Quantitative Assessment of Lamivudine, Lopinavir and Ritonavir in Human Plasma Using a Validated LC–MS/MS Method

The simultaneous determination of antiretroviral drugs with diverse physicochemical properties in biological matrices is analytically challenging. Lamivudine is a hydrophilic nucleoside reverse transcriptase inhibitor, whereas Lopinavir and Ritonavir are relatively lipophilic protease inhibitors. The present study was designed to develop and validate a simple and sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method to quantify Lamivudine, Lopinavir and Ritonavir in human plasma using Tenofovir as internal standard. The method exhibited highly sensitive range for 6.129-3000 ng/mL for Lamivudine, 50.433-20173.143 ng/mL for Lopinavir and 50.358-20143.302 for Ritonavir. The analytes were extracted from plasma using protein precipitation technique. Lamivudine, Lopinavir and Ritonavir were separated using Thermo Hypersil C18 column with a gradient mobile phase consisting 0.1% Formic acid in Water: Acetonitrile (10:90) v/v at 0.5 mL/min with 4 min run time. The validated parameters were within the acceptance criteria as per the regulatory guidelines and the validated calibration curve ranges for all the analytes have correlation coefficient (r2) value  0.99 with above 90% recovery. The developed method was found to be suitable for pharmacokinetic and therapeutic drug monitoring studies involving antiretroviral drugs.