Abstract: To prepare the azithromycin liposome with the granule soybean lecithin,the reversed-evaporation combined with freeze-thawing method was adopted. The entrapment efficiency of azithromycin liposome was determined by reverse dialysis method with HPLC for analyzing its amount. The effects of proportion of components in azithromycin liposome and hydration medium on the entrapment efficiency were studied. The optimum preparation conditions of the azithromycin liposome are:temperature 38 ℃,ratio of azithromycin to lecithin 1:20,ratio of azithromycin to the cholesterol 1:2.5 and 20 ml phosphate buffer solution as hydration medium. Under these conditions,the entrapment efficiency of azithromycin liposome is72.86% . This method is accurate and applicable for the preparation of azithromycin liposome with good stability.

Key words: soybean lecithin, azithromycin liposome, reversed-evaporation combined with freeze-thawing method, stability