Co-delivery of hydrophobic curcumin and hydrophilic catechin by a water-in-oil-in-water double emulsion

Curcumin and catechin are naturally occurring phytochemicals with extreme sensitivity to oxidation and low bioavailability. We fabricated a water-in-oil-in-water (W/O/W) double emulsion encapsulating hydrophilic catechin and hydrophobic curcumin simultaneously. The co-loaded emulsion was fabricated using a two-step emulsification method, and its physicochemical properties were characterised. Volume-weighted mean size (d(43)) of emulsion droplets was approximate to 3.88 mu m for blank emulsions, whereas it decreased to approximate to 2.8-3.0 mu m for curcumin and/or catechin-loaded emulsions, which was attributed to their capacity to act as emulsifiers. High entrapment efficiency was observed for curcumin and/or catechin-loaded emulsions (88-97%). Encapsulation of catechin and curcumin within an emulsion increased their stability significantly in simulated gastrointestinal fluid, which resulted in a four-fold augmentation in their bio-accessibility compared to that of freely suspended curcumin and catechin solutions. Co-loading of curcumin and catechin did not have adverse effects on either compound's stability or bioaccessibility. (C) 2014 Elsevier Ltd. All rights reserved.