Fast and Simultaneous Analysis of Combined Anti-Diabetic Drugs by Capillary Zone Electrophoresis

A fast capillary zone electrophoretic method with photodiode array detection (CZE-PAD) was established and validated for assays of commonly prescribed anti-diabetic drugs [metformin (MET), glibenclamide (GBM) and gliclazide (GCZ)] in 13 samples including raw material, single and combined tablets. CZE optimization revealed baseline separation of the analytes (Rs > 5.39) in 8 min, in 50 mM borate buffer (pH 9.0), using a capillary with an effective length of 56.0 cm and an inner diameter of 50 µm, a voltage of 20 kV, a temperature of 25°C and a detection wavelength at 210 nm. The method provides excellent linearity, precision (%RSDs < 1.90%), recovery (99.8-101.0%) and low detection and quantitation limits (<4 and 12 µg/mL, respectively). The procedure was fast (seven samples per hour) and cost effective, since no organic solvent, sample pre-treatments or clean-up procedures were required. Importantly, the method was accurate, sensitive and reliable for routine quality control of MET, GBM and GCZ in pharmaceutical products both in single and combined formulations.