Simultaneous determination of dexpanthenol, lidocaine hydrochloride, and mepyramine maleate in combined pharmaceutical gel by capillary electrophoresis

A new capillary electrophoresis method was developed for the simultaneous determination of dexpanthenol (DEX), lidocaine (LID), and mepyramine (MEP) in pharmaceutical preparations. The best results were obtained using 20 mM (pH 3.0) phosphate buffer as the background electrolyte. Separation was obtained using a fused-silica capillary (75 µm internal diameter, 50 cm total length, 41 cm effective length) and a potential of +30 kV at 20 °C. Standards and samples were injected using a pressure injection at 50 mbar for 5s and the analytes were monitored at a detection wavelength of 200 nm. Under optimum conditions, migration times were 2.457 min for MEP, 3.520 min for LID, and7.363 min for DEX. The method was linear over the ranges of 25–200 µg mL ^−1 for DEX, 7.5–60 µg mL ^−1 for MEP, and 7.5–60 µg mL ^−1 for LID. Limit of detection (LOD) values were 0.8 µg mL ^−1 for MEP, 1.8 µg mL ^−1 for LID, and 3.1 µg mL ^−1 for DEX. The developed method is accurate, precise, sensitive, selective, and repeatable.