Pharmacology of a phosphorus-containing novel angiotensin converting enzyme inhibitor, SQ 29 852 in anesthetized dogs.

The effects of (S)-1[6-amino-2[[hydrozy(4- phenylbutyl)phosphinyl]oxy]-1-oxohexyl]-L-proline (SQ 29 852), a phosphorus-containing novel angiotensin converting enzyme inhibitor (ACEI), which is synthesized aiming an ACEI with long-lasting activity and with few side effects, were studied using anesthetized dogs. SQ 29 852 was equipotent with captopril to modify blood pressure response of the animals to angiotensin I (Ang I) and bradykinin (Bdk). An intravenous infusion of SQ 29 852 at 0.1 mg/kg/min for 30 min caused a remarkable hypotension without reflex tachycardia in open-chest dogs. In these animals cardiac contractility (dP/dtmax of left ventricular pressure) appeared to be reduced by SQ 29 852 without any changes in right atrial pressure (RAP), left ventricular end-diastolic pressure (LVEDP) and aortic blood flow (AoF, cardiac output). In sodium-restricted dogs, the hypotension and renal vasodilation by SQ 29 852 (at 0.01, 0.1, and 1 mg/kg, i.v.) were slightly pronounced compared with animals fed with normal diet. It is demonstrated from these results that SQ 29 852 has comparable potency with captopril to inhibit angiotensin converting enzyme (ACE) activity and as common a pharmacological profile as ACEI. SQ 29 852 may be a favorable antihypertensive agent, if its long-lasting activity and few side effects are confirmed.