聚乙二醇—聚己内酯—聚甲基丙烯酸-N,N-二乙氨基乙酯作为膜岛素缓释载体的研究

发布时间：2018-06-07 09:32

  本文选题：胰岛素 + pH敏感　； 参考：《南方医科大学》2017年硕士论文

【摘要】：研究背景和目的:胰岛素(insulin,INS)作为治疗糖尿病的常用、必备药物,存在生物膜渗透性差、半衰期短、易被胃肠道强酸、碱、酶灭活等缺陷,经口服或其他非注射途径给药的生物利用度低,故临床仍采取注射给药的方式。但长期频繁注射易造成峰谷浓度波动大,患者顺应性差。因此,为了发挥INS理想的治疗效果,研究合适的药物载体,发展INS缓控释给药体系是极其有必要的。故本文设计了一种pH敏感两亲性三嵌段聚合物,研究了其作为INS载体的载药、释药性能以及体内降血糖活性,以期为INS的缓控释制剂开发提供参考。方法:1.结合ROP和ATRP反应合成不同分子量的三嵌段聚合物,并用FT-IR和1H-NMR表征结构,芘荧光探针法测定临界聚集浓度(CAC);2.采用纳米沉淀技术制备载INS纳米粒,动态光散射法(DLS)测定粒径,透射电镜(TEM)观察粒子形态;3.BCA法考察载药情况和体外释放行为,并以7个药物释放模型进行拟合、分析,初步探讨载INS纳米粒的体外释放机制;4.MTT法考察聚合物纳米粒对L929细胞的毒性;5.建立STZ诱导的糖尿病大鼠模型,考察载INS纳米粒的体内降血糖效果。结果:1.FT-IR和1H-NMR结果确证了聚合物的结构为聚乙二醇-聚己内酯-聚甲基丙烯酸-N,N-二乙氨基乙酯(mPEG-PCL-PDEAEMA),其分子组成与预期设计一致说明了合成方法稳定可控。聚合物的CAC值比普通小分子表面活性剂低3～6个数量级,表明其形成的纳米粒具有较强的结构稳定性。2.聚合物自组装行为具有pH敏感,形成的纳米粒粒径和形态会随pH变化而改变。负载INS后纳米粒的粒径明显增大,呈球形核壳结构且粒径分布均一。3.载药实验表明90%wt投料比组的包封率(EE%)和载药率(DL%)显著优于 70%wt(P0.001)、50%wt(P0.001)、20%wt(P0.001),其最高 EE%和DL%可达81.99±1.77%和42.46±0.53%。体外释放结果显示载INS纳米粒有良好的缓释行为且呈现pH敏感性,在pH 6.0释放介质中的释药速率明显高于pH 7.4。其中,pH 6.0中的释药过程为Fick's扩散,pH 7.4中的释药过程为Fick's扩散和骨架溶蚀。载INS纳米粒在二者中的释放行为均与Weibull模型拟合效果最好,提示制剂存在释放延迟,并且增长聚合物的疏水链段能有效降低药物突释量,延缓释放。4.浓度≤0.4mg/ml时,聚合物纳米粒对L929细胞无毒性。5.与INS相比,载INS纳米粒在体内呈现一定的缓释效果且降血糖时间明显延长。其中,INS-mPEG114-PCL86-PDEAEMA53纳米粒组和INS-mPEG114-PCL114-PDEAEMA53纳米粒组的降血糖时间可持续12h和48h,而INS组只能维持4h。结论:本文制得的聚合物载INS纳米粒的理化性质好,包封率和载药率均较高,体外有良好缓释且体内降血糖时间明显延长。故pH敏感两亲性三嵌段聚合物mPEG-PCL-PDEAEMA有望成为理想的INS缓释载体。
[Abstract]:Background and objective: as a commonly used and necessary drug for the treatment of diabetes mellitus, INS has some defects such as poor permeability of biofilm, short half-life, and easily inactivated by gastrointestinal acid, alkali and enzyme. The bioavailability of oral or other non-injection drugs is low, so injection is still used in clinic. However, frequent injection for a long time can cause large fluctuation of peak and valley concentration and poor compliance of patients. Therefore, in order to give full play to the ideal therapeutic effect of INS, it is extremely necessary to study the appropriate drug carrier and develop the drug delivery system of INS. In this paper, a pH sensitive amphiphilic triblock polymer was designed to study the drug delivery, drug release and hypoglycemic activity of INS carrier in order to provide a reference for the development of slow and controlled release preparation of INS. Method 1: 1. Triblock polymers with different molecular weights were synthesized by the reaction of ROP and ATRP. The structure was characterized by FT-IR and 1H-NMR. The critical concentration of CACX 2 was determined by pyrene fluorescence probe method. INS nanoparticles were prepared by nano-precipitation technique. The particle size was measured by dynamic light scattering (DLS). The morphology of particles was observed by TEM. 3. BCA method was used to investigate the drug loading and in vitro release behavior. Seven drug release models were fitted and analyzed. A preliminary study on the release mechanism of INS nanoparticles in vitro. 4. The toxicity of polymer nanoparticles to L929 cells was investigated by MTT assay. STZ induced diabetic rat model was established to investigate the hypoglycemic effect of INS loaded nanoparticles in vivo. Results 1. The structure of the polymer was confirmed by FT-IR and 1H-NMR. The molecular composition of the polymer was stable and controllable. The molecular composition of the polymer was consistent with that of the expected design and the molecular composition of the polymer was confirmed to be pegylglycol-poly (caprolactone) -polymethacrylic acid-N-diethylaminoethyl ester (mPEG-PCL-PDEAEMAA). The CAC value of the polymer is 3 ~ 6 orders of magnitude lower than that of the ordinary small molecular surfactants, which indicates that the nanoparticles formed by the polymer have strong structural stability. 2. The self-assembly behavior of polymer is pH sensitive, and the particle size and morphology will change with the change of pH. After INS loading, the particle size of nanoparticles increased obviously, with spherical core-shell structure and uniform particle size distribution. The results of drug loading test showed that the encapsulation rate and drug loading rate of 90%wt group were significantly better than that of 70 WTT P0.001 and 50 WTX P0.001 and 20 WTT P0.001C, and the highest EE% and DL% reached 81.99 卤1.77% and 42.46 卤0.53% respectively. The drug loading test showed that the drug loading rate was significantly higher than that in the control group (P 0.001), and the highest EE% and DL% were 81.99 卤1.77% and 42.46 卤0.53%, respectively. The results of in vitro release showed that INS nanoparticles had good sustained release behavior and showed pH sensitivity, and the release rate in pH 6.0 release medium was significantly higher than that in pH 7.4. The drug release process in pH 6.0 is Fick's diffusion and release process in pH 7.4 is Fick's diffusion and skeleton dissolution. The release behavior of the nanoparticles loaded with INS was best fitted to the Weibull model, indicating that there was a release delay in the preparation, and the hydrophobic segment of the increased polymer could effectively reduce the amount of drug release and delay the release of .4. When the concentration 鈮，

本文编号：1990703