Determination of puerarin in pharmaceutical and biological samples by capillary zone electrophoresis with UV detection

A rapid and efficient capillary zone electrophoresis (CZE) method with ultraviolet detection has been successfully developed for the determination of puerarin in Xinkeshu capsules and biological samples. The optimal CZE conditions were determined to be 70 mM H3BO3–Na2B4O7, pH 9.2, injection time 5 s, applied voltage 25 kV, working temperature 25 °C and detection wavelength 254 nm. Under these conditions, a linear range from 17.3 to 138 μg/mL with the correlation coefficient of 0.9998 and limit of detection of 34.6 ng/mL (S/N = 3) for puerarin were obtained. The relative standard deviation of the migration time and peak area of puerarin were 0.23–0.91, 0.43–1.62, 0.10–0.64 and 0.64–1.32% for intra-day and inter-day analyses, respectively. Satisfactory results were obtained for recovery and repeatability. The proposed method was successfully applied to analyze the puerarin content in Xinkeshu capsules and some biological samples with good results. It is suitable for applications in pharmaceutical industries for quality control and in clinical laboratories for therapeutic drug monitoring purposes.