Simultaneous determination and pharmacokinetics of five bufadienolides in rat plasma after oral administration of Chansu extract by SPE-HPLC method.

A sensitive and rapid solid-phase extraction-high performance liquid chromatography (SPE-HPLC) method has been developed for the determination of five bufadienolides, arenobufagin, teliocinobufagin, cinobufotalin, cinobufagin and resibufogenin in rat plasma and applied to a pharmacokinetic study in rats after oral administration of Chansu extract (Venenum Bufonis). Plasma samples were pretreated with solid-phase extraction using Extract-Clean cartridges, and the extracts were analyzed by a reversed-phase C(18) column on a HPLC system with photodiode array detection (DAD). The calibration curves were linear over the range of 0.10-1.66 microg/ml for arenobufagin, 0.03-1.20 microg/ml for telocinobufagin, 0.01-0.62 microg/ml for cinobufotalin, 0.03-0.70 microg/ml for cinobufagin and 0.02-2.57 microg/ml for resibufogenin, respectively. The limit of quantification was 1.1 ng/ml for arenobufagin, 0.3 ng/ml for telocinobufagin, 9.7 ng/ml for cinobufotalin, 8.8 ng/ml for cinobufagin, 7.7 ng/ml for resibufogenin, respectively. The established method could be easily applied to the determination and pharmacokinetic studies of five bufadienolides in rat plasma after oral administration of Chansu extract.