Study on Pharmacokinetic and Bioavailability of Tamarixetin after Intravenous and Oral Administration to Rats

In this study, a sensitive and reliable HPLC-MS/MS method was established to quantify tamarixetin in rat plasma. This method was then applied to research on the pharmacokinetic and bioavailability of tamarixetin after intravenous and oral administration in vivo. The study was performed on CORTECS C(18) column (4.6 mm × 150 mm, 2.7 μm) using mobile phase composed of methanol-water-formic acid (85 : 15 : 0.1, v/v) at a flow rate of 0.3 mL/min by a tandem mass system with an electrospray ionization (ESI) source in the negative multiple-reaction monitoring (MRM) mode. The calibration curves showed good linearity in the range of 5–4000 ng/mL. The intra- and interday precision of tamarixetin was less than 8.7% and 4.8%, respectively, and accuracy was within ±9.5%. Extraction recovery (91.4–100.0%) and matrix effect (99.4–107.4%) met the guidelines published by regulatory authorities. The oral bioavailability of tamarixetin was 20.3 ± 12.4%.