[CAS NO. 81938-43-4]  Zofenopril calcium

In conscious rats, dogs, and monkeys, oral administration of zofenopril (0.03-0.6 mg/kg) induces a dose-dependent inhibition of the pressor response to angiotensin I. It does not antagonize the effects of angiotensin II or other spasmogens. In 2K-1C rats, zofenopril produces a dose-dependent antihypertensive effect of long duration (>17 h). At 6.6 mg/kg, zofenopril lowered blood pressure by as much as 70 mmHg (220 to 150 mmHg). In SHRs, zofenopril has dose-dependent effects, lowering of blood pressure by 21-33 mmHg. At the highest dose used, zofenopril lowers blood pressure for at least 17 h. The effects of repeated administration of 22 mg/kg zofenopril b.i.d. were evaluated in SHRs. Systolic blood pressure (SBP) fell by 47 mmHg (188 to 141 mmHg) by day 14 of the study. The duration of the effect was longer than 12 h as identical SBP values were recorded at either 1 or 12 h after drug administration. Based on urinary excretion after oral and i.v. administration, the oral absorption of zofenopril was estimated to exceed 80% in rats and dogs and 70% in monkeys. The bioavailability of zofenoprilat after an oral dose of zofenopril was 100% in rats, >70% in dogs, and 50% in monkeys. Based on a comparison of AUC values after oral and i.v. administration, the oral absorption of [14C]zofenopril in dogs was 100% and the bioavailability of zofenoprilat was 93%. Following an oral administration of zofenopril, T values for zofenoprilat were between 0.3-0.9 h and T values between 5–7 h for either of the three animal species. In dogs receiving zofenopril by intraarterial, intravenous, intraportal, or oral routes, 95% of the orally administered dose of zofenopril was hydrolyzed during the first pass.