A UPLC-MS/MS Method for Simultaneous Quantification of Pairs of Oleanene- and Ursane-type Triterpenoid Saponins and Their Major Metabolites in Mice Plasma and Its Application to a Comparative Pharmacokinetic StudyWenwen Zhao & Zongyang Liu & Weiwei Guo & Kui Luo & Jie Yang & Wei Gao & Xia Wu & Xiaoqing Chen2018PDF