Objective:To establish a method for determining entrapment efficiency（EE） of chlorin e6 liposomes

and to investigate effect of different factors on it.Method:Sephadex G50 and Sephadex G75 column filtration methods were used to separate free drug and liposomes

in order to optimize a method to determine EE of chlorin e6 liposomes;With EE as index

influence of phospholipid concentration

cholesterol amount

hydration medium

temperature and time on preparation of chlorin e6 liposomes were investigated by single factor test.Result:EE of chlorin e6 liposomes was determined by Sephadex G50 column chromatography

its recovery for free drug was up to 100.6%

RSD of repeatability test was less than 0.02;Ratio of phospholipid-cholesterol

drug-lipid ratio and hydration medium had great effect on EE.Conclusion:Sephadex G50 column filtration method was a good way to determine EE of chlorin e6 liposomes easily and quickly

established method was stable and feasible.