Capillary zone electrophoresis method for the determination of famotidine and related impurities in pharmaceuticals

A simple and rapid capillary zone electrophoresis (CZE) method with UV detection has been developed for the determination of famotidine and its potential impurities in pharmaceutical formulations. The electrophoretic separation of these compounds was performed using a fused silica capillary and 37.5 mmol L−1 phosphate buffer pH 3.5 as the electrolyte. Under the optimised conditions, six impurities could be resolved from the famotidine peak in less than 7 min. The calibration curves obtained for the seven compounds were linear over the concentration range investigated (from 1.5 to 78.5 μg mL−1). The intra- and inter-day relative standard deviations for the migration times and corrected peak areas were less than 2% and 5%, respectively. The detection limits were found to be 0.09 μg mL−1 for famotidine, and from 0.1 to 0.62 μg mL−1 depending on the impurities. The method has been successfully applied to the determination of famotidine in commercial dosage forms.