No abstract

A novel, simple, and rapid method for the determination of the anesthetics benzocaine and lidocaine in pharmaceutical formulations using capillary electrophoresis with spectrophotometric detection (210 nm) is proposed. In this method, the sample preparation was fast and simple, using only aqueous dilution or extraction with sonication aid. A background electrolyte composed by 10 mmol L ‐1 of monosodium phosphate with pH 2.1 allowed the separation of the anesthetics with good peak resolution in less than 5 min. The limits of quantification were 0.31 and 0.68 mg L−1 for lidocaine and benzocaine, respectively. The intra‐ and inter‐day precisions (RSD%) ranged from 1.1 to 4.8% and the accuracies (as recovery percentage) varied from 84 to 109.4%. The proposed method was successfully applied for analyses of commercial samples of pharmaceutical formulations, such as otologic solution, ointment, and spray solution and lozenges for sore throat.