PLGA-藻酸盐核-壳微球的制备表征及药物控释的应用

香港大学李嘉诚医学院骨科与外伤学系的Michael Kai Tsun To教授团队，取得了以下成果。首先使用毛细管微流体装置制造具有受控尺寸和均匀壳层的单分散PLGA-藻酸盐核–壳微球，以控制药物释放动力学。通过微流体装置的几何形状和流体流速很容易控制PLGA核心的尺寸。制作尺寸为15~50μm的PLGA微球，以研究核心尺寸对释放动力学的影响。将利福平装载到单分散PLGA微球和PLGA-藻酸盐核–壳微球中作为释放动力学研究的模型药物。利福平的体外释放显示，所有大小的PLGA核心均呈现S形释放模式，尽管较小的PLGA核心具有更高的释放速率和更短的滞后期。壳作为缓冲层可以调节药物释放动力学，当PLGA核心的药物释放速率足够高时，能够观察到接近零级的释放模式。通过MTT法对L929小鼠成纤维细胞细胞系进行PLGA-藻酸盐核–壳微球的生物相容性检测，结果显示无明显细胞毒作用。该技术提供了一种简便的方法，通过精细控制微结构来控制PLGA微球的药物释放动力学。所获得的单分散PLGA-藻酸盐核–壳微球具有单分散的粒径和均匀的壳层，是一种很有前景的装置，用于控制药物释放。

Recently, Michael Kai Tsun To who working in the Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, made the following outcome. Monodisperse PLGA–alginate core–shell microspheres with controlled size and homogeneous shells were first fabricated using capillary microfluidic devices for the purpose of controlling drug release kinetics. Sizes of PLGA cores were readily controlled by the geometries of microfluidic devices and the fluid flow rates. PLGA microspheres with sizes ranging from 15 to 50μm were fabricated to investigate the influence of the core size on the release kinetics. Rifampicin was loaded into both monodisperse PLGA microspheres and PLGA–alginate core–shell microspheres as a model drug for the release kinetics studies. The in vitro release of rifampicin showed that the PLGA core of all sizes exhibited sigmoid release patterns, although smaller PLGA cores had a higher release rate and a shorter lag phase. The shell could modulate the drug release kinetics as a buffer layer and a near-zero-order release pattern was observed when the drug release rate of the PLGA core was high enough. The biocompatibility of PLGA–alginate core–shell microspheres was assessed by MTT assay on L929 mouse fibroblasts cell line and no obvious cytotoxicity was found. This technique provides a convenient method to control the drug release kinetics of the PLGA microsphere by delicately controlling the microstructures. The obtained monodisperse PLGA–alginate core–shell microspheres with monodisperse size and homogeneous shells could be a promising device for controlled drug release.

（丛政）

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