Development of HPLC-UV method for rapid and sensitive analysis of topically applied tetracaine: its comparison with a CZE method

Topically applied tetracaine is a local anaesthetic. A novel HPLC method for the rapid and sensitive analysis of tetracaine was developed and compared with a short end direction capillary zone electrophoresis (CZE) method. The method was developed and validated for the separation and quantification of tetracaine in skin samples removed by tape-stripping'. Tetracaine was extracted from tape with 100% methanol, which was then diluted to 50% with water for injection. Tetracaine and the internal standard, procaine, were separated on a reversed-phase Luna PFP(2), 3 mu m, 150x4.6mm column at ambient temperature using isocratic elution with KH2PO4 buffer (pH2.5) and methanol (35:65, v/v). The flow rate was 1mL/min, with detection at 312nm. The limit of quantification for tetracaine was 0.03 mu g/mL. Calibration lines were linear with r2 values >0.99. The within- and between-assay imprecision and the percentage of inaccuracy for the QC samples including lower and upper limits of quantitation were <6 and <10%. The absolute mean recovery of tetracaine was >92%. Compared with CZE, the mean percentage error and the absolute mean percentage error were 0.62 and 6.29, respectively. The two methods were compared in a number of pharmacokinetic studies. Copyright (c) 2014 John Wiley & Sons, Ltd.