Mongia N K, Anseth K S, Peppas N A
Biomaterials Laboratory, School of Chemical Engineering, Purdue University, West Lafayette, IN 47907-1283, USA.
J Biomater Sci Polym Ed. 1996;7(12):1055-64. doi: 10.1163/156856296x00543.
Ultrapure poly(vinyl alcohol) (PVA) hydrogels were prepared by exposing an aqueous solution of 15 or 20 wt% PVA to repeated cycles of freezing for 6 or 12 h at -20 degrees C and thawing for 2 hours at 25 degrees C. The adhesive characteristics of the PVA gels in contact with a reconstituted mucus surface were quantified using a tensile technique. As the number of freezing/thawing cycles increased, the work of fracture (adhesion) decreased due to the increase in the PVA degree of crystallinity. Crystallinity was determined using differential scanning calorimetry. PVA gels prepared from the 20 wt% solution and exposed to two cycles of freezing/thawing exhibited the largest work of adhesion. Drug delivery studies were conducted with ketanserin, a wound healing enhancer. Release studies were conducted using PVA samples prepared from a 20-wt% solution that were exposed to two or three freezing cycles for 12 h followed by thawing for 2 h. Results from the release of the drug from the PVA sample exposed to two cycles showed that approximately 80% of the ketanserin was released within 4 h.
通过将15%或20%（重量）的聚乙烯醇（PVA）水溶液在-20℃下反复冷冻6或12小时，然后在25℃下解冻2小时，制备了超纯聚乙烯醇（PVA）水凝胶。使用拉伸技术对PVA凝胶与重构黏液表面接触时的黏附特性进行了量化。随着冻融循环次数的增加，由于PVA结晶度的提高，断裂功（黏附力）降低。使用差示扫描量热法测定结晶度。由20%（重量）溶液制备并经历两个冻融循环的PVA凝胶表现出最大的黏附功。使用酮色林（一种伤口愈合增强剂）进行了药物递送研究。使用由20%（重量）溶液制备的PVA样品进行释放研究，这些样品经过两个或三个12小时的冷冻循环，然后解冻2小时。来自经历两个循环的PVA样品的药物释放结果表明，约80%的酮色林在4小时内释放。
