Simultaneous Determination of Bromhexine and Amoxicillin in Pharmaceutical Formulations by Capillary Electrophoresis

A simple and time-efficient method, based on capillary zone electrophoresis, was developed for the simultaneous determination of bromhexine (BMX) and amoxicillin (AMX) in pharmaceutical formulations. The optimized electrophoretic conditions comprise 50 mM sodium phosphate plus 50 mM citric acid as running buffer (pH 3.0), cartridge temperature 25 degrees C, hydrodynamic injection (5 s. at 0.5 psi), 30 kV separation voltage, and UV detection at 214 nm. The analytes were separated in less than 5 min. Formulation samples were processed by successive treatment with methanol, hydrochloric acid, filtering and dilution in the running buffer. Loperamide was used as internal standard for quantitation. A linear detection range of 10-85 mu g/mL for BMX (R-2 = 0.997) and 250-2010 mu g/mL for AMX (R-2 = 0.995) was observed, with LOD for BMX as low as 2 mu g/mL. The developed method enabled high analyte recoveries (99-104%) and excellent run-to-run reproducibility. Moreover, it was successfully employed for the determination of BMX and AMX in several pharmaceutical formulations, demonstrating its applicability to the routine quality control.