Validation of an LC-MS/MS assay for the simultaneous determination of bictegravir, doravirine, and raltegravir in human plasma.

Bictegravir (BIC), an integrase inhibitor, and doravirine (DOR), a non-nucleoside reverse transcriptase inhibitor, were recently approved by the US FDA for HIV treatment and are recommended first line treatment options. Because certain clinical scenarios warrant using them in combination, we developed a fully validated LC-MS/MS method for simultaneous measurement of BIC and DOR, along with a legacy integrase inhibitor, raltegravir (RAL), in human plasma over a clinically relevant 1000-fold range for each analyte. These analytes were extracted from the plasma by protein precipitation with their stable, isotopically labeled internal standards (BIC-d, C-DOR, and RAL-d). Following extraction, samples were analyzed by reverse phase chromatography on a Waters Atlantis T3 C18 (50 ×2.1 mm, 3 µm particle size) column with subsequent detection by electrospray ionization in positive ion mode on an AB Sciex API-5000 triple quadrupole mass spectrometer. The assay was linear (R >0.994) over the selected calibration ranges (20.0-20,000 ng/mL (BIC), 3.00-3000 ng/mL (DOR), and 10.0-10,000 (RAL)). The assay was accurate (inter-assay %Bias ≤ ± 8.5) and precise (inter-assay %CV ≤11.4). This method was validated according to FDA guidance for industry and can be used to assess the pharmacokinetics of two newly approved antiretrovirals, or to support therapeutic drug monitoring for modern antiretroviral therapy.