Department of Chemistry and Energy Engineering, Faculty of Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo, 158-8557, Japan.
Department of Chemistry and Energy Engineering, Faculty of Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo, 158-8557, Japan.
Colloids Surf B Biointerfaces. 2017 Nov 1;159:412-418. doi: 10.1016/j.colsurfb.2017.07.092. Epub 2017 Aug 1.
We investigated the extent of potential applicability of our recently developed method for preparing lipid vesicles [T. Kuroiwa et al., J. Am. Oil Chem. Soc., 93 (2016) 421], designated as the multiple emulsification-solvent evaporation method, with the intention of controlling the vesicle diameter and achieving high entrapment efficiency for water-soluble compounds. Using this method, the diameter of lipid vesicles could be varied by selecting the methods for preparing the primary water-in-oil emulsion, which contained water droplets as templates for the internal water phases of lipid vesicles. We obtained lipid vesicles with mean diameters of 0.2-4.4μm from water-in-oil-in-water multiple emulsions after solvent evaporation. A high entrapment yield of calcein, a water-soluble fluorescent dye, into the lipid vesicles was obtained for each vesicle sample, depending on their diameter and the type of emulsifier added to the external water phase. The use of polymeric emulsifier was more effective in achieving a high entrapment yield. The obtained lipid vesicles were powderized via freeze-drying. Vesicles could be powderized while maintaining their original diameter, as confirmed by scanning electron microscopy. Furthermore, the powderized vesicles could be rehydrated and resuspended without significant change in their diameter. However, the entrapment yield of calcein decreased after freeze-drying and rehydration. The calcein leakage during the freeze-drying followed by rehydration could be suppressed by adding an appropriate amount of trehalose as a lyoprotectant.
我们研究了我们最近开发的用于制备脂质体的方法[T. Kuroiwa 等人，美国油脂化学学会杂志，93（2016）421]的潜在适用性，该方法被称为多次乳化-溶剂蒸发法，目的是控制囊泡直径并实现水溶性化合物的高包封效率。使用这种方法，可以通过选择制备初级油包水乳液的方法来改变脂质体的直径，该乳液含有作为脂质体内部水相模板的液滴。我们通过溶剂蒸发从油包水包水多重乳液中获得了平均直径为 0.2-4.4μm 的脂质体。根据每个囊泡样品的直径和添加到外部水相中的乳化剂的类型，我们获得了 calcein（一种水溶性荧光染料）包封到脂质体中的高包封产率。使用聚合物乳化剂更有效地实现了高包封产率。通过冷冻干燥将获得的脂质体粉末化。通过扫描电子显微镜确认，囊泡可以在保持其原始直径的情况下粉末化。此外，粉末化的囊泡可以再水合而其直径没有明显变化。然而，在冷冻干燥和再水合后，calcein 的包封产率降低。通过添加适量的海藻糖作为冷冻保护剂，可以抑制冷冻干燥和再水合过程中的 calcein 泄漏。
