曲马多PEG2000修饰多囊泡脂质体的制备及形态学观察

 目的 制备包封率高和缓释作用好的曲马多PEG2000修饰多囊泡脂质体，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PEG2000修饰多囊泡脂质体；L₉(34 )正交实验设计进行处方筛选和优化，测定包封率和粒径，以pH 6.8 PBS为释放介质考察体外释放特性。结果 未修饰和PEG2000修饰的多囊泡脂质体平均粒径分别为22.5和32.2 μm；PEG2000修饰和未经过PEG2000修饰的MVLs包封率分别为（85.1±11.2）%和（80.7±9.4）%；2种脂质体体外释放符合一级释药规律，半衰期t1/2分别为5.8和19.9 h，增加了3.4倍。结论 PEG2000修饰多囊泡脂质体包封率高，并具有良好的缓释作用。

Preparation and Characterization of Tramadol PEG2000-coated Multivesicular Liposomes for Intramuscular Sustained Release

OBJECTIVE To prepare tramadol PEG2000-coated multivesicular liposomes with high encapsulation efficiency and sustained-release character. METHODS Tramadol multivesicular liposomes were prepared by double emulsification method and the formulation was optimized by orthogonal design. The encapsulation efficiency, the particle size of the liposomes and release of the tramadol from the liposomes were studied in vitro. The release characteristics of tramadol from multivesicular liposome in PBS (pH 6.8) were investigated. RESULTS The entrapment efficiency of the PEG2000-coated multivesicular liposomes and PEG2000-coated multivesicular liposomes of tramadol was （85.1±11.2）% and （80.7±9.4）%, the mean particle size was about 22.5 and 32.2 μm, respectively. The release profile in vitro fitted with a first-order equation. The t1/2 of tramadol PEG2000-coated multivesicular liposomes is 19.9 h, which is 5.8 h for multivesicular liposomes. CONCLUSION The tramadol PEG2000-coated multivesicular liposomes showed high encapsulation efficiency and sustained release character.