A novel, rapid and simple UPLC-MS/MS method for quantification of favipiravir in human plasma: Application to a bioequivalence study.

A novel, simple and rapid UPLC-MS/MS method was developed and validated for determination of favipiravir (FAV) in human plasma. Lamivudine was used as an internal standard (IS). The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Precipitation with acetonitrile was used in sample preparation as it gives relatively cleaner plasma samples. The prepared samples were chromatographed using an Acquity UPLC® HSS C18 (100 × 2.1 mm, 1.8 μm) column. The mobile phase was composed of ammonium formate and methanol in a gradient mode that was pumped at a flow rate of 0.35 ml/min. The developed method was validated as per the FDA guidelines and linearity was in the range of 0.25-16 μg/ml for FAV. The intra- and inter-day precision and accuracy results were within the acceptable limits. A run time of 4.5 min and a low quantification limit of FAV allowed the application of the developed method for the determination of FAV in a bioequivalence study in healthy human volunteers.