%0 Journal Article %A Kouichi Minato %A Naoyuki Koizumi %A Seijirou Honma %A Kunio Tsukamoto %A Satoshi Iwamura %T Pharmacokinetics and Biliary Excretion of Osaterone Acetate, a New Steroidal Antiandrogen, in Dogs %D 2002 %R 10.1124/dmd.30.2.167 %J Drug Metabolism and Disposition %P 167-172 %V 30 %N 2 %X The pharmacokinetics and biliary excretion of osaterone acetate (17α-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 of14C-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 17α-acetoxy-6-chloro-21-hydroxy-2-oxa-4,6-pregnadiene-3,20-dione. A significant amount of biliary recycling occurs in dogs. The American Society for Pharmacology and Experimental Therapeutics %U https://dmd.aspetjournals.org/content/dmd/30/2/167.full.pdf