title: Pharmacokinetics of propranolol and its metabolites in horses after intravenous or oral administration.
abstract: The pharmacokinetics characteristics of propranolol (PPL) in horses was studied by administering the drug intravenously or orally to the animals. The predominant primary pathway was ring oxidation, and 4-hydroxypropranolol glucuronide (4-OHPG) was the major metabolite in both plasma and urine. Side-chain glucuronidation and oxidation were not significant. A two-compartment model was employed for PPL followed by a one-compartment model for 4-OHPG. After oral administration, one-step absorption and two-step first pass metabolism were employed. The fraction absorbed of PPL was approximately 70% after oral administration, and the bioavailability varied among individual horses from 1 to 79% depending on the first pass metabolism. The biologic half-life (T1/2) of PPL obeys the allometric equation in some animal species including rats and horses, except for human. T 1/2 of PPL in horses was approximately 2 h.
authors.affiliation: Laboratory of Racing Chemistry, 1731-2 Tsuruta, Utsunomiya 320-0851, Japan. sugkarmk@air.linkclub.or.jp
authors.forename: S
authors.initials: S
authors.lastname: Aramaki
authors.forename: M
authors.initials: M
authors.lastname: Mori
authors.forename: M
authors.initials: M
authors.lastname: Nakata
authors.forename: A
authors.initials: A
authors.lastname: Shinohara
authors.forename: T
authors.initials: T
authors.lastname: Koizumi
mesh_terms: D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000465:Algorithms; D000818:Animals; D001711:Biotransformation; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D005470:Fluorometry; D020719:Glucuronides / Q000097:blood / Q000378:metabolism / Q000652:urine; D006736:Horses / Q000378:metabolism*; D007275:Injections, Intravenous; D008297:Male; D008954:Models, Biological; D011433:Propranolol / Q000008:administration & dosage / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D000319:Adrenergic beta-Antagonists; D020719:Glucuronides; D011433:Propranolol