氰基丙烯酸酯包裹胰岛素纳米颗粒的结构

 目的：为得到稳定有效的口服胰岛素制剂，对氰基丙烯酸异丁酯包裹胰岛素的机制进行了一系列的体外研究。方法：用凝胶层析法分离纳米包裹颗粒和游离的胰岛素，结合RIA法、放射标记示踪以及作者设计的“抗体捕捉”实验，以阐明氰基丙烯酸异丁酯包裹胰岛素纳米颗粒的结构。结果：大部分胰岛素分子（80％）与形成的纳米包裹颗粒紧密相连，处于包裹颗粒的表面，可以用RIA法测到，而且对蛋白酶降解有一定抵抗作用。用乙腈溶解包裹颗粒，大部分胰岛素分子（84％）并不在溶液中，而与聚合物相连。用抗胰岛素抗体与包裹胰岛素的颗粒反应，可以在电镜下观察到包裹颗粒被抗体捕获。结论：这些结果表明胰岛素分子并未被包裹于颗粒内部，也不是以简单吸附的方式与包裹颗粒相连，而可能通过共价结合的方式与氰基丙烯酸酯聚合物相结合。

Structure of insulin-encapsulated polyalkylcyanoacrylate nanoparticle

OBJECTIVE: To elucidate the mechanism of protein drugs encapsulated by polyalkylcyanoa crytale(PACA)nanoparticles,specifically,we used insulin and took out a series of in vitro investigations on these nanoparticles.METHODS: Size-exclusive chromatography was used to separate freeand encapsulated insulin molecules.Insulin concentration was measured by radioimmunoassay (RIA).Insulin associated to nanoparticles was digested by trypsin.125I-insulin nanoparticles were dissolved by acetonitrile and radioactivity distribution was measured by γ-Counter.An “antibody-capture”procedure was devised.RESULTS: Most insulin (80%) was associated with nanoparticles. This was not due to adsorption,but through tight conjunction. Although the encapsulated insulin was on the surface of the nanoparticles,it could be measured by RIA and was partially resistant to trypsin degradation.When nanoparticles were dissolved,most of the insulin was not free in the solution,but was associated with the dissolved polymer.Finally,we used anti-insulin antibody to react with the encapsulated insulin,and this led to capture of the nanoparticles as well,which could be detected by scanning electron microscope (SEM).CONCLUSION: Our results strongly suggested that the insulin was on the surface Of PACA nanoparticles,possibly through covalent bond to the polymer.