Objective: To prepare epirubicin hydrochloride-loaded long circulating liposome by a method of ammonium sulfate trasmembrane gradients. Methods: A single factor-orthogonal test design was employed to optimize the prescription and process. The entrapment efficiency( EE) of the liposomes was used as the assessment criteria. Results: The optimized prescription and preparing process were as follows: the concentration of soybean phospholipid was 2. 5%,the ratio of drug to lipid( w / w) was 1∶ 12. 5,the ratio of ...