Unveiling the swelling behavior of κ-carrageenan hydrogels: Influence of composition and physiological environment on drug delivery potential

This study aims to develop a biodegradable hydrogel wound dressing film based on carrageenan and agar loaded with tetracycline (TC), which exhibits high antibacterial properties and accelerates wound healing. The swelling behavior of κ-carrageenan/agar and tetracycline-loaded hydrogel films was examined, with a focus on the hydrogel’s efficacy in various physiological fluids, as well as the effects of polysaccharide ratio, cross-linker concentration, and surfactant concentration. The results revealed that the polysaccharide ratio significantly influenced the hydrogel swelling capacity of hydrogel, and a 1:1 ratio of agar to κ-carrageenan achieved the highest swelling degree of 1386 %. Addition of KCl, as a cross-linker, increased swelling capacity to 1713 %. Furthermore, surfactant concentration also influenced swelling behavior, and higher concentrations resulted in an increase in hydrophilicity and swelling. Hydrogel swelling performance varied across physiological fluids, with the highest and lowest swellings observed in deionized water (DIW) and simulated wound fluid (SWF), respectively. The swelling process in DIW and phosphate buffered saline (PBS) exhibited second-order kinetics, whereas non-Fickian diffusion mechanisms were observed in SWF. The drug release of the κC/AG/TC hydrogel film was controlled by its swelling capacity and the pH of medium. The hydrogels’ mechanical properties, antibacterial activity, and water vapor permeability were also investigated.