Development and validation of a UPLC-MS/MS method for the simultaneous determination of paritaprevir and ritonavir in rat liver.

Aim: Determination of paritaprevir and ritonavir in rat liver tissue samples. Results: We successfully validated a UPLC-MS/MS method to measure paritaprevir and ritonavir in rat liver using deuterated internal standards (d8-paritapervir and d6-ritonavir). The method is linear from 20 to 20,000 and 5 to 10,000 pg on column for paritaprevir and ritonavir, respectively, and is normalized per milligram tissue. Interday and intraday variability ranged from 0.591 to 5.33% and accuracy ranged from -6.68 to 10.1% for quality control samples. The method was then applied to the measurement of paritaprevir and ritonavir in rat liver tissue samples from a pilot study. Conclusion: The validated method is suitable for measurement of paritaprevir and ritonavir within rat liver tissue samples for PK studies.