title: Pharmacokinetics and biliary excretion of osaterone acetate, a new steroidal antiandrogen, in dogs.
abstract: The pharmacokinetics and biliary excretion of osaterone acetate (17alpha-acetoxy-6-chloro-2-oxa-4,6-pregnadiene-3,20-dione; OA), a new steroidal antiandrogen, were investigated in intact dogs and biliary fistula dogs after bolus intravenous administration of (14)C-labeled drug. In intact dogs, OA exhibited a biexponential disposition with a very long half-life of 197.9 +/- 109.9 h. OA accounted for almost all the plasma radioactivity. The major route of excretion was in feces via the bile. One-third of the radioactivity in the bile was due to OA. The major biliary metabolite was identified as a glucuronide of 17alpha-acetoxy-6-chloro-21-hydroxy-2-oxa-4,6-pregnadiene-3,20-dione. A significant amount of biliary recycling occurs in dogs.
authors.affiliation: Pharmacokinetics Research Department, Teikoku Hormone Manufacturing Company, Takatsu-ku, Kawasaki-shi, Kanagawa, Japan. minato-k@kw.teikoku-hormone.co.jp
authors.forename: Kouichi
authors.initials: K
authors.lastname: Minato
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Koizumi
authors.forename: Seijirou
authors.initials: S
authors.lastname: Honma
authors.forename: Kunio
authors.initials: K
authors.lastname: Tsukamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwamura
mesh_terms: D000726:Androgen Antagonists / Q000737:chemistry / Q000493:pharmacokinetics*; D000818:Animals; D001646:Bile / Q000378:metabolism*; D002715:Chlormadinone Acetate / Q000031:analogs & derivatives / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D002855:Chromatography, Thin Layer; D004285:Dogs; D005260:Female; D008297:Male; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D000726:Androgen Antagonists; D002715:Chlormadinone Acetate; C069297:osaterone acetate