Fabrication and In Vitro/Vivo Evaluation of Drug Nanocrystals Self-Stabilized Pickering Emulsion for Oral Delivery of Quercetin.

The aim of this study was to develop a new drug nanocrystals self-stabilized Pickering emulsion (NSSPE) for improving oral bioavailability of quercetin (QT). Quercetin nanocrystal (QT-NC) was fabricated by high pressure homogenization method, and QT-NSSPE was then prepared by ultrasound method with QT-NC as solid particle stabilizer and optimized by Box-Behnken design. The optimized QT-NSSPE was characterized by fluorescence microscope (FM), scanning electron micrograph (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The stability, in vitro release, and in vivo oral bioavailability of QT-NSSPE were also investigated. Results showed that the droplets of QT-NSSPE with the size of 10.29 ± 0.44 μm exhibited a core-shell structure consisting of a core of oil and a shell of QT-NC. QT-NSSPE has shown a great stability in droplets shape, size, creaming index, zeta potential, and QT content during 30 days storage at 4, 25, and 40 °C. In vitro release studies showed that QT-NSSPE performed a better dissolution behavior (65.88% within 24 h) as compared to QT-NC (50.71%) and QT coarse powder (20.15%). After oral administration, the AUC of QT-NSSPE was increased by 2.76-times and 1.38 times compared with QT coarse powder and QT-NC. It could be concluded that NSSPE is a promising oral delivery system for improving the oral bioavailability of QT.