Abstract: A method for the simultaneous determination of prilocaine and lidocaine in vitro percutaneous absorption liquid using gas chromatography-mass spectrometry （GC-MS） has been developed. Ropivacaine served as the internal standard. The sample was alkalified with sodium hydroxide and a single-step liquid-liquid extraction with ethyl acetate. Selected ion monitoring (SIM) method was applied for the detection. Using the method to determine prilocaine and lidocaine in the rapid transdermal study. Prilocaine and lidocaine have good linear relationships in the concentration of 0.016-50.0 mg/L. The recoveries of prilocaine and lidocaine ranged from 85.3% to 109.7%, and the relative standard deviations of intra-day and inter-day were less than 10%. The limits of detection were 3 μg/L for prilocaine and 2 μg/L for lidocaine. This assay was time-saving, alternative and sensitive. It was suitable for the analysis of samples collected from the study on in vitro percutaneous absorption.

Key words: lidocaine, percutaneous absorption , prilocaine, gas chromatography-mass spectrometry (GC-MS)