[Determination of evodiamine and rutaecarpine of compound Wuzhuyu cataplasm in plasma by SPE-HPLC: application to its pharmacokinetics].

Objective: To establish a SPE-HPLC method for the determination and pharmacokinetic study of evodiamine and rutacarpine in rat plasma.

Method: A Kromasil C18 column (4.6 mm x 250 mm, 5 microm) was used with acetonitrile-water-tetrahydrofuran-acetic acid (51:48:1:0.1) as a mobile phase and at a flow rate of 1 mL x min(-1), and the UV detection was at 225 nm. The column temperature was 35 degrees C. After the analytes were extracted from the plasma of rats by solid phase extraction (SPE), the content of evodiamine and rutaecarpine was measuared by HPLC method using halcinonide as an internal standard solution.

Result: After transdermal administration to rats, the pharmacokinetic behavior of evodiamine and rutaecarpine belongs to the one-compartment model. The main pharmacokinetic parameters was as follows: K(a) 0.224 h(-1) and 0.220 h(-1), K(e) 0.114 h(-1) and 0.118 h(-1), C(max) 0.211 mg x L(-1) and 0.272 mg x L(-1), T(peak) 6.132 h and 6.102 h, respectively.

Conclusion: The method in this study is simple, rapid and sensitive. It is proved to be suitable for pharmacokinetic study of evodiamine and rutaecarpine.