乳酸-羟基乙酸共聚物缓释微球的制备、性能及应用

用于制备乳酸-羟基乙酸共聚物缓释微球的方法很多，可根据聚合物和药物的性质进行选择，其中乳化-固化法是目前制备乳酸-羟基乙酸共聚物缓释微球中最常用的方法，适用于在连续相中不溶或难溶的药物，缺点在于使用有机溶剂，不利于保持药物的活性，复乳化时工艺也比较复杂，不适宜进行工业化生产；喷雾干燥技术是一种快速的一步微囊化过程，其条件温和，制得的微球具有粒度分布窄、包封率高等特点，其用于不稳定药物微囊化的大规模生产极具潜力。由于给药初期的突释有可能导致血药浓度接近或超过中毒水平，产生明显的毒副作用。乳酸-羟基乙酸共聚物的分子质量、乳酸-羟基乙酸共聚物的纯度、主药理化性质、微球制备方法及制备参数、微球载药量等均是影响突释程度的具体因素。目前防止突释或降低突释程度的方法主要有改变载体材料结构、适当的微球制备以及萃取、洗涤或加入附加剂等。乳酸-羟基乙酸共聚物微球控释系统具有延长药物释放时间、靶向释放、降低药物毒性和刺激性等特点，存在多种给药途径可肌肉注射、皮下注射、玻璃体内注射、关节腔内给药、植入给药、黏膜给药等。

Preparation, performance and application of poly (iactide-co-glycolide) microspheres

Emulsification-solidification method has been presently reported to be a common technique to prepare poly (iactide-co-glycolide) microspheres, beneficial for undissolved or indissolvable drugs in continuous phase but limited by not retaining activity due to addition of organic solvents and not performing in industrialized production due to complex multiple emulsification technique. Spray drying technique is a fast microencapsulation. In a gentle environment, the prepared microspheres were characterized by narrow particle size distribution and high enveloping rate, potential for a large-scale production of instable drug microencapsulation. In an early medication, blood drug level was closed to or over toxic level due to burst which could also cause toxic and side effects. Burst was affected by molecular mass, purity, major pharmacological property of poly (iactide-co-glycolide), preparation, parameter, and drug-carrying amount of microspheres. Presently, prevention or reduction of burst is performed based on structural changes of carrier materials, preparation, abstraction, and clearing of microspheres, and addition of supplemental agents. Controlled release system of poly (iactide-co-glycolide) microspheres can prolong time of drug release and target release and decrease toxicity and stimulation via intramuscular injection, subcutaneous injection, intravitreal injection, intra-articular cavity medicine, implantation medicine, and mucous membrane medicine.