Relationship between metabolism and pharmacologic activity of SQ 27,786, an angiotensin converting enzyme inhibitor with potent diuretic activity.
SQ 27,786 is a sulfhydryl-containing angiotensin converting enzyme (ACE) inhibitor, which also possesses potent diuretic activity in dogs after intravenous administration. The absorption, distribution, metabolism and elimination of 35S-labeled SQ 27,786 was studied in dogs to determine if the observed pharmacologic activities were intrinsic to this compound or the result of metabolism to separate ACE-inhibitory and diuretic moieties. The poor pharmacologic activity observed after oral administration was found to be due to poor absorption of the ACE-inhibitory-diuretic compound. The results of this study indicated that SQ 27,786 was excreted largely intact, either as the parent compound, the symmetrical disulfide of the parent compound, or as mixed disulfides of the parent compound with endogenous sulfhydryl compounds (e.g., SQ 27,786-L-cysteine) in a manner similar to captopril. It was concluded that the observed diuretic and ACE inhibitory activities were the result of intact SQ 27,786 and not of metabolites resulting from cleavage of the molecule to separate diuretic and ACE inhibitory moieties.
D000804:Angiotensin II / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism*; D000818:Animals; D001711:Biotransformation; D001794:Blood Pressure / Q000187:drug effects*; D001920:Bradykinin / Q000494:pharmacology; D004231:Diuresis / Q000187:drug effects*; D004232:Diuretics / Q000378:metabolism*; D004285:Dogs; D005260:Female; D008297:Male; D011392:Proline / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology; D011799:Quinazolines / Q000378:metabolism* / Q000493:pharmacokinetics / Q000494:pharmacology; D013462:Sulfur Radioisotopes
D000806:Angiotensin-Converting Enzyme Inhibitors; D004232:Diuretics; D011799:Quinazolines; D013462:Sulfur Radioisotopes; D000804:Angiotensin II; C051776:SQ 27786; D011392:Proline; D001920:Bradykinin