Development of efficient packaging method of oxygen sensitive drug by nano-crystalline powder coating

众所周知，由于聚合物主链的断裂，聚合物的机械分解会产生机械诱导的自由基，即所谓的机械自由基。在大多数聚合物中，机械活性物质在暴露在空气中后立即与氧气反应生成过氧基，过氧基的强度通常降低到原始碳心自由基的10%以下。然而，在肌醇存在下，通过机械操作得到的聚甲基丙烯酸机械棒在室温下非常稳定。从详细的分析结果可以看出，在聚合物粉末表面构建了由纳米肌醇颗粒组成的扩散阻挡层，阻止了氧的扩散。这些结果不仅有助于加深我们对分子间相互作用本质的理解，而且也为新型干法涂层的开发提供了基础信息。

It has been long known that mechanolysis of polymers gives rise to mechanically induced radicals, so-called mechanoradicals, due to the polymer main-chain scission. In most polymers, the mechanoradicals reacts with oxygen to form a peroxyl radicals immediately after exposure to air, and the intensity of peroxy radicals usually decreases to less than 10% of the original carbon-centered radicals. However mechanoradicals of polymethacrylic acid induced by mechanical operations in the presence of inositol were extremely stable for a long period of time at room temperature. From the results of the detailed analysis, it was found that diffusion barrier layer consisted of nano-sized inositol particles was constructed on the surface of polymer powder and prevented oxygen diffusion. The present results not only cotribute to enhancing our understanding of the nature of the intermolecular interaction, but also provide fundamental information for development of novel dry coating method.