Highly sensitive and specific time-resolved fluoroimmunoassay (TR-FIA) of cyproterone acetate and free cyproterone

We have developed a non-isotopic TR-FIA for Cyproterone acetate and Cyprote rone in plasma. Synthesis of the biotinylated tracers, biotinylated Cyprote rone acetate. and Cyproterone. as well as the preparation of anti-Cyprotero ne acetate and anti-Cyproterone antisera are reported. The specificity of a nti-Cyproterone acetate antiserum resulting from the coupling of link bridg e (link bridge between steroid and BSA). on the 3-position on the steroid s keleton, allowed to carry out the Cyproterone acetate assay directly on ext racted plasma (without chromatography). On the other hand Cyproterone assay s require a purification step, including extraction plus chromatography. be cause the plasma Cyproterone acetate concentrations in Cyproterone acetate- treated women are 200 times higher than for Cyproterone. Theses plasma TR-F IA of Cyproterone acetate and Cyproterone presented the advantage of needin g only small doses of radioactivity for recovery controls, and better prati cability related to the only existing RIA described to date. (C) 2001 Elsev ier Science Ltd. All rights reserved.