OBJECTIVETo establish a sensitive HPLC method for determining the concentrations of paeonol in rat plasma and to evaluate its pharmacokinetic characteristics.

METHODThe paeonol from eortex Moutan was distilled by the way of water-vapor. A single i.v. dose of 4 mg x kg(-1) paeonol injection was given to 5 health rats. Paeonol was separated on a Diamonsil -C18 column with methanol-water (60: 40)as mobile phase. The plasma concentrations of paeonol were determined and its pharmacokinetic parameters were calculated and evaluated by using kinetica 4.0.

RESULTThe linear range of the method for paeonol was 0.204-20.4 mg x L(-1) and the determination limit was 0.204 mg x L(-1). The main pharmacokinetic parameters, such as AUC, MRT, C(max), Kel, t(1/2kel), after a single dose of paeonol injection were (111.88 +/- 14.44) mg x L(-1) x min(-1), (23.25 +/- 5.86) min, (8.99 +/- 0.84) mg x L(-1), (0.082 +/- 0.015) min(-1) and (8.73 +/- 1.54) min, respectively.

CONCLUSIONThe HPLC method for determining paeonol concentration in plasma is simple, rapid, sensitive and suitable for pharmacokinetic studies.