Characterization of local delivery with amphotericin B and vancomycin from modified chitosan sponges and functional biofilm prevention evaluation.

Polymicrobial musculoskeletal wound infections are troublesome complications and can be difficult to treat when caused by invasive fungi or bacteria. However, few local antifungal delivery systems have been studied. Chitosan and polyethylene glycol (PEG) sponge local antifungal delivery systems have been developed for adjunctive therapy to reduce musculoskeletal wound contamination. This study evaluated the effects of blending PEG, at 6,000 or 8,000 g/mol, with chitosan in sponge form on in vitro amphotericin B and vancomycin elution, eluate activity, cytocompatibility, and in vivo prevention of a bacterial biofilm. Blended chitosan sponges released both amphotericin B and vancomycin in vitro. All tested amphotericin B eluates remained active against Candida albicans, and vancomycin eluates from blended sponges maintained activity against Staphylococcus aureus. Amphotericin B eluates obtained after 1 h from blended sponges elicited 62-95% losses in fibroblast viability, but 3 h eluates only caused 22-60% decreases in viability. In a Staphylococcus aureus infected mouse catheter biofilm prevention model, vancomycin loaded chitosan/PEG 6000 sponge cleared bacteria from 100% of the catheters, with reduced clearance rate observed in other sponges. These results indicate that the chitosan/PEG blended sponges have potential for local antifungal and/or antibiotic combination delivery as an adjunctive therapy to prevent wound infections.