Liquid chromatographic analysis of phenobarbitone, ethosuximide, phenytoin and carbamazepine on a polystyrene-divinyl benzene column

Abstract

A liquid chromatographic method for the simultaneous assay of four anticonvulsant drugs, phenobarbitone, ethosuximide, phenytoin and carbamazepine on a polystyrene-divinyl benzene column is described. The method was developed by the systematic study of different types of co-polymer materials, type and concentration of organic modifiers, buffer pH and concentration and column temperature. A PLRP-S 100 Å 8 µm column maintained at 60 oC and a mobile phase consisting of acetonitrile-tert-butanol-phosphate buffer (pH 7.6, 0.2 M)-water (25:5:10:60, v/v) were used. The flow rate was 1 ml/min with ultraviolet detection at 220 nm. The method has been validated and used for the analysis of raw materials, finished products and dissolution studies of the drugs.