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采用超声改性法制备改性淀粉,通过预聚-扩链-中和-分散法合成聚氨酯水溶液,并用相分离法制备出超声改性淀粉/聚氨酯复合微球。考察了R值[n(—NCO)/n(—OH)]、改性淀粉的含量、聚乙二醇的分子量及固含量对复合微球形态的影响。研究了载药复合微球在体外的药物释放规律。并通过扫描电子显微镜和傅里叶变换红外光谱对微球的表面及剖面结构和化学组成进行了表征。结果表明:复合微球合成的最佳条件:R值为3,改性淀粉含量为6%(wt,质量分数,下同),聚乙二醇分子量为200,固含量为38%;复合微球表面光滑并且内部有很多致密的孔道,且聚氨酯和改性淀粉之间通过氢键连接,稳定性良好;降解性及药物释放研究显示,该类微球适于充当药物载体。
The modified starch was prepared by ultrasonic modification and the aqueous polyurethane solution was prepared by prepolymerization - chain extension - neutralization - dispersion method. Ultrasound modified starch / polyurethane composite microspheres were prepared by phase separation. The effects of R value [n (-NCO) / n (-OH)], modified starch content, polyethylene glycol molecular weight and solid content on the morphology of the composite microspheres were investigated. The drug release characteristics of drug-loaded composite microspheres in vitro were studied. The surface and cross-sectional structure and chemical composition of the microspheres were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The results showed that the optimal conditions for the synthesis of composite microspheres were as follows: the R value was 3, the content of modified starch was 6% (wt, the same below), the molecular weight of polyethylene glycol was 200 and the solid content was 38% The surface of the sphere is smooth and has many dense pores inside, and the stability between the polyurethane and the modified starch is good by hydrogen bonding. Degradation and drug release studies have shown that these microspheres are suitable as drug carriers.