A potent inhibitor of neutrophil elastase (Ki = 0.0168 nM for the human enzyme); selective for human neutrophil elastase over rat, mouse, and rabbit elastases (Kis = 3, 1.8, 58 nM, respectively); inhibits human neutrophil elastase ex vivo in mouse BAL fluid (ED50 = 10.5 mg/kg, p.o.); reduces acute lung hemorrhage induced by human neutrophil elastase in mice (2.8 mg/kg, p.o.); reduces carrageenan- and human neutrophil elastase-induced paw edema in rats (ED30s = 2.2 and 2.7 mg/kg, respectively); reduces cardiac infarct size in a rabbit model of ischemia-reperfusion injury,