Capillary zone electrophoresis for the determination of amodiaquine and three of its synthetic impurities in pharmaceutical formulations

A simple and robust CZE method was developed for the separation and quantification of the antimalarial compound amodiaquine as well as three of its synthetic impurities at a concentration equal to or lower than 0.5%. For capillary electrophoresis, a fused-silica capillary, a background electrolyte of 100mM sodium phosphate buffer at a pH value of 6.2, a voltage of +20kV, and a detection wavelength of 220nm were used, allowing the determination of the analytes within 20min. The method was validated according to the guideline Q2(R1) of the International Council for Harmonization with respect to linearity, precision, accuracy, limit of detection and limit of quantification, and was successfully applied to evaluate the quality of drug samples collected in the Democratic Republic of the Congo. Quantitative analysis results obtained by the CZE method were compared to those obtained with the contemporary HPLC method described in The International Pharmacopoeia.