The pharmacokinetics and metabolism of DuP 532, a non-peptide angiotensin II receptor antagonist, in rats and dogs

✍ Scribed by Y. N. Wong; K. A. Holm; D. L. Burcham; S.-M. Huang; C. Y. Quon

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 481 KB
• Volume: 15
• Category: Article
• ISSN: 0142-2782
• DOI: 10.1002/bdd.2510150105

✦ Synopsis

DuP 532, 2-propy1-4-pentafluoroethyl-l-[ [2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methylJ imidazole-5-carboxylic acid, is an orally active, non-peptide angiotensin I1 (AII) receptor antagonist. DuP 532 is more potent and longer acting than losartan, another A11 receptor antagonist currently undergoing phase I11 clinical trials. The pharmacokinetics and the effect of the salt form on the bioavailability of DuP 532 were determined in rats and dogs. In rats, the absolute oral bioavailability and half-life averaged 8.0% and 3.5 h, respectively, after the sodium bicarbonate solution and 7.6% and 3 -6 h, respectively, after the methyl cellulose suspension. In dogs, the absolute oral bioavailability averaged 13.4% after the sodium bicarbonate solution and 1 1 -9% after hard gelatin capsules containing the neat powder. The data demonstrated that there were no differences in bioavailability between the free acid and the sodium salt of DuP 532 after oral administration to rats and dogs.

The in vitro metabolism of I4C-DuP 532 was evaluated with rat, dog, and human liver microsomes. HPLC analyses with UV and radiochemical flow detection showed that recovery of DuP 532 was greater than 99%, suggesting that there was little if any metabolism by liver microsomal enzymes. Therefore, the low oral bioavailability in rats was probably due to poor absorption of DuP 532 from the GI tract rather than extensive metabolism.