Synthesis, Characterization, and Drug Release Behaviour of Novel Soy Protein/Poly(acrylic acid) IPN Hydrogels

Aseries of novel interpenetrating polymer network (IPN) hydrogels based on soy protein (SP) and poly(acrylic acid) (PAA) were prepared with glutaraldehyde and N,N -methylenebisacrylamide (BIS) as the cross-linking agents. The structure and properties of the IPN hydrogels were characterized by FTIR, SEM, and DSC. The effects of pH and SP and BIS contents on the behaviour and release mechanism of the model drug bovine serum albumin (BSA) were also investigated in detail. The FTIR data indicated that the absorption of BSA into the IPN hydrogels is purely physical process. The SEM showed that changing the content of SP or BIS can influence the pore size and pore wall thickness of the hydrogels. The DSC data signify that all the hydrogels had good compatibility and miscibility, as well. It was also found that the release profiles of BSA strongly are dependent on the value of pH. The release percentage of BSA decreased with increasing the contents of SP or BIS. The BSA release profile followed Fickian diffusion pattern at pH below the pKa of PAA and the non- Fickian diffusion at pH above the pKa of PAA. The results showed that the IPN hydrogels are suitable candidates for colon drug delivery.