Oral delivery of quercetin in oil-in-water nanoemulsion: In vitro characterization and in vivo anti-obesity efficacy in mice

We sought to design an effective oral delivery system for quercetin (QCN) to enhance its solubility and bioavailability and thus improve its anti-obesity effects. QCN-loaded oil-in-water nanoemulsion was prepared by an aqueous phase titration method. The optimized formulation had a mean particle size of 19.3 ± 0.17 nm with a zeta potential of −0.34 ± 0.13 mV. In vitro permeabilities of QCN from the nanoemulsion through an artificial intestinal membrane and Caco-2 cell monolayer were 188- and 3.37-fold higher than those of an aqueous dispersion of QCN, respectively, and the resulting in vivo oral bioavailability was 33.51-fold greater than that of free QCN. Furthermore, high-fat-diet (HFD)-treated mice given daily the oral QCN-loaded nanoemulsion had a maximal reduced weight gain of 23.5% compared with the HFD control group. These findings suggest that a QCN-loaded nanoemulsion may be a promising oral therapy for the treatment of obesity.