Determination of progabide and its acid metabolite in biological fluids by high-performance liquid chromatography on silica column with ultraviolet detection.

A high-performance liquid chromatographic method has been developed for the determination of progabide and its main acid metabolite in blood, serum and plasma. The assay involved a single and rapid extraction of drug and metabolite into toluene from the biological matrix buffered at pH 4.8, evaporation of the organic phase, and chromatography of the extracts on a silica column with UV detection. SL 81 0142 was used as internal standard. The method was specific for unchanged drug and metabolite and had a sensitivity of ca. 50 ng/ml of biological fluid for both the compounds. The method was successfully applied to the analysis of progabide and its metabolite in biological fluids of patients administered orally with progabide for clinical pharmacokinetic studies and drug monitoring.