15-Hydroxycyproterone acetate and cyproterone acetate levels in plasma and urine

15 beta-Hydroxycyproterone acetate (15HOCPA) and cyproterone acetate (CPA) have been quantitated in human plasma and urine by a selective high-performance liquid chromatographic assay. The levels of 15HOCPA in plasma are generally twice those of its precursor CPA, although both compounds appear to have similar clearance rates. Approximately 6% of the dose is excreted into the urine, predominantly (greater than 90%) as the free form of 15HOCPA and CPA.