[Pharmacokinetics of triptolide in Triptergium wilfordii microemulsion gel].

Objective: To establish a method of determinating the plasma concentration about the triptolide in rat in vivo. And to study the pharmacokinetics of triptolide in transdermal drug delivery system of Triptergium wilfordii microemulsion gel.

Method: The T. wilfordii tablet was regarded as the control, the plasma concentration of triptolide was determined by LC-MS/MS after different route of administration, and the pharmacokinetic parameters were calculated by DAS.

Result: The linear relation of triptolide was excellent within the range of 1-200 ng (r = 0.9967). The minimum detectable concentration were 0.5 microg x L(-1). It was the first-order process. And the pharmacokinetic parameters of triptolide in microemulsion gel was as follow: t(1/2) (2.4 +/- 3.00) h,tmax (6.7 +/- 1.63) h, Cmax (82.9 +/- 17.63) microg x L(-1). To compare the tablets, the microemulsion gel has a longer peak time, and maintain a longer stable plasma concentration. The AUC of tablets and microemulsion gel were (2595.3 +/- 551.15) h x microg x L(-1) and (209.9 +/- 25.34) h x microg x L(-1) and it was a significant differences between the tablet and microemulsion gel (P < 0. 01).

Conclusion: T. wilfordii has rapid absorption in rat in vivo and a stable and persistent plasma concentration after transdermal drug delivery. Therefore, it is rationality after transdermal drug delivery.