title: Enalapril maleate and a lysine analogue (MK-521) in normal volunteers; relationship between plasma drug levels and the renin angiotensin system.
abstract: 1 Two single doses of 10 mg each of the converting enzyme inhibitor enalapril maleate or MK-421 and of its lysine analogue (MK-521) were administered p.o. to twelve male volunteers. 2 The active diacid metabolite of MK-421 and the lysine analogue were determined by radioimmunoassay and MK-421 by the active metabolite method following in vitro hydrolysis. 3 Peak serum levels of MK-421, active metabolite and lysine analogue were reached within 1, 3 to 4, and 6 h respectively. Practically all MK-421 had disappeared from serum within 4 h. 4 A close correlation between percent inhibition of plasma converting enzyme activity and the serum concentration of active metabolite was observed ( r = 0.98, n = 171, P less than 0.001). Similarly, converting enzyme blockade as expressed by the ratio plasma angiotensin II/angiotensin I was closely correlated with serum active metabolite levels (r = 0.93, n = 15, P less than 0.001).
mesh_terms: D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins / Q000097:blood; D002216:Captopril / Q000494:pharmacology; D004151:Dipeptides / Q000097:blood* / Q000494:pharmacology; D004656:Enalapril; D006801:Humans; D017706:Lisinopril; D008297:Male; D012084:Renin-Angiotensin System / Q000187:drug effects*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D004151:Dipeptides; D004656:Enalapril; D002216:Captopril; D017706:Lisinopril