Depressor effects and pharmacokinetics of single and consecutive doses of delapril in hypertensive patients with normal or impaired renal function

Summary

The antihypertensive effects and pharmacokinetic properties of delapril, an angiotensin-converting enzyme (ACE) inhibitor, were investigated in hypertensive patients with normal renal function (NRF; n=6) and in those with impaired renal function (IRF; n=5). A 15-mg oral dose of delapril was given once on the first and last days, and twice daily on the other days. The measurement of blood pressure and sampling were done at 0, 1, 2, 4, 6, 12, and 24 hours postdose on the first and last days of treatment. Plasma and urinary concentrations of delapril and its metabolites were measured by HPLC. ACE activity was suppressed from 1 hour after the first dose to 24 hours after the last dose of delapril in both the NRF and IRF groups. During the consecutive dosing, significant BP falls were observed from 1 hour postdose of delapril to 24 hours in the NRF group and to 6 hours in the IRF group. Peak plasma concentrations of 5-hydroxydelapril diacid and areas under the plasma concentration-time curve (AUC) of both delapril diacid and 5-hydroxydelapril diacid in the IRF group were significantly higher (p<0.001 or 0.05) than in the NRF group. No significant increase of pharmacokinetic parameters in repeated dosing was observed in both the NRF and IRF groups. Significant positive correlations (p<0.001) were found between the inverse of creatinine clearance and the AUCs of the active diacid metabolites in single and consecutive doses.