Development and validation of a high-performance liquid chromatography assay for the quantitative determination of 7-oxo-dehydroepiandrosterone-3beta-sulfate in human plasma

A new, simple, reproducible and reliable high-performance liquid chromatography method with ultraviolet absorbance detection at 240 nm was developed and validated for the determination of 7-oxo-dehydroepiandrosterone-3beta-sulfate in human plasma. The method was based upon solid-phase (C18) extraction of plasma after addition of 17beta-hydroxy-3beta-methoxyandrost-5-en-7-one as internal standard. Using 1 ml of plasma for extraction, the detection limit of the assay was 3 ng/ml. The standard curve was linear over the concentration range 10-1000 ng/ml. Stored at -20 degrees C for about 4 months at various concentrations in plasma, 7-oxo-dehydroepiandrosterone-3beta-sulfate did not reveal any appreciable degradation. Also included herein is a method for the simultaneous detection and determination of 7-oxo-dehydroepiandrosterone and 7-oxo-dehydroepiandrosterone-3beta-acetate in plasma.