Heat processed triple polymer system of poly (vinyl alcohol)-polyvinylpyrrolidone-chitosan composite hydrogel containing Amphotericin B as a hydrogel wound dressing candidate

Abstract

This study developed and characterised poly(vinyl alcohol) (PVA)–polyvinylpyrrolidone (PVP)–chitosan composite hydrogels crosslinked with oxalic acid through thermal crosslinking as antifungal wound dressings loaded with amphotericin B (AMB). Hydrogel films were prepared from aqueous stock solutions with varying chitosan content and subjected to dry thermal treatment to induce crosslinking with oxalic acid. Increasing chitosan content significantly elevated the viscosity of the polymeric mixtures and influenced the swelling percentage and equilibrium water content. Conversely, the gel fraction remained largely unchanged, indicating enhanced water uptake without compromising structural integrity. FTIR spectroscopy confirmed successful network formation and chitosan incorporation. Leachable studies identified PVA and PVP as the primary leachate components. While AMB partitioning showed no statistical differences across formulations, the hydrogels maintained a mildly acidic surface pH. Notably, the AMB-loaded PPChi 20 hydrogel exhibited a significantly larger zone of inhibition against C. albicans compared to AMB-free controls. As blank formulations showed no antifungal activity, the efficacy was primarily dependent on the hydrogel’s AMB loading capacity. These findings suggest that PVA–PVP–chitosan hydrogels crosslinked with oxalic acid are promising candidates for topical AMB delivery in managing fungal-infected wounds.