Renin inhibitory peptides. Incorporation of polar, hydrophilic end groups into an active renin inhibitory peptide template and their evaluation in a human renin-infused rat model and in conscious sodium-depleted monkeys

We previously reported that Boc-Pro-Phe-N-MeHis-Leuψ[CHOCH 2 ]-Ile-AMP is a potent and specific inhibitor of human renin in vitro. It was shown to resist degradation by selected proteases and a rat liver homogenate. It was shown to inhibit plasma renin activity and to reduce blood pressure in renin-dependent-animal models both by the intravenous and by the oral routes using dilute citric acid as vehicle. We report here a variety of water-solubilizing groups and the resulting structure-activity relationship of these compounds. They all maintain an extremely high level of enzyme inhibitory activity in vitro. Evaluation of these potent renin inhibitors in a human renin infused rat model suggests that some of these compounds exhibit improved pharmacological efficacy in vivo. This observation was further confirmed in the conscious sodium-depleted cynomolgus monkey. Importantly, the oral efficacy was demonstrated in a water vehicle in the absence of citric acid