Simultaneous Determination of Major Molnupiravir Metabolite (β-D-N4-hydroxycytidine) and Favipiravir in Human Plasma by HPLC-MS/MS

Introduction. Coronavirus disease 2019 (COVID-19) is an infectious caused by the SARS-CoV-2 virus (severe acute respiratory syndrome-related coronavirus 2). COVID-19 now expected to stay with us for many years as a recurring disease. Molnupiravir and favipiravir are oral antiviral drugs anti-RNA polymerase activity. The Russian Health Ministry has approved molnupiravir treatment of COVID-19. study describes development validation high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) method simultaneous determination β-D-N4-Hydroxycytidine in human blood plasma. could be applied pharmacokinetic favipiravir. Aim. aim this develop validate HPLC-MS/MS bioanalytical Materials methods. plasma HPLC-MS/MS. samples were processed 0.1 % formic acid acetonitrile. Internal standard: promethazine. Mobile phase: 0.01 mol/L Ammonium formate buffer solution (Eluent A), 0.08 aqueous ammonia water/acetonitrile 10 : 90 B). Column: Shim-pack GWS C18, 150 × 4.6 mm, 5 μm. Analytical range: 50.00–10000.00 ng/mL β-D-N4-Hydroxycytidine, 250.00–20000.00 Ionization source: electrospray ionization. Detection conditions: 260.00 m/z → 82.10 m/z, 111.00 127.95 (β-D-N4-Hydroxycytidine); 156.15 65.95 85.00 113.10 (favipiravir); 285.05 198.05 (promethazine). Results discussion. This was validated selectivity, suitability reference standard, matrix effect, calibration curve, accuracy, precision, spike recovery, lower limit quantification, carry-over effect stability. Conclusion. quantitative developed validated. analytical range investigate pharmacokinetics