溫敏性三嵌段共聚合物PLGA-PEG-PLGA的合成與性質之研究

本論文係以具親水性的聚乙二醇(PEG)為起始劑，辛酸亞錫(Sn(Oct)2)為共起始劑，與丙交酯(LA)及乙交酯(GA)行開環共聚合反應，製備一系列溫敏感性PLGA-PEG-PLGA三嵌段式共聚物。其中PEG係以PEG1000、PEG1500等重量比例混合而成。本論文共分三部分，第一部分為控制親水性PEG(Y)與疏水性PLGA(X)分子量比為2.5與3.0，及不同LA與GA比製備一系列溫敏感性PLGA-PEG-PLGA三嵌段式共聚物。主要探討不同LA/GA比對此三嵌段共聚合物水溶液性質性質的影響。如臨界微胞溫度(CMT)、臨界微胞濃度(CMC)，相圖等。第二部分為固定LA/GA比為75/25製備一系列溫敏感性PLGA-PEG-PLGA三嵌段式共聚物，探討不同疏水鏈(PLGA)鏈長對其水溶液性質的影響如臨界微胞溫度(CMT)、臨界微胞濃度(CMC)，相圖等。第三部分則製備一系列溫敏感性PLGA-PEG-PLGA三嵌段式共聚物，其LA/GA比固定為75/25，X/Y固定為2.5，接著此三嵌段共聚物以monomethoxy poly(ethylene glycol) (mPEG)封端，探討對其水溶液性質及降解性的影響

關鍵字

丙交酯/乙交酯； ABA溫敏性三嵌段聚合物；溫敏性水凝膠

並列摘要

ABSTRACT In this study, a series of biodegradable triblock amphiphilic and thermosensitive PLGA-PEG-PLGA copolymers were prepared by using hydrophilic poly(ethylene glycol) (PEG) as macro-initiator and stannous octoate as a catalyst, lactide (LA) and glycolide (GA) via ring opening polymerization where the used PEG was equally weight ratio mixed with PEG1000 and PEG1500. This research was subdivided into three parts. In first part, a series of biodegradable triblock amphiphilic and thermosensitive PLGA-PEG-PLGA copolymers were prepared. Their molecular weight ratios of hydrophobic PLGA(X) and hydrophilic PEG (Y) were fixed at 2.5 and 3.0. In addition, the various molar ratios of LA and GA were designed. The effect of the different molar ratios of LA/GA on the aqueous properties, such as critical micellization temperature (CMT), critical micellization concentration (CMC), and sol-gel phase diagram etc, of the present triblock copolymers was investigated. In second part, a series of biodegradable triblock amphiphilic and thermosensitive PLGA-PEG-PLGA copolymers were prepared. Their molar ratio of LA and GA in the triblock copolymer was fixed at 75/25. The effect of different hydrophobic chain lengths in the PLGA-PEG-PLGA copolymers on the aqueous properties, such as critical micellization temperature (CMT), critical micellization concentration (CMC), and sol-gel phase diagram etc, of the present triblock copolymers was investigated. In third part, a series of biodegradable triblock amphiphilic and thermosensitive PLGA-PEG-PLGA copolymers were prepared. Their molar ratio of LA and GA in the triblock copolymer was fixed at 75/25 and hydrophobic chain length PLGA(X) and hydrophilic chain length PEG (Y) were fixed at 2.5. Then, these triblock copolymers was chain-end blocked with monomethoxy poly(ethylene glycol) (mPEG) to form mPEG-PLGA-PEG-PLGA-mPEG block copolymer and their aqueous properties and biodegradation behavior was investigated.