重组人骨形态发生蛋白2缓释微球的制备与评价

目的：针对重组入骨形态发生蛋白2（recombinant human bone morphogenetic protein-2，rhBMP-2）在体内半衰期短、易被稀释代谢的问题，探讨利用聚乳酸-羟基乙酸共聚物（PLGA）制备载rhBMP-2微球的可行性和制备工艺，并观察其载药、释药特性。方法：①采用W／O／W型复乳化-溶剂挥发技术制备rhBMP-2／PLGA缓释微球，并对微球的粒径和形态、包封率和载药量，体外释放性质进行测定。②异位成骨实验：昆明小鼠12只，在右侧大腿股内侧肌袋内植入含rhBMP-2的50mgPLGA微球，4周后取材，观察成骨情况以初步检测微球中的蛋白质活性。结果：①rhBMP-2／PLGA缓释微球形态良好，粒径主要集中在50—60μm，包封率为（37．52±4．31）％，载药率为（5．12±1．32）％。②微球的释放存在突释，7d内释放的药物量超过40％，大约90％的药物量于42d内释放完全。③载药微球植入鼠股部肌袋4周，材料周围有明显的骨形成。结论制备的rhBMP-2／PLGA微球可以缓慢释放有活性的rhBMP-2，具有临床应用的可行性。

Preparation and evaluation of recombinant human bone morphogenetic protein-2 loaded microsphere

AIM： Recombinant human bone morphogenetic protein-2 （rhBMP-2） is prone to dilute and conduct metabolism, with a short half-life period in vivo. This study investigated the feasibility and the preparation of rhBMP-2 carrying poly （lactic-co-glycolide） （PLGA）, and observed drug-loading and drug-releasing function. METHODS： 1.The rhBMP-2/PLGA microspheres were prepared using W/O/W solvent evaporation method. The particle size and morphology of the microspheres, the drug loading, the efficiency of encapsulation and in vitro release behaviors were detected.2. PLGA microspheres containing 50 mg rhBMP-2 were implanted into medial vastus muscle pouches of right lateral thigh in 12 Kunming mice, and the ectopic bone formation and the activity of rhBMP-2 released from the mierospheres were evaluated 4 weeks later by the heterotopia bone formation experiment.RESULTS： 1.The rhBMP-2/PLGA mierospheres showed good morphology with the particles diameter at 50-60 μm, the envelopment ratio （37.52±4.31 ）%, and the ratio of drug loading （5.12±1.32）%.2.Initial burst release of the mierospheres occurred, the drug release exeended 40% within 7 days, and approximately 90% of the drugs was released within 42 days.3.Fonr weeks after the rhBMP-2/PLGA implanted into muscle pouches of mice, obvious bone formation was detectable histologically. CONCLUSION： The rhBMP-2/PLGA mierospheres can release slowly active rhBMP-2, showing a potential clinical application.