高内相/自乳液聚合的共轭亚油酸低聚体的囊泡化及稳定性

采用自乳化法制备了高内相共轭亚油酸(CLA)的水包油(O/W)乳液, 并通过热引发乳液聚合反应得到共轭亚油酸低聚体(oligo-CLA); 将oligo-CLA用于自组装脂肪酸囊泡(FAV). 透射电子显微镜和动态激光光散射表征结果均表明, 在pH=8.6~13范围内得到了囊泡粒径为10~30 nm的FAV, 此结果对提高FAV的pH适应性具有理论意义. 自乳液聚合实验结果表明, 该高内相自乳化/热引发低聚反应策略可以使浓度高达75.3%(质量分数)的CLA完成无外加表面活性剂乳液聚合, 并使共轭双键总自交联率达到33%且控制oligo-CLA的平均聚合度约为6, 对规模化生产oligo-CLA及构筑FAV具有实用价值. 与CLA相比, oligo-CLA具有更好的低温溶解性, 由其自组装的FAV具有更好的环境适应性, 如耐酸性和抗钙皂能力, 而且显示出较好的钙响应囊泡体积膨胀率; 以极少量非离子表面活性剂Span 40或AEO₂辅助oligo-CLA形成的杂化囊泡具有更宽的pH适应性. 因此, 所制备的FAV在药物释放体系、 日用化学产品、 家用洗涤剂和个人护理产品中具有更广阔的应用前景.

Vesiculation and Stability: Oligomer of Conjugated Linoleate Acids Prepared by High Internal Phase Self-emulsion Polymerization†

High internal phase O/W emulsion of conjugated linoleic acids(CLA) was prepared by self-emulsifying technology, and oligomer of CLA(oligo-CLA) was obtained by thermal self-emulsion polymerization(SEP) of the above emulsion. Furthermore, fatty acid vesicles(FAV) self-assemble by the oligo-CLA showing 10—30 nm diameter at pH=8.6—13 that was revealed by both transmission electron microscopy and dynamic light scattering, which has theoretical significance for FAV stable at a broader pH range. The experimental results show that free-surfactant emulsion polymerization was completed in the high internal phase emulsion of 75.3%(mass fraction) CLA according to the unique self-emulsification/thermal oligomerization strategy, achieving 33% total self-crosslinking degree and the target oligo-CLA with an average polymerization degree of 6, which is instructive for scaling up oligo-CLA and FAV preparation. The oligo-CLA has better low temperature solubility in comparison with CLA itself, and the FAV self-assembling by it has stronger resistance to acidic and calcium conditions and shows calcium responsive size-tunable features. Moreover, the hybrid vesicles of oligo-CLA with a small amount of Span 40 or AEO₂ additives show even broader pH windows for vesiculation. Therefore the FAV self-assembling by oligo-CLA should have a wider application prospect in drug delivery systems, daily chemical products, and household detergents and personal care products.