无乳链球菌乳酸-羟基乙酸共聚物微球的制备及其体外释放特点分析

以乳酸-羟基乙酸共聚物（PLGA）为材料，采用复乳溶剂挥发法制备无乳链球菌（Streptococcus agalactiae）全菌及超声破碎后的上清微球疫苗。显微镜观察显示随着 PLGA 质量浓度、PVA（聚乙烯醇）质量浓度和外水相体积的增加，上清微球平均粒径均随之增大。最终确定上清微球制备条件为 PLGA 质量浓度25 mg·mL -1、PVA 质量浓度1 mg·mL -1、外水相体积20 mL。全菌微球制备条件与上述的相比，仅 PVA 质量浓度调整为2 mg·mL -1。扫描电镜观察显示全菌和上清微球平均粒径分别为9.4μm 和3.9μm，微球均呈球形。BCA（二喹啉甲酸）法分析显示包封率分别为68.07％和63.49％；载药量分别为5.49＆#215;108个·mg -1和3.58％；28 d 体外累积释放量分别为64.2％和82.8％。

Preparation of PLGA microparticles containing GBS and their release characteristics in vitro

We prepared polylactic-co-glyconlicacid（PLGA）microparticles containing Streptococcus agalactiae（Group B streptococcus, GBS）whole cell and supernatant after ultrasonication by double emulsion-solvent evaporation method. With increasing PLGA concentra-tion,emulsifier concentration and volume of outer water phase,the average diameter of microparticles containing supernatant increased. We used 25 mg·mL -1 of PLGA,1 mg·mL -1 of emulsifier concentration and 20 mL of outer water phase for preparation of microparticles containing supernatant. The preparation parameters were similar for GBS whole cell microparticles except that the emulsifier concentration was 2 mg·mL -1. The result by scanning electron microscope（SEM）shows that the average diameters of GBS whole cell and supernatant microparticles were 9. 4 μm and 3. 9 μm,respectively,and all the prepared microparticles were spherical in shape. The encapsulation efficiency of GBS whole cell and supernatant microparticles were 68. 07% and 63. 49%,respectively;the drug loading were 5. 49 ＆#215;108 ind·mg -1 and 3. 58% ,respectively;the cumulative rate of drug-release over 28 d were 64. 2% and 82. 8% ,respectively.