In this study, a hydrogel material based on porcine gelatin and sodium alginate was synthesized for use as a dressing for chronic wound treatment. The hydrogels were covalently cross-linked using polyethylene glycol diglycidyl ether (PEGDE 500), and the interaction between the components was confirmed via FTIR. The properties of the resulting hydrogels were examined, including gel-fraction volume, swelling degree in different media, mechanical properties, pore size, cytotoxicity, and the ability to absorb and release analgesics (lidocaine, novocaine, sodium diclofenac). The hydrogel’s resistance to enzymatic action by protease was enhanced both through chemical cross-linking and physical interactions between gelatin and alginate. The absorption capacity of the hydrogels, reaching 90 g per dm² of the hydrogel dressing, indicates their potential for absorbing wound exudates. It was demonstrated that the antiseptic (chlorhexidine) contained in the structured gelatin–alginate hydrogels can be released into an infected substrate, resulting in a significant inhibition of pathogenic microorganisms (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus niger). These results clearly demonstrate that the obtained hydrogel materials can serve as non-traumatic dressings for the treatment of chronic and/or infected wounds.

The work presents the results of research on the formation of a hydrogel polymer matrix during the gelatin crosslinking with a dioxirane derivative of poly(ethylene glycol) and experiments on studying their properties. The crosslinking process of type A gelatin using poly(ethylene glycol) diglycidyl ether (PEGDE 500) was optimized by changing the gelatin: PEGDE ratio without using any other factors. The properties of the obtained hydrogels were studied, in particular the gel fraction amount, the degree of swelling in different media, mechanical properties, pore size, cytotoxicity, the ability to absorb and release antiseptic drugs, and bactericidal properties of hydrogel samples filled with an antiseptic agent (chlorhexidine). The crosslinking reaction has been found to be the most efficient at gelatin: PEGDE 500 ratio ranging from 1:3 to 1:5. In this case, the formation of highly elastic hydrogels with maximum fraction amount and high mechanical properties was observed (the samples were not destroyed under compression). Moreover, only within this ratio range, the obtained hydrogels retained their shape when heated to 40 °C. The pore sizes of the swollen hydrogel clearly depend on the crosslinker content. The high values of the degree of swelling in the exudate-simulating fluid in combination with mechanical strength allow the development of wound dressings based on hydrogels of the developed composition. Crosslinking of gelatin with PEGDE 500 allows to obtain gelatin-based hydrogels in a controlled manner which does not require subsequent purification steps. The resulting material does not exhibit cytotoxicity during in vitro studies on living cells. The hydrogel filled with an antiseptic drug is capable of releasing it by 50% within the first day into the medium of saline and exudate-simulating fluid. The antimicrobial properties of the hydrogel containing chlorhexidine are confirmed by the effective inhibition of the growth of Escherichia coli and Staphylococcus aureus bacteria.

This study examines the kinetic profiles of lidocaine hydrochloride, novocaine hydrochloride, and diclofenac sodium release from gelatin–alginate hydrogels crosslinked with poly(ethylene glycol) diglycidyl ether. Drug release was evaluated in phosphate-buffered saline (PBS) and in PBS supplemented with a proteolytic enzyme using a Franz diffusion cell. The experimental data were fitted to zero-order and first-order kinetic models, as well as the Higuchi, Hixson–Crowell, and Korsmeyer–Peppas models. Among these, the Higuchi model demonstrated the highest correlation for all tested drugs, indicating a diffusion-controlled release mechanism. The diffusion exponent n for lidocaine and novocaine (n < 0.5) corresponds to Fickian diffusion, whereas diclofenac (n > 0.5) exhibits anomalous diffusion behavior. The presence of a protease in the release medium accelerated drug liberation due to partial degradation of the polymer matrix.