Dynamics of antimicrobial hydrogels in physiological saline

It is critical in the design of hydrogel drug release system to understand the effect of drugs on the properties of hydrogel. Physically cross-linked hydrogels – pea starch (PS) gel formed by hydrogen bonding and calcium alginate (ALG) gel by ionic interaction were investigated in this paper. Antimicrobials added in the starch gel and alginate gel were trisodium phosphate (TSP) and acidified sodium chlorite (ASC), respectively. Solids loss, water uptake, antimicrobial release, and change in storage modulus for both blank and antimicrobial hydrogels immersed in a saline solution were evaluated as a function of time. The apparent diffusivities of total solids, water and antimicrobials in hydrogel were determined according to Fickian diffusion. It was found that TSP in PS gel simultaneously accelerated the loss of total solids and uptake of water in the hydrogel, entailing an increased reduction in the total solid content. Consequently, the storage modulus of the antimicrobial PS gel decreased faster than the blank PS gel. The diffusivities of antimicrobials, 2.72 × 10−9 m2 s−1 for TSP in PS gel and 6.58 × 10−9 m2 s−1 for ASC in alginate gel, were close to those of water but much lower than those of total solids, suggesting that gel swelling control the release of antimicrobials. Controlled antimicrobial release systems based on hydrogel are expected to see applications in preserving fresh carcass in the meat and poultry industries.