Determination of benperidol and its reduced metabolite in human plasma by high-performance liquid chromatography and electrochemical detection.

An isocratic high-performance liquid chromatographic method with electrochemical detection for the quantification of benperidol and its suggested reduced metabolite TVX Q 5402 in human plasma is described. The method included a two-step solid-phase extraction on reversed-phase and cation-exchange material, followed by separation on a cyanopropyl silica gel column (5 microns; 250 mm x 4.6 mm I.D.). The eluent was 0.15 M acetate buffer (pH 4.7) containing 25% acetonitrile (w/w). Spiperone served as internal standard. The inclusion of the cation-exchange step provided sample purity higher than those achieved with other methods. After extraction of 1 ml of plasma, concentrations as low as 0.5 n…