Simultaneous determination of the tuberculostatic drugs rifampicin, isoniazid, and pyrazinamide by CZE

A simple and cost-effective method by capillary zone electrophoresis (CZE) was developed and validated for the simultaneous determination of the antituberculosis drugs isoniazid (INH), pyrazinamide (PYR), and rifampicin (RIF) in tablets. A 40 mmol L^-1 sodium tetraborate background electrolyte (BGE) solution (pH 9.0) was found to be suitable for separation of all the analytes. An uncoated fused-silica capillary of 64.5 cm length (effective length 56 cm) was used for chromatography separation. All analytes were completely separated within 5 min at an applied voltage of 20 kV (max. 50 µA), and detection was performed at 269.5 nm with an UV detector. The method was validated in terms of linearity, accuracy, precision, and robustness. The linearities of the calibration curves for INH, PYR, and RIF were 40-120 µg/mL (r² = 0.9994), 20-100 µg/mL (r2 = 0.9997), and 40-100 µg/mL (r² = 0.9999), respectively. The proposed method was successfully applied for the simultaneous determination of the tuberculostatic drugs RIF, INH, and PYR in tablets. Thus, the proposed CZE method is a potential alternative to the HPLC methods described by the US Pharmacopoeia for the quality control of tuberculostatic drugs. Colegio de Farmacéuticos de la Provincia de Buenos Aires