SSR69071 is a potent, orally active, and selective inhibitor of neutrophil elastase, displaying higher affinity for human elastase (Ki = 0.0168 nM) compared to rat (Ki = 3 nM), mouse (Ki = 1.8 nM), and rabbit (Ki = 58 nM) elastases [2]. It reduces myocardial infarct size following ischemia-reperfusion injury [1] and has potential for treating chronic obstructive pulmonary diseases, asthma, emphysema, cystic fibrosis, and various inflammatory diseases.

SSR69071 is a potent inhibitor of human leukocyte elastase (HLE), with an inhibition constant (K i ) of 0.0168±0.0014 nM and an inactivation process constant (k on ) of 0.183±0.013 10 6 /mol sr [2]. It is also a competitive and slow tight-binding inhibitor in vitro, with a K i value of 16.8 pM [3].

SSR69071, when administered intravenously at a dose of 3 mg/kg, significantly diminishes cardiac infarct size if given before ischemia or immediately before reperfusion (−37%, P<0.05), and notably reduces cardiac elastase activity upon administration just prior to reperfusion [1]. In oral treatment scenarios, SSR69071 demonstrates dose-dependent effectiveness in inhibiting human leukocyte elastase (HLE) in bronchoalveolar lavage fluid from mice (ED50=10.5 mg/kg p.o.) and markedly reduces acute lung hemorrhage induced by HLE in mice (ED50=2.8 mg/kg p.o.) [2]. Additionally, SSR69071 effectively prevents carrageenan- and HLE-induced paw edema in rats at specific effective doses (ED30=2.2 mg/kg and ED30=2.7 mg/kg, respectively) following oral administration [2]. This research utilized male New Zealand white rabbits weighing 2-3 kg as the animal model [1], with SSR69071 dissolved in methane sulphonic acid before dilution in 0.9% saline for intravenous (i.v.) administration. The pivotal findings demonstrate that treatment with SSR69071 just prior to reperfusion significantly curtails cardiac elastase activity.