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

- A quercetin nanoemulsion (QCN) facilitated the intestinal permeability of QCN.
- A QCN-loaded nanoemulsion greatly improved the oral bioavailability of QCN in rats.
- A QCN-loaded nanoemulsion prevented weight gain in high-fat diet-treated mice.
- Oral nanoemulsions incorporating QCN may be useful for treating obesity.

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.