Wang Ting, Deng Yingjie, Geng Yehui, Gao Zibin, Zou Jianping, Wang Zhixuan
Department of Pharmaceutical Sciences, Shenyang Pharmaceutical University, P.O. Box 52, No. 103 Wenhua Road, Shenyang City, Liaoning Province 110016, PR China.
Biochim Biophys Acta. 2006 Feb;1758(2):222-31. doi: 10.1016/j.bbamem.2006.01.023. Epub 2006 Feb 28.
A novel method is described for the preparation of sterile submicron unilamellar liposomes. The method is based on the lyophilization of double emulsions containing disaccharides as lyoprotectants in both the inner and outer aqueous phase. Using various phospholipids or mixtures of lipids as emulsifiers, the double emulsions can be prepared by a two-step emulsification, including hydrophilic agents in the inner aqueous phase or lipophilic agents in the oil phase. Then, the double emulsions are lyophilized after sterilization by passing them through a 0.22-microm pore filter. Rehydration of the lyophilized products results in liposomes with a relatively high encapsulation efficiency (for calcein, 87%; 5-fluorouracil, 19%; flurbiprofen, 93%) and a size below 200 nm measured by the dynamic light scattering technique (DLS) and the atomic force microscopy (AFM). The liposomes were found to be unilamellar from freeze-fracture electron micrographs and X-ray diffraction patterns. In addition, the liposomes can be reconstituted just before use by rehydration of the lyophilized products which are relatively stable. Thus, this reproducible and simple technique can be used to prepare sterilized, submicron unilamellar liposomes with a relatively high encapsulation efficiency, and excellent stability during long-term storage.
本文描述了一种制备无菌亚微米单层脂质体的新方法。该方法基于对含有二糖作为冻干保护剂的双重乳液进行冻干，二糖同时存在于内水相和外水相中。以各种磷脂或脂质混合物作为乳化剂，通过两步乳化法制备双重乳液，在内水相中加入亲水试剂或在油相中加入亲脂试剂。然后，双重乳液在通过0.22微米微孔过滤器灭菌后进行冻干。冻干产物复水后得到脂质体，通过动态光散射技术（DLS）和原子力显微镜（AFM）测量，其包封率相对较高（对于钙黄绿素，为87%；对于5-氟尿嘧啶，为19%；对于氟比洛芬，为93%），粒径小于200nm。从冷冻断裂电子显微镜照片和X射线衍射图谱可以看出，脂质体为单层结构。此外，相对稳定的冻干产物复水后即可在使用前重新制备脂质体。因此，这种可重复且简单的技术可用于制备具有较高包封率且在长期储存期间具有出色稳定性的无菌亚微米单层脂质体。
