Optimised determination of clobazam in human plasma with extraction and high-performance liquid chromatography analysis

The analysis of clobazam by high-performance liquid chromatography and UV d etection is described herein. After adding an internal standard, 600 mul of plasma were extracted under basic conditions onto disposable cartridges pa cked with celite. The organic extract was then evaporated to dryness and th e residue reconstituted in 200 mul of mobile phase. A 20 mul aliquot was in jected into chromatograph. The HPLC system was equipped with an Ultrasphere C8 analytical column coupled with an UV detector set at 235 nm. The mobile phase was an acetate buffer 20 mM, pH 5.5, containing acetonitrile and tri ethylamine 70:30:0.01 (v/v); the flow-rate was 1.8 ml/min. Using this metho d, clobazam can be detected with a sensitivity limit of 6 ng/ml and the RSD % intra- and inter-assay were lower than 5%. For its ruggedness and reliabi lity, the proposed method is particularly suitable for therapeutic drug mon itoring in epilepsy. (C) 2001 Elsevier Science B.V. All rights reserved.