Qiu Wei, Ma Guang-Hui, Meng Fan-Tao, Su Zhi-Guo
National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, the Chinese Academy of Sciences, PO Box 353, Beijing 100080, China.
Sheng Wu Gong Cheng Xue Bao. 2004 Mar;20(2):245-51.
Methoxypoly (ethylene glycol)- block-poly (DL-lactide) (PELA) microcapsules containing bovine hemoglobin (BHb) were prepared by a W/O/W double emulsion-solvent diffusion process. The P50 and Hill coeffcient were 3466 Pa and 2.4 respectively, which were near to the natural bioactivity of bovine hemoglobin. The results suggested that polymer composition had significant influence on encapsulation efficiency and particle size of microcapsules. The encapsulation efficiency could reach 90% and the particle size 3 - 5 microm when the PELA copolymer containing MPEG 2000 block was used. The encapsulation efficiency and particle size increased with the concentration of PELA. Increasing the concentrations of NaCl in outer aqueous solution resulted in the increase of encapsulation efficiency and the decrease of particle size. As the concentration of stabilizer in outer aqueous solution increased in the range of 10 g/L to 20 g/L, the particle size reduced while encapsulation efficiency was increased, further increase of the stabilizer concentration would decrease encapsulation efficiency. Increasing of primary emulsion stirring rate was advantageous to the improvement of encapsulation efficiency though it had little influence on the particle size. The influence of re-emulsion stirring rate was complicated, which was not apparent in the case of large volume of re-emulsion solution. When the wall polymer and primary emulsion stirring rate were fixed, the encapsulation efficiency decreased as the particle size reduced.
采用W/O/W双乳液-溶剂扩散法制备了包载牛血红蛋白（BHb）的甲氧基聚（乙二醇）-嵌段-聚（DL-丙交酯）（PELA）微胶囊。其P50和希尔系数分别为3466 Pa和2.4，接近牛血红蛋白的天然生物活性。结果表明，聚合物组成对微胶囊的包封率和粒径有显著影响。当使用含有MPEG 2000嵌段的PELA共聚物时，包封率可达90%，粒径为3 - 5微米。包封率和粒径随PELA浓度的增加而增大。增加外部水溶液中NaCl的浓度会导致包封率增加和粒径减小。当外部水溶液中稳定剂浓度在10 g/L至20 g/L范围内增加时，粒径减小而包封率增加，稳定剂浓度进一步增加会降低包封率。提高初乳搅拌速率有利于提高包封率，尽管对粒径影响不大。复乳搅拌速率的影响较为复杂，在复乳溶液体积较大的情况下不明显。当壁材聚合物和初乳搅拌速率固定时，包封率随粒径减小而降低。
