Chronopharmacokinetic behaviour of cyproterone acetate in rabbits

Abstract Cyproterone acetate (CPA) is an antiandrogenic compound that shows a rhythmic toxicologic behaviour. The purpose of this study was to determine whether CPA pharmacokinetics in the rabbit were influenced by the administration time of day. Previously synchronised rabbits received a single intravenous dose of 4 mg kg -1 of CPA at two hours after light onset (2 HALO) and 14 hours (14 HALO) after light onset. The drug concentration in plasma samples was determined by high performance liquid chromatography. The mean concentrations in plasma were significantly higher (P c and V ss , differed significantly between 2 and 14 HALO dosage (P