A sustained release system that composed of biodegradable core-sheath nanofibers in 3D hierarchy has been developed through electrospinning of water-in-oil precursor emulsion, in which theophylline dissolved in water was labeled as ‘aqueous phase’ and PLA solution was considered as ‘organic phase’. SEM images revealed that the fibers crossed and overlapped with each other, forming a 3D network-like structure. TEM indicated that the drug was well incorporated into PLA nanofibers, forming a core-sheath structure, which represented a reservoir-type delivery system. The fiber scaffolds were further characterized by FTIR, XRD, TGA, and DSC, which proved theophylline was successfully loaded into the fibers in an amorphous form. The release of drug consisted of three sequential stages, in which the release rate decreased successively. The changes on release rate were proved to be related to the drug diffusion and polymer degradation. At nearly 30 days, the drug still released continuously. This was accomplished by the gradually swelling and degradation of PLA. The successful preparation of the 3D core-sheath nanofibers can incorporate a water-soluble drug in a biodegradable polymer, which effectively protected the activity of the drug, inhibited a sudden release and accomplished sustained release.

中文翻译：

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通过乳液静电纺丝制备的可生物降解的核-鞘纳米纤维 3D 层次结构用于缓释药物

通过电纺油包水前体乳液，开发了一种由 3D 层次结构中可生物降解的核-鞘纳米纤维组成的缓释系统，其中溶解在水中的茶碱被标记为“水相”，PLA 溶液被认为是“有机相”。阶段'。SEM 图像显示纤维相互交叉重叠，形成 3D 网络状结构。TEM 表明该药物很好地结合到 PLA 纳米纤维中，形成了核-鞘结构，代表了一种储库型递送系统。纤维支架通过 FTIR、XRD、TGA 和 DSC 进一步表征，证明茶碱以无定形形式成功加载到纤维中。药物的释放由三个连续的阶段组成，其中释放速率依次降低。释放速率的变化被证明与药物扩散和聚合物降解有关。近30天，药物仍持续释放。这是通过 PLA 的逐渐溶胀和降解来实现的。3D核鞘纳米纤维的成功制备可以将水溶性药物掺入可生物降解的聚合物中，有效保护药物的活性，抑制突然释放并实现缓释。