曲马多缓释多囊泡脂质体的制备和释放度影响因素研究

目的 制备包封率高和缓释作用好的PGE修饰的曲马多缓释缓释多囊泡脂质体,并与逆相蒸发法制备的曲马多普通脂质体比较其体外释药性能.方法 用复乳法制备曲马多缓释多囊泡脂质体;非火焰原子吸收分光光度法测定曲马多含量;磷脂酶试剂法测定脂质体中磷脂的浓度;测定包封率和体外释药性.结果 曲马多缓释多囊泡脂质体平均粒径为31.3μm,跨距为1.0;曲马多包封率可高达80%以上;曲马多缓释缓释多囊泡脂质体的体外释药符合一级释药规律,释药时间为72h,比逆相蒸发法制备的曲马多普通脂质体延长16.95（由原来为释药时间37.7h延长8.4倍推出）倍;经差示热分析发现辅助膜稳定剂有明显的膜稳定作用.结论 曲马多缓释多囊泡脂质体包封率高,并具有良好的缓释作用.

Studies on preparation and the factors effecting the releasing rate of Tra- madol PEG-coated multivesicular liposomes

OBJECTIVE To prepare Tramadol PEG-coated mukivesicular liposomes with high encapsulation ef- ficiency and sustained-release character, and compare the release characteristics with conventional liposomes prepared by reverse-phase evaporation method. METHODS Tramadol muhivesicular liposomes were prepared using multiple emulsion method. The concentrations of tramadol and lipids in the liposomes were measured by flameless atomic ab- sorbance spectroscopy （FAAS） and phosphalipid enzyme reagent method, respectively. The encapsulation efficiency, size and release of the tramadol from the liposomes were studied in vitro. RESULTS The mean diameter of tramadol PEG-coated multivesicular liposomes was 31.3 ~m. The release profile in vitro fitted with a first-order equation. encapsulation efficiency of tramadol was more than 80%. The The releasing time of tramadol PEG-coated multivesicular li- posomes was 72h, which was 16.95 that of conventional liposomes. Co-membrane stabilizer had remarkable stabilizing effect on the PEG-coated multivesicular liposomal membrane confirmed by DSC. CONCLUSION The tramadol PEG-coated multivesicular liposomes showes high encapsulation efficiency and sustained release character.