Evaluation of a rapid method for the simultaneous quantification of ribavirin, sofosbuvir and its metabolite in rat plasma by UPLC-MS/MS

A rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of ribavirin, sofosbuvir and its metabolite GS-331007 in rat plasma was established. The analytes and the internal standard (midazolam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1 mm x 50 mm, 1.7 mu m) using gradient elution with a mobile phase of acetonitrile and 0.1% formic acid in water at a flow rate of 0.4 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 245.1 -> 113.1 for ribavirin, m/z 530.3 -> 243.1 for sofosbuvir, m/z 261.5 -> 113.1 for GS-331007 and m/z 326.2 -> 291.1 for midazolam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 5-1000 ng/mL for ribavirin, 10-2000 ng/mL for sofosbuvir and 10-2000 ng/mL for GS-331007. Total time for each chromatograph was 3.0 min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD) <10.0% and the accuracy values ranged from -10.6% to 11.6%. The method was successfully applied to a pharmacokinetic study of ribavirin, sofosbuvir and GS-331007 in rats. (C) 2015 Elsevier B.V. All rights reserved.