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采用可逆加成-断裂链转移(RAFT)聚合合成了以丙烯酸异丁酯(IBA)、甲基丙烯酸2-二甲氨乙酯(DMAEMA)无规共聚嵌段与聚丙烯酸-2-羟丙酯(PHPA)组成的两亲性两嵌段共聚物(P(IBA-co-DMAEMA)-b-PHPA),并用凝胶渗透色谱(GPC)、核磁共振波谱(1 H-NMR)及红外光谱(FTIR)对其进行了结构和组成表征.这种共聚物在水溶液介质下能够自组装形成稳定的聚合物胶束,通过荧光探针技术测得其低临界胶束浓度(CMC)约为2.1 mg/L.透射电镜(TEM)和动态激光光散射(DLS)测定结果表明,P(IBA-co-DMAEMA)-b-PHPA在水溶液中自组装形成的胶束呈球形核壳结构,其平均动力学直径处于110～136 nm之间,且呈均匀较窄分布.以该聚合物胶束为载体、叶酸(FA)为模型药物,模拟人体生理环境进行药物体外释放研究.结果表明,叶酸负载量及负载效率分别高达38%和76%.在温度37℃、离子强度I=0.15 mol/kg、pH值分别为2.0、7.4、9.2磷酸缓冲溶液(PBS)下,FA在40 h内的释放都相对较快,释放速率随pH的增加依次增大.随后释放变缓,最大累积释放率分别为36%,61%和80%.
The copolymers of isobutyl acrylate (IBA), DMAEMA random copolymer block and 2-hydroxypropyl acrylate were synthesized by reversible addition-fragmentation chain transfer (RAFT) (P (IBA-co-DMAEMA) -b-PHPA) was synthesized and characterized by gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (1 H-NMR) and infrared spectroscopy FTIR), the copolymer was self-assembled into a stable polymer micelle under the condition of aqueous solution, and its low critical micelle concentration (CMC) was about 2.1 mg / L. The results of transmission electron microscopy (TEM) and dynamic laser light scattering (DLS) show that the micelles formed by the self-assembly of P (IBA-co-DMAEMA) -b-PHPA in aqueous solution have a spherical core- The diameter of the study was between 110 and 136 nm with a uniform and narrow distribution.The folic acid (FA) was used as a model drug to simulate the physiological environment of human body to study the drug release in vitro.The results showed that the folic acid load And the loading efficiency were as high as 38% and 76%, respectively.When the temperature was 37 ℃, the ionic strength I = 0.15 mol / kg, the pH values were 2.0, 7.4 and 9.2 respectively The solution (PBS), FA released within 40 h were relatively faster release rate increases with increase in pH sequentially Subsequently slow release, the maximum accumulated released rate was 36%, 61% and 80%, respectively.