Determination of Serum Concentration of Triptolide in Patients with Rheumatoid Arthritis and Its Pharmacokinetics Study

Objective To establish an UPLC method for determination of Triptolide in serum and explore its pharmacokinetics in patients with rheumatoid arthritis after oral administration of tripterygium glycosides tablet. Methods Three patients with rheumatoid arthritis were enrolled. Using Estazolam as internal standard, serum was extracted with acetic ether, and determination was performed on column of Waters Acquity C18(2.1 mm×100 mm, 1.7 μm) with mobile phase consisted of acetonitrile-0.1% glacial acetic acid(30∶70) at the flow rate of 0.2 mL/min. The column temperature was 30 ℃, and the detection wavelength was set at 220 nm. The serum concentration of Triptolide was processed by DAS 2.1.1 computer program. Results Triptolide was well-separated from internal standard, and the retention time were about 4.9 min and 8.9 min, respectively. Linear range of Triptolide was 13.13-840.00 ng/mL. RSD of intra-day and inter-day were lower than 15% and the recoveries were 88.25%-99.33%. Pharmacokinetic parameters were as follows:Cmax was(159.97±42.43) ng/mL, Tmax was(1.33±0.58) h, T1/2β was(7.51±2.26) h, and AUC0-12 h was(1131.12±89.20) mg?h/L, respectively. Conclusion Pharmacokinetics of Triptolide conformed to two compartment model. Triptolide can be quickly absorbed, and exists differences among individuals.