Matsumoto Akihiro, Murao Satoshi, Matsumoto Michiko, Watanabe Chie, Murakami Masahiro
Laboratory of Pharmaceutics, Faculty of Pharmacy, Osaka Ohtani University.
Drug Discov Ther. 2016;10(6):307-313. doi: 10.5582/ddt.2016.01230.
The feasibility of fabricating Janus particles based on phase separation between a hard fat and a biocompatible polymer was investigated. The solvent evaporation method used involved preparing an oil-in-water (o/w) emulsion with a mixture of poly (lactic-co-glycolic) acid (PLGA), hard fat, and an organic solvent as the oil phase and a polyvinyl alcohol aqueous solution as the water phase. The Janus particles were formed when the solvent was evaporated to obtain certain concentrations of PLGA and hard fat in the oil phase, at which phase separation was estimated to occur based on the phase diagram analysis. The hard fat hemisphere was proven to be the oil phase using a lipophilic dye Oil Red O. When the solvent evaporation process was performed maintaining a specific volume during the emulsification process; Janus particles were formed within 1.5 h. However, the formed Janus particles were destroyed by stirring for over 6 h. In contrast, a few Janus particles were formed when enough water to dissolve the oil phase solvent was added to the emulsion immediately after the emulsification process. The optimized volume of the solvent evaporation medium dominantly formed Janus particles and maintained the conformation for over 6 h with stirring. These results indicate that the formation and stability of Janus particles depend on the rate of solvent evaporation. Therefore, optimization of the solvent evaporation rate is critical to obtaining stable PLGA and hard fat Janus particles.
研究了基于硬脂与生物相容性聚合物之间的相分离制备Janus粒子的可行性。所采用的溶剂蒸发法包括制备水包油（o/w）乳液，其中以聚（乳酸-乙醇酸）共聚物（PLGA）、硬脂和有机溶剂的混合物作为油相，聚乙烯醇水溶液作为水相。当溶剂蒸发以在油相中获得一定浓度的PLGA和硬脂时，Janus粒子形成，基于相图分析估计此时会发生相分离。使用亲脂性染料油红O证明硬脂半球为油相。当在乳化过程中保持特定体积进行溶剂蒸发过程时，在1.5小时内形成Janus粒子。然而，搅拌超过6小时会破坏形成的Janus粒子。相比之下，乳化过程后立即向乳液中加入足以溶解油相溶剂的水时，会形成少量Janus粒子。溶剂蒸发介质的优化体积主要形成Janus粒子，并在搅拌下保持构象超过6小时。这些结果表明Janus粒子的形成和稳定性取决于溶剂蒸发速率。因此，优化溶剂蒸发速率对于获得稳定的PLGA和硬脂Janus粒子至关重要。
