title: Using human recombinant UDP-glucuronosyltransferase isoforms and a relative activity factor approach to model total body clearance of laropiprant (MK-0524) in humans.
abstract: A major pathway of elimination of the prostaglandin D2 receptor 1 antagonist laropiprant in humans is by uridine diphosphate-glucuronosyltransferase (UGT)-mediated biotransformation. In this study, liver and kidney relative activity factors were developed for UGT1A1, 1A9 and 2B7 to allow for in vitro-in vivo extrapolation of intrinsic clearance data to whole organ clearance using recombinant human UGT isoforms applying this to laropiprant as a model substrate. The total body metabolic clearance of laropiprant determined using this approach (5.0 L/hr) agreed well with the value determined in vivo following intravenous administration to healthy human volunteers (5.1 L/hr). The results suggest that approximately 36%, 36% and 28% of the hepatic metabolic clearance of laropiprant was mediated by UGT1A1, 1A9 and 2B7, respectively. Likewise, 80% and 20% of the renal metabolic clearance was mediated by UGT1A9 and 2B7, respectively. Furthermore, the data suggested that the contribution of the kidney to the overall total metabolic clearance was minor relative to the liver (≈ 12%).
authors: Pharmacokinetics, Pharmacodynamics, and Drug Metabolism (PPDM), Merck Research Laboratories , West Point, PA (CRG, PL, CM, CW, MS) and Rahway, NJ (DNG) , USA .
authors: Christopher R
authors: CR
authors: Gibson
authors: Ping
authors: P
authors: Lu
authors: Cheri
authors: C
authors: Maciolek
authors: Christen
authors: C
authors: Wudarski
authors: Zoe
authors: Z
authors: Barter
authors: Karen
authors: K
authors: Rowland-Yeo
authors: Mark
authors: M
authors: Stroh
authors: Eseng
authors: E
authors: Lai
authors: Deborah A
authors: DA
authors: Nicoll-Griffith
mesh_terms: D061605:Administration, Intravenous; D000328:Adult; D004958:Estradiol / Q000378:metabolism; D005260:Female; D020719:Glucuronides / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006801:Humans; D007211:Indoles / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D007527:Isoenzymes / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008862:Microsomes, Liver / Q000378:metabolism; D015742:Propofol / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D000090264:UDP-Glucuronosyltransferase 1A9; D055815:Young Adult; D015215:Zidovudine / Q000378:metabolism; D000099148:UGT1A1 Enzyme
chemical_list: D004958:Estradiol; D020719:Glucuronides; D014453:Glucuronosyltransferase; D007211:Indoles; D007527:Isoenzymes; D015742:Propofol; D011994:Recombinant Proteins; D000090264:UDP-Glucuronosyltransferase 1A9; D015215:Zidovudine; D000099148:UGT1A1 Enzyme; C518174:MK-0524; C000715591:UGT1A9 protein, human; C491474:UGT2B7 protein, human