Pharmacokinetics and acute effect on the renin-angiotensin system of delapril in patients with chronic renal failure.

The acute effect on the renin-angiotensin system and the pharmacokinetic properties of delapril, a new angiotensin converting enzyme inhibitor and its active diacid metabolites (delapril diacid and 5-hydroxy delapril diacid) arising from delapril in vivo were investigated in 4 hypertensive patients with chronic renal failure (CRF: 4 males, average age 49.5 (37-64) years, mean Ccr 22.2 ml/min/1.73 m2) and 9 patients with essential hypertension (EH: 6 males, 3 females, average age 42.8 (28-61) years, mean Ccr 79.3 ml/min/1.73 m2). In CRF, following a single dose of delapril hydrochloride (30 mg), the biological half lives (t1/2) of delapril diacid and 5-OH-delapril diacid were 4.69, 12.88 hours, the maximum serum concentration (Cmax) and the area under the plasma concentration-time curve ([AUC]24(0)) of delapril and its diacid metabolites were 414, 797 and 435 ng/ml, and 658, 6400 and 5068 ng X h/ml, respectively. In EH, the t1/2 of delapril diacid and 5-OH-delapril diacid were 1.21, 1.40 hours and the Cmax and [AUC]24(0) of delapril and its diacid metabolites were 489, 635 and 229 ng/ml, and 572, 1859 and 948 ng X h/ml, respectively. The [AUC]24(0) in CRF were significantly increased as compared with those in EH. The cumulative urinary excretions were significantly lower in CRF than in EH. The serum angiotensin converting enzyme (ACE) was markedly inhibited in both groups up to 24 hours. The plasma concentration of angiotensin II decreased in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)