Remacemide hydrochloride, a novel anticonvulsant agent, and its major active metabolite, desglycinylremacemide, were measured simultaneously in brain tissue by high-performance liquid chromatography with UV detection. Intra- and inter-assay variations for remacemide (1, 5, 10 microg/ml) were 5.1, 10.5 and 3.1% and 3.1, 4.0 and 1.3%, respectively. Intra- and inter-assay variations for desglycinylremacemide (1, 5, 10 microg/ml) were 4.2, 3.8 and 8.4% and 7.9, 8.8 and 3.1%, respectively. Limits of detection and quantification for both analytes were 4 and 31 ng/ml, respectively, with recovery consistently > or =85%. This reliable assay has applications in the pre-clinical neuropharmacokinetic and neuropharmacodynamic investigation of remacemide hydrochloride.