AIM: To study the pharmacokinetics of oleanolic acid liposomes in rats.METHODS: Oleanolic acid liposomes were prepared by ethanol injection-sonication;The pharmaceutical properties including morphology,encapsulation efficiency,particle size,zeta potential were determined.Rats were injected with oleanolic acid lipo-somes and oleanolic acid solution via the tail,respectively.The plasma concentrations of sample in rats were assayed by RP-HPLC.The pharmacokinetic parameters were computered by 3P97 program package.RESULTS: Oleanolic acid liposomes showed almost spherical,the mean diametre was(206.4 ? 4.7) nm.The encapsulation efficiency of oleanolic acid liposomes could be more than 90% based on orthogonal design,and no haemolyticus existed.The plasma concentration-time curves of the oleanolic acid liposomes conformed to a two-compartment model.T1/2? of oleanolic acid liposomes was(33.59 ? 12.53) min,AUC was(240.13 ? 23.62)(?g/mL.min),obviously higher than that of the control preparation.CONCLUSION: The oleanolic acid liposomes with high entrapment efficiency and even size has a good pharmacokinetic parameters by comparison with non-liposomes.