Preparation of nanoemulsions containing herbal derivatives: a dynamic light scattering analysis

Citral and quercetin are, respectively, a monoterpene and a flavonoid of great interest for cosmetics. They have impaired water solubility, and the development of nanoemulsions is a suitable strategy to overcome this main issue. In this study, citral was used as the oily phase to nanoemulsify quercetin through a low-energy method. The nanoemulsions were prepared with deionized water or glycerol, and the best results were reached with polysorbate 80 and water, being observed a size diameter of around 20 nm and a relatively monodisperse distribution. Quercetin was capable of reducing droplet size when compared to citral, a mandatory component for classifying this colloid as a nanoemulsion. Up to 65ºC, there was no main difference in droplet size. Therefore, this study provides suitable prototypes of citral/quercetin nanoemulsion that can be further used in cosmetic applications through an eco-friendly method of preparation.