Corn fiber gum-soybean protein isolate double network hydrogel as oral delivery vehicles for thermosensitive bioactive compounds

Corn fiber gum (CFG)-soybean protein isolate (SPI) double network (DN) hydrogels, with varied concentrations of CFG, were fabricated at room temperature in order to develop a biocompatible vehicle for the oral administration of thermosensitive bioactive compounds. Riboflavin (vitamin B-2) was encapsulated in the gel as a model bioactive compound. The compound release properties of these DN hydrogels were investigated in simulated gastric and simulated intestinal fluids (SGF and SIF). DN hydrogels with 0.25% of CFG were found to be the most desirable of those assayed for the oral administration of bioactive compounds. The results of low-field nuclear magnetic resonance (LF-NMR) relaxometry measurement showed that the pH-responsive DN hydrogels exhibited low swelling ratio in the SGF but larger swelling ratio in the SIF. The results of degree of proteolysis and scanning electron microscopy (SEM) showed that significant release of riboflavin from DN hydrogels in the SIF was due to large swelling, CFG matrix erosion and the proteolysis of SPI. The release mechanisms of riboflavin through the DN hydrogels in the simulated intestinal fluid followed non-Fickian diffusion based on Peppas' semi-empirical equation.