共聚物压敏胶的链段结构对其力学性能和药物释放的调控

高分子压敏胶的多层次性结构，如结构单元组成、分子链长短、亲疏水性和聚集态结构等对药物的释放具有显著的影响．利用可逆加成．断裂链转移（RAFT）聚合技术，合成了一系列结构可控的两嵌段或三嵌段共聚物压敏胶．通过高效凝胶渗透色谱、核磁等手段对嵌段聚合物压敏胶进行了表征．对上述压敏胶的力学性能的研究表明，聚丙烯酸异辛酯．苯乙烯．甲基丙烯酸羟乙酯（PEHA—St—HEMA）三嵌段共聚物的初粘力、持粘力和180°剥离力分别为8号钢球、40．3min和19．81N／（25mm），非常适合用于经皮黏附．再以布洛芬和5-氟尿嘧啶为药物模型，研究压敏胶多层次结构对不同药物释放的影响和调控作用．结果表明，压敏胶的结构变化对药物释放具有显著的影响，亲水性链段的引入可以调控亲水性药物在基质中的释放行为．该研究可为基质的设计和充分发挥聚合物多层次结构在经皮给药中的作用提供指导．

Effect of Segment Structure on Mechanical Properties and Drug Release Behavior of Copolymer Pressure Sensitive Adhesives

The multilayer-molecular structures of polymeric pressure sensitive adhesives （PSAs）, such as structural element, chain length, hydrophilic-hydrophobic property and aggregation structure, have significant impact on drug release in transdermal drug delivery system （TDDS）. Reversible addition-fragmentation chain transfer （RAFT） po- lymerization was used to prepare a series of diblock or triblock copolymer PSAs with well-defined structure in order to investigate the effect of chain segment structures on the mechanical properties of the PSAs and drug release behavior in PSAs. The structure and the molecular weight of the prepared block eopolymers were characterized by ~HNMR and GPC. The mechanical properties, such as tack force, static shear resistance and 180° peel strength, were also measured. The results show that tack force, static shear resistance and 180~ peel strength of the triblock copolymer poly （2- ethylhexyl acrylate-styrene-β-hydroxyethyl methacrylate） （PEHA-St-HEMA） are No.8, 40.3 min and 19.81 N/（25 mm）, respectively, which are suitable for use in TDDS. Subsequently, ibuprofen and 5-fluorouracil were chosen as drug model to estimate the drug release behavior in the obtained PSAs in vitro. The results show that the multilayer molecular strucures of PSAs can significantjy influence the drug release and the introduction of hydrophilic chain seg ment can facilitate the release of hydrophilic drug. These research results can serve as a powerful tool to study and manipulate the drug release behavior in the polymeric PSAs.