Objective: To establish a method to determine the entrapment efficiency of oleanolic acid liposomes. Method: Oleanolic acid liposomes were prepared by film dispersion method. Entrapment efficiency was determined after the separation of the unentrapped drug by glucan gel column chromatography. Distilled water was used to elute liposomes

0.5% SLS was used to elute unentrapped drug. The content of oleanolic acid was deternined by HPLC. Result: The linear range of oleanolic acid was 0.302-30.2 mg·L-1(r=0.999 9).The average recovery was 99.92% (RSD 1.59%). The recovery of glucan gel column chromatography was 100.22% (RSD 1.23%)

and the recovery of oleanolic acid was 99.04% (RSD 0.99%). The average entrapment efficiency of oleanolic acid liposomes was 83.4%. Conclusion: This method is accurate

credible and it can be used to determine the entrapment efficiency of oleanolic acid liposomes.