BUSCADOR RECOLECTA

The aim of this work was to optimize the preparative process of quercetin loaded casein nanoparticles as well as
to evaluate the pharmacokinetics of this flavonoid when administered orally in Wistar rats. Nanoparticles were
obtained by coacervation after the incubation of casein, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and quercetin in an aqueous environment. Then, nanoparticles were purified and dried. The resulting nanoparticles
displayed a size of 200 nm with a negative zeta potential and a payload of about 32 μg/mg. Release studies
showed a zero-order kinetic, suggesting a mechanism based on erosion of the nanoparticle matrix. For the
pharmacokinetic study, quercetin was orally administered to rats as a single dose of 25 mg/kg. Animals treated
with quercetin-loaded casein nanoparticles displayed higher plasma levels than those observed in animals receiving the solution of the flavonoid (control). Thus, the relative oral bioavailability of quercetin when administered as casein nanoparticles (close to 37%) was found to be about 9-times higher than the oral solution of
the flavonoid in a mixture of PEG 400 and water. In summary, the combination of casein and 2-hydroxypropyl-βcyclodextrin produces nanoparticles that may be a good option to load quercetin for both nutraceutical and
pharmaceutical purposes., This work was supported by the Regional Government of Navarra (Alimentos funcionales, Euroinnova call) and the Spanish Ministry of Science and Innovation and Gobierno de Navarra, Spain (ADICAP; ref. IPT-2011-1717-900000). Rebeca Penalva acknowledges the “Asociación de Amigos Universidad de Navarra” for the financial support.