Simultaneous quantification of lidocaine and prilocaine in human plasma by LC-MS/MS and its application in a human pharmacokinetic study

Objective: The aim of the work was to develop and validate a simple, sensitive and selective Liquid chromatography with Mass spectroscopic method for simultaneous quantification of lidocaine and prilocaine in human plasma. Design and methods: Analytes and the internal standards from human plasma were extracted by using solid- phase extraction technique using Waters Oasis (R) HLB 1 cc (30 mg) cartridges. The reconstituted samples were chromatographed on Phenomenex Kinetex EVO 4.6*100 mm 2.6 mu 100A column by using a mixture of acetonitrile and 5 mM ammonium acetate buffer (80:20, v/v) as the mobile phase at a flow rate of 0.6 mL/min. Results: The method was validated over the concentration range of 0.10-201.80 ng/mL for lidocaine and 0.10-201.66 ng/mL for prilocaine. The calibration curve obtained was linear. Conclusion: Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 3.0 min for each sample, make it possible to analyze more than 350 human plasma samples per day. The proposed method was found applicable for pharmacokinetic studies.