Frontiers of Chemical Science and Engineering
LC/MS/MS and radioisotope method combined for recognizing the affinity between catalpol and OCT2 transporter
1. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; 2. State Key Laboratory of Drug Delivery Technology and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin 300193, China
More and more herbal medicines are found to be the substrates of drug transporters. In this paper, chromatography/tandem mass spectrometry (LC/MS/MS) combined with radioisotope method was used for the quantification of catalpol, a traditional Chinese medicine, to study the affinity relationship between herbal medicines and transporters. Catalpol uptake experiment was carried out by using several transporters (OAT1, OCT2, OAT3, OATP1B1 and OATP2B1). And samples were precipitated with methanol and quantified with LC/MS/MS. The results show that catalpol has a good affinity with OCT2-transfected S2 cells. After studying drug-drug interaction between catalpol and C-tetraethylammonium (TEA), we found that catalpol is able to facilitate TEA transport mediated by OCT2, suggesting that catalpol could probably be a new promoter of OCT2.