Antihypertensive activity of alacepril in spontaneously hypertensive rats and deoxycorticosterone acetate-salt hypertensive rats and dogs.

Antihypertensive activity of alacepril (1-[(S)-3-acetylthio-2-methylpropanoyl]-L-prolyl-L-phenylalanine, DU-1219), an orally active angiotensin converting enzyme (ACE) inhibitor, was investigated in hypertensive models with normal or low plasma renin activity (PRA). After single oral administration in spontaneously hypertensive rats (SHR), alacepril (1-30 mg/kg) showed a dose related antihypertensive effect with a gradual onset and long lasting action. The maximum hypotensive effect was about 3 times more potent than that of captopril (3-100 mg/kg) on a weight basis. When comparing the AOC (area over the antihypertensive curve) values, the overall antihypertensive activity of alacepril was 8 times stronger than that of captopril. In deoxycorticosterone acetate-salt (DOCA-salt) hypertensive rats, alacepril (10-100 mg/kg) produced a significant and sustained hypotensive effect. The maximum hypotensive potency and the overall antihypertensive activity of alacepril were remarkably stronger than those of captopril (30, 100 mg/kg). During once daily successive oral administration for 10 days in SHR, alacepril (3-10 mg/kg/d) reduced dose relatedly the daily starting blood pressure. In DOCA-salt hypertensive rats and dogs, alacepril (30 mg/kg/d) produced a significant antihypertensive effect, while captopril (30 mg/kg/d) did not reduce daily starting blood pressure. Therefore, it may be expected that alacepril is a more effective antihypertensive agent than captopril in various hypertensions of different etiology.