Preparation and Characterization of Quercetin Nanocrystals

This study is to enhance the dissolution rate of a poorly water-soluble drug, quercetin, by fabricating nanocrystals using high-pressure homogenization. The particle size, crystallinity, dissolution, and antioxidant effects of fabricated quercetin nanocrystals have been investigated. Characterization of the original quercetin powder and nanocrystals was carried out by photon correlation spectroscopy (PCS), laser diffraction, scanning electron microscopy, differential scanning calorimetry (DSC), X-ray diffraction, dissolution tester, and so on. A PCS size of about 483nm was obtained for the nanocrystals after 20 cycles of homogenization at 1500 bar. X-ray diffraction and DSC studies revealed that the lyophilized quercetin nanoparticles were crystalline after high-pressure homogenization. The percent dissolution efficiency, relative dissolution, mean dissolution time, difference factor (f(1)), and similarity factor (f(2)) were calculated for the statistical analysis. It was found that the dissolution of the drug nanocrystals was much higher than that of the pure drug at pH 6.8 and 1.2. The antioxidant activity and reducing power of the quercetin nanocrystals were more effective than the original quercetin. (C) 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:2379-2390, 2011