两亲多糖纳米胶束作为药物缓释载体的制备及释药研究

【目的】合成葡聚糖接枝聚乳酸(DEX-g-PLA)两亲多糖共聚物,检测其纳米胶束的相关参数,初步探讨其纳米胶束在药物缓释方面的应用。【方法】采用偶联法合成DEX-g-PLA。用透射电子显微镜观察所形成胶束的形态;用动态光散射仪观察纳米胶束有效粒径的变化。体外药物释放实验考察其对不同水溶性药物的缓释作用。MTT法考察其生物相容性。【结果】DEX-g-PLA纳米胶束,呈球形,粒径在50～190nm之间,其有效粒径随聚乳酸含量的增加而增大。载药纳米胶束对疏水性维生素B2的缓释效果优于亲水性的5-氟尿嘧啶。MTT结果显示该纳米胶束具有良好的生物相容性。【结论】DEX-g-PLA纳米胶束具有良好的生物相容性,对疏水性药物的缓释作用优于亲水性药物,有望成为新型药物缓释载体。

Preparation and Drug Controlled-release of Biodegradable Amphiphilic Polysaccharide Nano-micelles as Drug Delivery Systems

Objective To investigate the preparation of polylactide-grafted dextran copolymer(DEX-g-PLA),and to detect their correlative parameters and explore the application of nano-micelles for drug controlled-release.Methods The polylactide-grafted dextran copolymer(DEX-g-PLA)was synthesized in a bulk lactide polymerization reaction using dextran derivative as macroinitiator and stannous octoate as catalyst.The surface morphology of the resulting nano-micelles was characterized by transmission electron microscopy and particle size was measured by dynamic light scattering.The controlled-release of drugs of different water-solubility was tested by in-vitro release studies,and the biocompatibility of nano-micelles was measured by MTT assay in vitro.Results The DEX-g-PLA nano-micelles were of round or elliptical shape and their average diameters ranged from 50 nm to 190 nm,which were increased with the increase of content of PLA in micelles.The in-vitro release studies indicated that the release of hydrophobic vitamin B2 from nano-micelles was obviously more sustained than that of hydrophilic 5-Fluorouracil.MTT assay suggested that DEX-g-PLA nano-micelles were of fine biocompatibility.Conclusion The release of hydrophobic drugs from the biocompatible micelles of DEX-g-PLA is obviously more sustained than that of hydrophilic drugs,suggesting it would be a promising carrier for drug delivery systems.