Simultaneous CE determination of captopril and indapamide in pharmaceuticals and human plasma

Capillary electrophoresis with UV photo diode-array detection was utilized to adopt a new method for the assay of captopril and indapamide in pharmaceuticals and human plasma. Electrophoretic conditions controlling the analysis were optimized to develop separation, sensitivity and rapidity. The optimum conditions obtained were 100 mM borate at pH 9.0, injection time 10.0 s, voltage 25 kV and column temperature 25 degrees C with detection at 220 nm. Relatively, wide dynamic ranges for captopril (1-100 mg L-1) and indapamide (0.1-40 mg L-1) were obtained. Also, the method recorded acceptable intra- and inter-day accuracy (89.8-97.9%) and precision (0.77-3.50%) in pharmaceutical formulations and human plasma. The sensitivity of the method was developed by the optimization and the preconcentration conducted for human plasma sample using liquid-liquid extraction. The limit of detection gained (0.075 and 0.045 mg L-1 for captopril and indapamide, respectively) reached the level of both drugs possibly found in human plasma. The method is suitable to be applied in pharmaceutical industries for quality control and in clinical laboratories for therapeutic drug monitoring purposes.