Starch-based biodegradable hydrogels with potential biomedical applications as drug delivery systems

The design and preparation of novel biodegradable hydrogels developed by the free radical polymerization of acrylamide and acrylic acid, and some formulations with bis-acrylamide, in the presence of a corn starch/ethylene-co-vinyl alcohol copolymer blend (SEVA-C), is reported. The redox system benzoyl peroxide (BPO) and 4-dimethylaminobenzyl alcohol (DMOH) initiated the polymerization at room temperature. Xerogels were characterized by H-1 NMR and FTIR spectroscopies. Swelling studies were performed as a function of pH in different buffer solutions determining the water-transport mechanism that governs the swelling behaviour. Degradation studies of the hydrogels were performed in simulated physiological solutions for time up to 90 days, determining the respective weight loss, and analyzing the solution residue by H-1 NMR. The mechanical properties of the xerogels were characterized by tensile and compressive tests, as well as by dynamo-mechanical analysis (DMA). Dynamo-mechanical parameters are also reported for hydrated samples. (C) 2002 Elsevier Science Ltd. All rights reserved.