离子诱导结合化学交联法制备壳聚糖纳米粒及其作为药物靶向缓释载体的初步研究

Preparation of Chitosan Nanoparticles for Targeting and Sustained Drug Delivery System by Ion-induced Combined with Chemical Crosslinking

目的制备粒径相对可控的壳聚糖纳米粒,探索其在药物缓释体系中的应用。方法以多聚磷酸钠为离子诱导剂、戊二醛为化学交联剂,通过离子诱导结合化学交联法,制备壳聚糖纳米粒;在1-乙基-（3-二甲氨基丙基）碳二亚胺盐酸盐（EDC）作用下,分别进行丝裂霉素载药以及聚乙二醇（PEG）,叶酸修饰;另外,对载药纳米粒子进行不同pH条件下的体外释药实验;对PEG,叶酸修饰的壳聚糖纳米粒罗丹明B荧光标记后,进行激光共聚焦以及活体成像实验。结果离子诱导交联法可以获得粒径范围在200~500 nm的壳聚糖纳米粒;丝裂霉素载药量可以达到25%,包封率为50%,体外释药呈现突释和缓释双相特征,并且随着pH的升高释药明显加快;未经修饰的、叶酸修饰的以及PEG和叶酸修饰的纳米粒都能有效的进入Hela细胞,而单独PEG修饰的却很少进入细胞内;叶酸修饰的纳米粒有明显的靶向作用,PEG修饰的纳米粒可以明显延长实验裸鼠血液中循环时间。结论采用离子诱导结合化学交联法可以获得粒径可控、稳定、适合于主动靶向给药的壳聚糖纳米粒。

OBJECTIVE To prepare chitosan nanoparticle with controllable size and investigate its applications to targeting and sustained drug delivery system.METHODS The combination of an ion-induced and chemical crosslinking method was used to prepare chitosan nanoparticles,and mitomycin C,PEG and folic acid were bound covalently on the surface of chitosan nanoparticles in the presence of 1-ethyl-3-（3-dimethyllaminopropyl） carbodiimide hydrochloride（EDC）,respectively.In vitro drug release test was carried out in different pH PBS solution.Confocal laser scanning microscope of Hela cell and in vivo imaging test were carried out using PEG and folic acid-modified chitosan nanoparticles labeled by Rhodamine B.RESULTS The diameter was in the range of 200 and 500 nm,the drug-loading capability and entrapment efficiency were 25% and 50%,respectively.The drug release was somewhat biphasic with an initial burst effect,followed by a subsequent slower release.Furthermore,increasing pH of the medium resulted in a faster release rate.Blank chitosan nanoparticles,folic acid modified and both folic acid and PEG-modified nanoparticles were effectively uptaken by Hela cells,while the single PEG-modified nanoparticles rarely entered the cell.By live imaging techniques,folic acid-modified nanoparticles had a clear targeting character.While,the PEG-modified chitosan nanoparticles enhanced circulation time in the bloodstream of mice.CONCLUSION By the method of ion-induced combined with chemical crosslinking,steady chitosan nanoparticles with controlable size were obtained and suitable for active targeting drug delivery.