Simultaneous determination of felbamate and four metabolites in rat cerebrospinal fluid by high-performance liquid chromatography.

An isocratic liquid chromatographic method for direct sample injection has been developed for the quantitation of felbamate and four metabolites in rat cerebrospinal fluid. The method uses 0.050- or 0.025-ml aliquots of cerebrospinal fluid diluted with equal volumes of internal standard. Chromatography is performed on a 150 mm x 4.6 mm I.D. Spherisorb ODS2, 3-microns HPLC column eluted with a phosphate buffer-acetonitrile-methanol (820:120:60, v/v/v) mobile phase and ultraviolet absorbance detection at 210 nm. The linear quantitation ranges are: felbamate and the 2-hydroxy metabolite 0.195-200 micrograms/ml, the propionic acid metabolite 0.195-50.0 micrograms/ml, the p-hydroxy metabolite 0.781 to 50.0 micrograms/ml, and the monocarbamate metabolite 0.098-50.0 micrograms/ml.