Curcumin release from hydrogels incorporated with turmeric extract–cyclodextrin complexes for wound dressing applications

Abstract

Curcumin, the major bioactive compound of turmeric, exhibits potent antioxidant and anti-inflammatory activities with significant therapeutic potential for wound healing. However, its clinical use is hindered by inherently poor water solubility. In this study, cyclodextrin (CD) inclusion complexes were prepared with turmeric extract (TE) to enhance the aqueous solubility and release of curcumin from hydrogels intended as active wound dressings. The TE-to-CD ratio was systematically varied from 10–80% (w/w), yielding complexes designated as 10TECD–80TECD formulations. Formulations below 20TECD exhibited superior aqueous solubility while retaining antioxidant activity. SEM analysis showed a morphological transition from large (∼5 µm) to smaller (∼1 µm) flake-like particles in formulations below 40TECD. The TECD complexes were subsequently incorporated into hydrogel sheets prepared from 3–8% (w/v) poly(vinyl alcohol) (PVA), which were crosslinked by freeze-thaw cycling followed by electron beam irradiation. Curcumin release was inversely related to PVA concentration, with the lowest concentration producing the most porous matrix structure and greatest surface area, thereby facilitating the highest release. The optimized formulation, consisting of a 3PVA hydrogel loaded with 20TECD, achieved a cumulative curcumin release of 13.25% within 6 h, with release characteristics consistent with Fickian diffusion kinetics. The system exhibited no cytotoxicity and also showed anti-inflammatory activity as confirmed by nitric oxide inhibition assay. These findings highlight the potential of TECD-loaded PVA hydrogels as effective bioactive wound dressing materials for curcumin delivery.