Development and Validation of a Sensitive UPLC-Q-TOF-MS/MS for the Measurement of Nine Components in Rat Plasma and Tissues and its Application to Pharmacokinetics and Tissue Distribution Studies with Xuanfei Baidu Granules

Background: Xuanfei Baidu granules (XFBD granules) are based on the prescription of Xuanfei Baidu, which showed promise as a first-line treatment against Corona Virus Disease 2019 (COVID-19) in Wuhan, Hubei. On March 2, 2021, XFBD granules were marketed as a novel drug for epidemic diseases. However, there is little information about the pharmacokinetics and tissue distribution of the main constituents in XFBD granules. Methods: A sensitive analytical method was developed for detecting the marker components of XFBD granules by ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS), and for studying its pharmacokinetics and tissue distribution by UPLC-QDa. Results: Following an oral administration of a single granule in experimental rats at a dose of 14 g/kg for pharmacokinetic and tissue distribution studies, 42 compounds and nine analytes were identified in XFBD granules. Nine compounds were detected in the lungs and the liver of the rats. Six compounds were detected in the kidneys. Five compounds were detected in the spleen and three were detected in the heart. As it went undetected in the brain, XFBD granules are considered unable to cross the blood-brain barrier. Conclusion: A sensitive UPLC-Q-TOF-MS/MS method was established and validated for the quantification of nine components in rat plasma and tissue samples. This method was successfully applied to study the pharmacokinetics and tissue distribution profiles of XFBD granules after their oral administration.