Fate of curcumin encapsulated in silica nanoparticle stabilized Pickering emulsion during storage and simulated digestion

Stability and release of curcumin was evaluated in silica nanoparticle stabilized Pickering emulsion during storage and simulated gastric and intestinal digestion. Stability and release kinetics of curcumin were characterized based on spectrophotometric measurements to quantify the amount of encapsulated curcumin in Pickering emulsion as a function of time. Physical stability of the emulsion during digestion was characterized using particle size, zeta potential and fluorescence imaging measurements. Biocompatibility of the emulsion and intracellular delivery of a model lipophilic fluorescent compound encapsulated in the emulsion were also determined. Stability of curcumin encapsulated in emulsion was approximately 100 fold higher than the stability of curcumin suspended in distilled water. Passive release measurements showed sustained release of over 80% of the encapsulated curcumin in 36 h. During simulated gastric digestion (2 h), over 80% of the encapsulated curcumin was retained, although limited aggregation of the emulsion droplets was observed. Incubation in simulated intestinal environment resulted in destabilization of the emulsion and approximately 60% of the encapsulated curcumin was released within 2 h of incubation. Fluorescence imaging measurements showed successful cellular uptake of emulsion droplets. Overall, this study demonstrates that Pickering emulsion has a potential for effective delivery of bioactive compounds. (C) 2013 Elsevier Ltd. All rights reserved.