Measurement of Danazol and its metabolites by automated direct assay system

An automated direct assay system using high performance liquid chromatography was developed for teh measurement of Danazol ; DA and its two metabolites, △(1)-2-hydroxymethylethisterone (△(1)-2-HME), and 2-hydroxymethylethisterone (2-HME), in biologi-cal fluid (human serum and ascites). Serum concentrations of these compounds were measured up to 24 h following a single oral administration of 200mg of DA to 6 females with en-dometriosis. The maximum serum concentration of DA, △(1)-2-HME and 2-HME was 208, 44 and 58ng/ml, respectively. The serum half-life of DA, △(1)-2-HME and 2-HME was 7.9, 4.3 and 4.4 h, respectively. The mean serum concentration of DA and its two metabolites at the the sampling time (2 h after oral administration of 200mg of DA every 4 weeks) hardly changed in the patients administered 400mg/day of DA over a period of 16 weeks. DA and △(1)-2-HME were detectable in ascites 2, 4 and 8 h after oral administration of 200mg of DA, and 2-HME was detectable in ascites at 4 and 8 h. This system could quantify DA and its matabolites easily and simultaneously, and was considered to be valuable in the studies on the relationship between the pharmaco-kinetics and the clinical effects of DA.