缓释bFGF-PLGA微球制备及其体外释药性质和生活活性的研究

 目的 制备bFGF-PLGA微球，考察其一般性质、体外释药特性和微球中bFGF生物活性保存情况。方法 应用复乳干燥法制备缓释bFGF-PLGA微球(bFGF-PLGA-Ms)，并考察其一般性质。采用ELISA法建立用于bFGF含量测定的标准方法和回归方程，模拟体内条件研究微球体外释药特性。将bFGF-PLGA-Ms加入成纤维细胞培养液中，MTT法观察细胞增殖情况。结果 微球表面光滑圆整，球体均匀度好，平均粒径为(1.552±0.015)μm，冻干粉剂为白色粉末状，再分散性良好，临界相对湿度为64%，CH₂Cl₂残留量低于限量的1/10，微球包封率和载药量分别为(66.43±1.24)%和［(27.18±0.51)×10^-3］%。微球体外释药规律符合Higuichi方程：Q=25.884 6t_1/2-15.705 1(r=0.997 5)，突释期内释放度仅为19.26%，11 d后其释放度达到72.47%。培养初期，bFGF组A值高于其余两组；培养中后期，PLGA微球组A值高于其余两组，差异均有显著性意义（q检验，P<0.05）。结论 bFGF-PLGA微球及其冻干粉剂制备工艺良好；微球中bFGF生物活性保存良好，体外具有明显缓释作用。

Preparation of bFGF-PLGA sustained release microspheres and studies on their release characteristics and biologic activity in vitro

OBJECTIVE To prepare bFGF-PLGA microspheres (bFGF-PLGA -Ms) and investigate their general properties, in vitro drug release characteristics and biologic activity of bFGF released from the microspheres METHODS The bFGF-PLGA microspheres were prepared by w/o/w multiple emulsion volatilizing method. Their general properties were observed. To measure the content of bFGF, ELISA method was used and the regression equation was established. The bFGF-PLGA -Ms were kept in 0.9% sodium chloride solution to study their in vitro release characteristics. The proliferation of the cultured fibroblast was measured with MTT method after bFGF-PLGA-Ms being added to the DMEM culture medium RESULTS The bFGF-PLGA-Ms were good, even and uniform spheres with mean particle size of (1.552±0.015)μm. The lyophilized powder was pure white with good dispority. Its critical humidity was 64%. The content of CH₂Cl₂ was less than 1/10 of the limited value. The drug loading amount and encapsulation efficiency of bFGF-PLGA-Ms were ［(27.18±0.51)×10^-3］% and (66.43±1.24)% respectively. The in vitro release profile of bFGF-PLGA -Ms was figured by Higuichi equation:Q=25.884 6t^1/2-15.705 1(r=0.997?5). The drug release rate was only 19.26% during the burst release phase and rose to 72.47% at the 11th day. 2 and 3 days after plate culturing， the absorption values at 490 nm of bFGF group were much higher than those of the bFGF-PLGA-Ms group and the PLGA group; 4 to 6 days after plate culturing， the A values of bFGF-PLGA-Ms group was the highest among the three groups CONCLUSION The bFGF-PLGA-Ms and their lyophilized powder have excellent pharmaceutical properties showing sustained release effect in vitro with good biological activity.