Guo Kai, Chu C C
Fiber and Polymer Science Program, Department of Fiber Science and Apparel Design, and Biomedical Engineering Program, Cornell University, Ithaca, New York 14853-4401.
J Biomed Mater Res B Appl Biomater. 2009 May;89(2):491-500. doi: 10.1002/jbm.b.31239.
Novel biodegradable submicron microspheres of amino acid based poly(ester amide)s (PEAs) were fabricated by an oil-in-water (O/W) emulsion/solvent evaporation technique and their morphology and drug loading efficiency were examined. PEAs microspheres of mean diameter <1 microm with very narrow size distribution were obtained at a fair yield about 80%. The effects of PEA polymer concentration, polyvinyl alcohol emulsifier concentration, and the homogenizer speed on the size and morphology of final PEA microspheres were examined by analyzing their SEM images. It is found that a low PEA concentration, a high PVA concentration, and a high homogenizer speed are the optimal conditions for obtaining smaller microspheres. The biodegradation behaviors of these PEA microspheres at 37 degrees C were investigated as a function of enzyme (alpha-chymotrypsin) concentration and incubation time. The data showed similar surface erosion degradation mechanism as PEA polymers reported previously. Paclitaxel loaded PEA microspheres with high encapsulation efficiency were obtained without significantly affecting their size and surface morphology. The high drug loading efficiency close to 100% suggested that PEA microspheres may have the potential for the injection administration of highly hydrophobic anticancer drugs.
通过水包油（O/W）乳液/溶剂蒸发技术制备了基于氨基酸的聚（酯酰胺）（PEA）新型可生物降解亚微米微球，并对其形态和载药效率进行了研究。以约80%的可观产率获得了平均直径<1微米且尺寸分布非常窄的PEA微球。通过分析扫描电子显微镜（SEM）图像，研究了PEA聚合物浓度、聚乙烯醇乳化剂浓度和匀化器速度对最终PEA微球尺寸和形态的影响。发现低PEA浓度、高聚乙烯醇（PVA）浓度和高匀化器速度是获得较小微球的最佳条件。研究了这些PEA微球在37℃下作为酶（α-胰凝乳蛋白酶）浓度和孵育时间函数的生物降解行为。数据显示出与先前报道的PEA聚合物相似的表面侵蚀降解机制。获得了具有高包封效率的载紫杉醇PEA微球，且未显著影响其尺寸和表面形态。接近100%的高载药效率表明PEA微球可能具有注射给药高疏水性抗癌药物的潜力。
