Studies directed toward the design of orally active renin inhibitors. 1. Some factors influencing the absorption of small peptides

Article abstract of DOI:10.1021/jm00056a005

A systematic evaluation of structure-absorption relationships using a high throughput intraduodenal rat screening model has led to the delineation of a set of structural parameters that appear to govern bioavailability in a series of peptide-based renin inhibitors. Optimum structures, exemplified by 25 and 41, incorporated a single, solubilizing substituent at the C- or N- terminus combined with a lipophilic P₂-site residue. Both inhibitors gave unprecedented plasma drug levels upon intraduodenal administration to monkeys, and the calculated bioavailability for 41 (14 ± 4%) is the highest reported for any peptidic renin inhibitor.