title: Production and characterization of a spray-dried hydroxypropyl-beta-cyclodextrin/quercetin complex.
abstract: BACKGROUND
  Quercetin (QC) is a poorly water-soluble and degradation-prone bioflavonoid.
  
  
  OBJECTIVE
  This study aimed to investigate the formation of a chemically stable and readily water-soluble solid complex of QC with hydroxypropyl-beta-cyclodextrin (HP-beta-CD).
  
  
  METHODS
  A solid HP-beta-CD/QC complex was prepared by spray drying and characterized by high-performance liquid chromatography, Fourier-transform infrared spectroscopy, scanning electron microscopy, laser-diffraction particle sizing, powder X-ray diffraction, thermal analysis, Brunauer-Emmett-Teller nitrogen adsorption, and dissolution testing.
  
  
  RESULTS
  The complex displayed excellent thermal stability during spray drying, a broad diffuse X-ray diffraction pattern, and a single glass transition temperature (T(g)) characteristic of amorphous HP-beta-CD. Dissolution testing of the complex in simulated gastric fluid revealed an approximately eightfold increase in the rate and extent of dissolution of QC compared with its molar equivalent physical mixture of QC and blank spray-dried HP-beta-CD, although the surface area of QC in the mixture was about seven times that of the complex.
  
  
  CONCLUSIONS
  All these observations can be explained by specific interaction between QC and HP-beta-CD in the amorphous solid state, possibly in the form of an inclusion complex.
authors.affiliation: Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Albert H L
authors.initials: AH
authors.lastname: Chow
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000975:Antioxidants / Q000737:chemistry*; D004355:Drug Stability; D005079:Excipients / Q000737:chemistry*; D006358:Hot Temperature; D010316:Particle Size; D011794:Quercetin / Q000737:chemistry*; D012995:Solubility; D044366:Transition Temperature; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D005079:Excipients; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D011794:Quercetin