Hirsjärvi Samuli, Peltonen Leena, Hirvonen Jouni
Division of Pharmaceutical Technology, Faculty of Pharmacy, P.O. Box 56, FI-00014 University of Helsinki, Finland.
Colloids Surf B Biointerfaces. 2006 Apr 15;49(1):93-9. doi: 10.1016/j.colsurfb.2006.03.009. Epub 2006 Apr 17.
Low molecular weight (M(w)) poly(L-lactic acid) (PLA) nanoparticles were coated with polyelectrolytes (PEs) by layer-by-layer (LbL) technique using a filtration approach. Poly(allylamine hydrochloride) and poly(sodium 4-styrenesulfonate) were applied as PEs in coating. LbL coating is aimed to use in producing (nano)particulate drug delivery systems with improved biocompatibility and sustained or targeted release of drug substances. Nanoparticles of rapidly biodegradable polymers, like the low M(w) PLA, open up a possibility to control the release of the encapsulated substance by the coating, but set challenges to the coating process due to increased aggregation tendency and degradation rate of the polymer. When the core PLA nanoparticles were prepared by nanoprecipitation, surface properties of the nanoparticles were affected by solvent selection. Successful LbL coating of the PLA nanoparticles was obtained only with chloroform, but not with dichloromethane as the solvent during nanoprecipitation. Reason for this was found to be the more charged surface of the nanoparticles prepared with chloroform compared to the nanoparticles prepared with dichloromethane.
采用过滤法通过层层（LbL）技术用聚电解质（PEs）包覆低分子量（M(w)）聚（L-乳酸）（PLA）纳米颗粒。聚（烯丙胺盐酸盐）和聚（4-苯乙烯磺酸钠）被用作包覆中的聚电解质。层层包覆旨在用于生产具有改善的生物相容性以及药物物质持续或靶向释放的（纳米）颗粒药物递送系统。快速可生物降解聚合物的纳米颗粒，如低M(w) PLA，为通过包覆控制包封物质的释放提供了可能性，但由于聚合物聚集倾向增加和降解速率加快，给包覆过程带来了挑战。当通过纳米沉淀法制备核心PLA纳米颗粒时，纳米颗粒的表面性质受溶剂选择的影响。仅在纳米沉淀过程中使用氯仿作为溶剂时，才能成功实现PLA纳米颗粒的层层包覆，而使用二氯甲烷则不行。发现其原因是与用二氯甲烷制备的纳米颗粒相比，用氯仿制备的纳米颗粒表面电荷更多。
