Simultaneous determination of lamotrigine, phenobarbitone, carbamazepine and phenytoin in human serum by high-performance liquid chromatography.

A simple reversed-phase high-performance liquid chromatography (HPLC) method was developed for the simultaneous estimation of the antiepileptic drugs (AEDs) lamotrigine (LTG), phenobarbitone (PB), carbamazepine (CBZ) and phenytoin (PHT) in human serum. The procedure involves extraction of the AEDs by mixing 200 microl of serum with 200mul of acetonitrile containing 10 microg/ml of pentobarbitone as internal standard (IS). After centrifugation, 10 microl of the supernatant was injected onto a NOVA PAK C-18 column (250 mm x 4.6mm, 5 microm Hypersil ODS) and eluted with a mobile phase consisting of phosphate buffer (10 mM)-methanol-acetonitrile-acetone in the ratio of 55:22:12:11 (v/v) adjusted to pH 7.0. A UV detector set at 210 nm was employed for detection. The AEDs were well resolved from the human serum constituents and the internal standard. The method can quantify LTG, PB, CBZ, and PHT at concentrations as low as 0.2 microg/ml. The method was quantitatively evaluated in terms of linearity, accuracy, precision, recovery, selectivity, sensitivity, and specificity. The method is simple, convenient, and suitable for the analysis of AEDs from human serum.