生长因子PLGA微包囊成形参数的实验研究

An Experimental Study to Optimize the Parameters of Growth Factors PLGA Microsphere

目的:优化骨组织工程研究中生长因子微包囊的制作参数,观察其释放规律,为更有效的利用生长因子的生物活性提供依据。方法:通过正交实验设计方法设计27组试验,采用不同组合因变量为制作参数,制作PLGA微包囊,检测相应情况下微包囊的包封率和粒径大小,制作多元回归方程。将包裹有BSA的PLGA微包囊置于恒温震荡培养箱震荡进行体外缓释试验研究。结果:各优化变量对微包囊的粒径及其包封率均有影响,包囊表面光滑,成球较好。体外能够在11天内缓慢释放。结论:正交试验设计优化PLGA微包囊制备的各项参数,回归方程对试验结果可较好的进行预测,PLGOA微包囊在体外能够长时间缓释。

Background GF （growth factors） is a sort of important materials that can control cell growth, induce cell multiplication, keep cytoactivity, etc. They play a key role in bone growth and repair. But short biological half-life leads GF not to produce a marked effect in vivo. So how to maintain the bioactivity of GF restricts practical application of them. Objective To optimize the preparation of PLGA microsphere and investigate their produced method, general properties and drug release characteristics in vitro. Methods： BSA loaded PLGA microsphere were place into shake culture box to observe the degradation and release characteristics of PLGA microsphere in vitro. Samples were taken to test cumulative release amount according to the BSA standard curve in normal saline at 2,4,8,12,24,36,48,60,72,84,96 h,5,6,7,8,9,10.11d. Twenty seven experiments were designed to optimize PLGA microsphere production processed by using orthogonal design with combinations of varying effective factors which impact the encapsulation efficiency and the diameter of PLGA microsphere. Size distribution and encapsulation efficiency of the microsphere were two major outcome measures of this study. Encapsulation efficiency was calculated according to the formula, which was the ratio between actual drug loading rate and theory drug loading rate. Every test sample was used to collect pictures under light microscope. Diameter of 100 microsphere was measured on these pictures by Image-Pro plus 5.1 after adjusted scale of this software every time. All the data were entered to SPSS 12.0 to process the correlation within parameters of diameter or encapsulation efficiency. Results： PLGA microsphere had smooth surface and uniform body. Generally, the diameter of microsphere was about 100-150 micrometer. The BSA was encapsulated into PLGA microsphere and could be slowly released in two stages within 11 days. Conclusions： PLGA microsphere could be used as a good slow release carrier. The preparation of PLGA microsphere was optimized by orthogonal design. In a certain extent, the results of the experiments could predict the characteristics of PLGA microsphere.