Polyphenols are a large group of structurally diverse natural products, including flavonoids. One of the most
bioactive compounds of this class is the flavonol quercetin, a recognized antioxidant. Despite several studies were carried
out aiming to develop nanoformulations with secondary metabolites, to our knowledge, quercetin was not used as raw material
for nanodispersion production without coating polymers. This type of nanosize formulation is often prepared using
organic solvents and quercetin nanodispersions were prepared by emulsification evaporation technique, using 16.22 experimental
factorial design, (“surfactant type” evaluated at 6 levels, “surfactant amount” and “stirring speed” evaluated at
2 levels). Variance analysis, after one day of nanodispersions preparation, revealed that only the surfactant type was statistically
significant on particle size, while none of factors presented statistically significant effect on polydispersity index.
Variance analysis after seven days of nanodispersions preparation revealed that either surfactant type and surfactant
amount presented significant effect on particle size, while only surfactant type influenced polydispersity index. Some
nanodispersions presented small diameter and narrow size distribution, suggesting potential stability of these systems.
Special attention was given to nanodispersion prepared with 3 % (w/w) of polyethylene glycol 400 monooleate (expressed
as function of surfactant concentration at aqueous phase). It presented mean droplet size of 129.4 ± 0.5 nm and polydispersity
index of 0.173 ± 0.018, after 7 days of preparation. Low polydispersity index indicates a high homogeneity concerning
particle size distribution and suggests stability of the system. Moreover, absence of coating polymers and utilization
of a low energy method would be an advantage in terms of reducing costs for industrial application, without any