EPLA/nHAp composite microsphere, a novel drug delivery system potentially useful for the local delivery of alendronate (AL) to bone tissue was developed via the biomimetic mineralized deposition of nano-hydroxyapatite (nHAp) crystals on the surface of aminated modified polylactic acid (EPLA) microspheres. Scanning electron microscopy (SEM) observation showed that this system consisted of a polymer core with nanofiber network structure and inorganic coating composed of countless rod-like nanocrystalline particles, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) confirmed that these particles were nHAp crystals. An efficient AL-loading can be realized by facile impregnation-adsorption method under suitable conditions due to the high adsorption capacity of EPLA/nHAp composite microspheres. The drug loading efficiency of microspheres was detected by indirect ultraviolet spectrophotometry. It was found that the adsorption capacity of EPLA/nHAp composite microsphere towards AL was increased nearly 5-fold compared with that of bare EPLA microspheres owing to the strong interaction between alendronate and hydroxyapatite. Meanwhile, in vitro release study showed that AL-loaded EPLA/nHAp microspheres had a more sustained drug release than AL-loaded EPLA microspheres, all these results demonstrated that the as-prepared EPLA/nHAp composite microsphere is an efficient carrier for the delivery and sustained release of AL. Furthermore, an in vitro cell culture study revealed that these composite microspheres presented a good biocompatibility, showing great potential for the applications in the biomedical field.

EPLA / nHAp复合微球是通过在胺化改性聚乳酸​​（EPLA）表面上纳米羟基磷灰石（nHAp）晶体的仿生矿化沉积而开发的，对潜在的将阿仑膦酸盐（AL）局部递送至骨组织有用的新型药物递送系统）微球。扫描电子显微镜（SEM）观察表明，该系统由具有纳米纤维网络结构的聚合物核和由无数个棒状纳米晶体颗粒组成的无机涂层组成，傅立叶变换红外光谱（FTIR）和X射线衍射分析（XRD）证实了这些颗粒是nHAp晶体。由于EPLA / nHAp复合微球的高吸附能力，可以在合适的条件下通过简便的浸渍-吸附方法实现有效的铝负载。通过间接紫外分光光度法检测微球的载药效率。结果发现，由于阿仑膦酸盐和羟基磷灰石之间的强相互作用，EPLA / nHAp复合微球对铝的吸附能力比裸露的EPLA微球增加了近5倍。同时，体外释放研究表明，载有AL的EPLA / nHAp微球比载有AL的EPLA微球具有更持久的药物释放，所有这些结果表明，所制备的EPLA / nHAp复合微球是递送和递送的有效载体。持续释放AL。此外，一项体外细胞培养研究表明，这些复合微球具有良好的生物相容性，在生物医学领域具有广阔的应用前景。