Morphology, drug distribution, and in vitro release profiles of biodegradable polymeric microspheres containing protein fabricated by double-emulsion solvent extraction/evaporation method
Morphology, drug distribution, and in vitro release profiles of biodegradable polymeric microspheres containing protein fabricated by double-emulsion solvent extraction/evaporation method
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DOI：
10.1016/s0142-9612(00)00178-2
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发表时间：
2001-02-01
期刊：
影响因子：
14
通讯作者：
Ng, NP
中科院分区：
文献类型：
--
作者：
Yang, YY;Chung, TS;Ng, NP
本文研究了含BSA（牛血清白蛋白）的聚己内酯（PCL）和聚乳酸-共乙醇酸（PLGA） 65:35微球的表面和内部形态、22℃下药物分布和释放动力学，以期了解其形态、药物分布和体外释放特性之间的关系，并为热带地区海洋鱼类的控释装置的开发提供依据。CLSM（共聚焦激光扫描显微镜）显微照片显示，聚乙烯醇（PVA作为乳化剂）在外部水相中的浓度强烈影响药物在微球内的分布和释放曲线。内部水相中PVA的存在增强了内部水滴的抗聚结稳定性。这导致更均匀的药物分布和较慢的BSA释放。不同的油相体积和聚合物浓度会产生不同的溶剂交换和沉淀机制，从而导致不同的形貌。低油相体积产生具有多孔基质和缺陷皮肤表面的微球，这提供了高初始BSA爆发和快速释放轮廓。由低聚合物浓度制备的微球具有较少缺陷的皮肤表面，但具有较少弯曲的内部基质，从而导致更快的BSA释放。BSA负载越高，乳状液滴与连续水相之间以及微球与体外培养基之间的浓度梯度越大。前者导致较低的封装效率，而后者产生更快的初始爆发和更快速的释放轮廓。高搅拌速度可以减小微球尺寸，但会降低微球的收率。(C) 2000 Elsevier Science Ltd.版权所有。
The surface and internal morphology, drug distribution and release kinetics at 22 degreesC of polyesters such as PCL (polycaprolactone) and PLGA (poly(DL-lactic-co-glycolic acid)) 65:35 microspheres containing BSA (bovine serum albumin) have been investigated in order to understand the relationship amongst morphology, drug distribution and in vitro release profiles and to develop controlled release devices for marine fishes in tropical area. CLSM (confocal laser scanning microscope) micrographs reveal that the polyvinylalcohol (PVA as an emulsifier) concentration in the external water phase strongly influences drug distribution within microspheres and release profiles. The presence of PVA in the internal water phase enhances the stabilization of inner water droplets against coalescence. This results in a more uniform drug distribution and a slower BSA release. Different oil-phase volumes and polymer concentrations yield different solvent exchange and precipitation mechanisms, which lead to different morphologies. A low oil-phase volume yields microspheres with a porous matrix and defective skin surface, which gives a high initial BSA burst as well as a fast release profile. Microspheres fabricated from a low polymer concentration have less defective skin surface, but with a less tortuous inner matrix which results in a more rapid BSA release. A higher BSA loading yields a larger concentration gradient between the emulsion droplet and the continuous water phase as well as between the microspheres and the in vitro medium. The former results in a lower encapsulation efficiency, whereas the latter yields a faster initial burst and a more rapid release profile. High stirring speed can reduce microsphere size, but decreases the yield of microspheres. (C) 2000 Elsevier Science Ltd. All rights reserved.