THE PREPARATION AND STABILITY OF LIPOSOMEENCAPSULATED ARA-A

This paper uses several preparation methods, such as thin - film, reverse-- phase evaporation and freeze - thawing methods, and also comparesencapsulation percen-tage of Ara - A in liposome (EN%) of these methods. The best operational conditions ofpreparing liposome-encapsulated Ara-A are explored. A higher EN%,about 50%,which is ten times that reported in foreign literature, is obtained by using improved freeze-thawing method, and this method is easy to operate and repeatable. At the same time, thephysical and chemical stabilities of the liposome - encapsulated Ara - A were observed. Theresult shows that there are no distinct changes in shape, size distribution of liposome, andEN% as well as Ara - A contained in liposome by means of sterilization at 100℃ for 30minutes. Accelerating test at a constant temperature indicates that liposome-entrapped Ara - A has certain chemical stability.