Shalaby W S, Park K
Purdue University, School of Pharmacy, West Lafayette, Indiana 47907.
Pharm Res. 1990 Aug;7(8):816-23. doi: 10.1023/a:1015956714669.
Albumin-cross-linked hydrogels were prepared by free radical polymerization using 1-vinyl-2-pyrrolidinone as a monomer and functionalized albumin as a crosslinking agent. The degree of chemical cross-linking was controlled by varying the degree of albumin functionality and the concentration of albumin. With emphasis placed on the potential use of these hydrogels for long-term oral drug delivery, gel characterization studies examined both the swelling and the mechanical properties in the absence and presence of pepsin. In the absence of pepsin, the equilibrium swelling ratio in simulated gastric fluid ranged from 17 to 55, depending on the degree of albumin functionality and the albumin concentration. Swelling was pH dependent at pH's greater than 7. The uptake of solvent into the dried hydrogels was determined to be Fickian. The integrity of swelling gels was dependent on the concentration of the functionalized albumin as well as on the degree of albumin functionality. In the presence of pepsin, a predominance of either surface or bulk degradation was observed, depending on the functionality of the albumin used as a cross-linker. Gel integrity during pepsin degradation also showed a marked dependence on the albumin functionality.
以1-乙烯基-2-吡咯烷酮为单体、功能化白蛋白为交联剂，通过自由基聚合制备了白蛋白交联水凝胶。通过改变白蛋白功能化程度和白蛋白浓度来控制化学交联程度。鉴于重点关注这些水凝胶在长期口服给药方面的潜在用途，凝胶特性研究考察了在有无胃蛋白酶存在的情况下的溶胀和机械性能。在没有胃蛋白酶的情况下，模拟胃液中的平衡溶胀率在17至55之间，这取决于白蛋白功能化程度和白蛋白浓度。在pH大于7时，溶胀依赖于pH值。确定干燥水凝胶对溶剂的吸收符合菲克定律。溶胀凝胶的完整性取决于功能化白蛋白的浓度以及白蛋白功能化程度。在有胃蛋白酶存在的情况下，根据用作交联剂的白蛋白的功能，观察到主要是表面降解或本体降解。胃蛋白酶降解过程中的凝胶完整性也显著依赖于白蛋白功能。
