Objective: To optimize formulation process of Dioscoreae Rhizoma polysaccharide liposomes and investigate its characterization. Method: The liposomes was prepared by the reverse evaporation-microporous membrane extrusion method.Taking lecithin concentration

ratio of lecithin to cholesterol and ratio of drug to lipid as factors

orthogonal test was adopted to optimize formulation process with entrapment efficiency as index.High-speed centrifugation was developed for determination of entrapment efficiency.The content of Dioscoreae Rhizoma polysaccharide was measured by phenol-sulfuric acid method. Result: Optimum formulation of Dioscoreae Rhizoma polysaccharide liposomes was as following:lecithin concentration of 12 g·L-1

lecithin-cholesterol (6:1)

drug-lipid (1:15).These average values of particle size

polydispersity index and Zeta potential were 121.6 nm

0.136 and -31.8 mV

entrapment efficiency and drug loading were 83.29%and 3.83%

respectively. Conclusion: This optimized process is stable and feasible.Dioscoreae Rhizoma polysaccharide liposomes has round shape

uniform particle size distribution and high entrapment efficiency.