Formulation and Bacterial Phototoxicity of Curcumin Loaded Alginate Foams for Wound Treatment Applications: Studies on Curcumin and Curcuminoides XLII

ABSTRACTCurcumin loaded alginate foams are proposed for application in antimicrobial photodynamic therapy of infected wounds. The drug loaded foams were formulated to provide a burst release of the photosensitizer when hydrated. The foams remained intact after hydration and would be possible to remove from the wound prior to irradiation without causing any tissue damage. The characterization of the prepared foams showed that both curcumin loaded and unloaded foams hydrated within 1 min and absorbed from 12 to 16 times their dry weight of a model physiological fluid. Curcumin, the model photosensitizer, has an extremely low solubility in water and may aggregate in aqueous environment. Cyclodextrins (CDs) and polyethylene glycol 400 (PEG 400) were therefore selected as solubilizers of curcumin in the foams to provide a burst release of the photosensitizer. Exposure to the prepared foams in combination with visible light irradiation (∼9.7 J/cm2) resulted in > 6 log reduction of Entrococcus faecalis cells. However, curcumin mediated photokilling of Escherichia coli was ineffective when CDs were selected as solubilizer of curcumin in the foams. An 81% reduction in viable E. coli cells was detected after treatment with the foam containing PEG 400 as the only solubilizer of curcumin combined with visible light irradiation (∼29 J/cm2).