron cell death in monkeys