一种新型热敏聚乳酸微球的制备与表征

背景：目前,基于聚乳酸的智能型微球是药物可控释放研究领域的热点。 目的：制备一种温度响应可控、生物可降解的微球载体。 方法：以甲基丙烯酸-2-羟乙酯作为丙交酯开环的引发剂,采用辛酸亚锡作为催化剂,并调节乳酸与甲基丙烯酸乙酯的比例,得到了不同分子质量的带双键聚乳酸(PDLLA-EMA)。以甲苯为溶剂,采用溶液合成法,自由基反应引发含有双键的聚乳酸以及N,N-异丙基丙烯酰胺共聚,成功制得了可降解温敏型共聚物(PNIPA-g-PDLLA-EMA)。采用复乳法,将PNIPA-g-PDLLA-EMA制成了微球。 结果与结论：实验制得PNIPA-g-PDLLA-EMA材料的热响应温度范围为35~42 ℃,基于该材料制得的微球粒径范围为(13.70±0.70)~(28.90±0.50) μm,粒径变化率为(138.7±4.20)%~(170.0±10.00)%,与同类材料相比,该微球已具备了应用于生物医学的潜在条件。关键词：智能型微球;可生物降解;聚乳酸;制备;载体 缩略语注释：PNIPAm：Poly N-isopropylacrylamide,聚(N-异丙基丙烯酰胺) doi:10.3969/j.issn.1673-8225.2012.16.015

Preparation and characterization of a new-type thermal-sensitive polylactic acid microsphere

BACKGROUND: At present, the research of controlled drug release has been focused on intelligent microspheres based on polylactic acid. OBJECTIVE: To prepare a temperature-controllable and biodegradable microsphere carrier. METHODS: First, 2-hydroxyethyl methacrylate was used as evocating agent for ring-opening polymerization of lactide, and stannous octoate used as catalyst. Through regulating the proportion of lactide and ethyl methacrylate, a double-bound polylactic acid ethyl methacrylate (PDLLA-EMA) of different molecular masses was obtained. After that, methylbenzene was used as solvent, and the copolymerizations of PDLLA-EMA with double bound and poly N-isopropylacrylamide (PNIPAm) were initiated by free radical reaction with a solution synthesis method, and then the biodegradable and temperature-sensitive     PNIPA-g-PDLLA-EMA was prepared successfully. At last, the thermal-sensitive polylactic acid microspheres were prepared by a double emulsion method. RESULTS AND CONCLUSION: The thermal sensitive temperature of PNIPA-g-PDLLA-EMA prepared was in a range of   35-42 ℃. The range of microsphere particle size was (13.70±0.70) to (28.90±0.50) μm, and the change rate of particle size was (138.7±4.20)% to (170.0±10.00)%. Compared with other same type materials, this kind of microsphere has potentialities in biomedicine.