Yu Lan, Zhang Hua, Cheng Si-Xue, Zhuo Ren-Xi, Li Hua
Key Laboratory of Biomedical Polymers of Ministry of Education, Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
J Biomed Mater Res B Appl Biomater. 2006 Apr;77(1):39-46. doi: 10.1002/jbm.b.30395.
End-functionalized poly/oligo(epsilon-caprolactone)s were synthesized through the ring-opening polymerization of epsilon-caprolactone initiated by cholesterol with a hydroxyl group. Using the end-functionalized poly/oligo(epsilon-caprolactone)s with different molecular weights, the microsphere drug delivery systems were fabricated using a convenient melting-emulsion method. The drug release properties of microspheres were investigated with the presence of an enzyme, Pseudomonas cepacia lipase, as well as in the absence of the enzyme. The release profiles can be fitted nicely by the classical empirical exponential expression. Under the hydrolytic condition, the drug release is mainly controlled by Fickian diffusion, and the high molecular weight of the matrix results in a slower drug release rate. Under the enzymatic condition, the drug release is dominated by combined degradation and diffusion mechanism, and the high molecular weight sample exhibits a faster release rate that is mainly caused by the higher degradation rate of the sample with lower cholesteryl moiety content.
通过胆固醇上的羟基引发ε-己内酯的开环聚合反应，合成了端基功能化的聚/低聚（ε-己内酯）。使用具有不同分子量的端基功能化聚/低聚（ε-己内酯），通过简便的熔融乳化法制备了微球药物递送系统。研究了在洋葱伯克霍尔德氏菌脂肪酶存在和不存在的情况下微球的药物释放特性。释放曲线可以很好地用经典经验指数表达式拟合。在水解条件下，药物释放主要受菲克扩散控制，基质的高分子量导致药物释放速率较慢。在酶促条件下，药物释放由降解和扩散联合机制主导，高分子量样品表现出更快的释放速率，这主要是由于胆固醇部分含量较低的样品降解速率较高所致。
