title: Chitosan-xanthan gum microparticle-based oral tablet for colon-targeted and sustained delivery of quercetin.
abstract: BACKGROUND
  Quercetin (QUE) is a flavonoid with antioxidant/anti-inflammatory properties, poorly absorbed when orally administered.
  
  
  OBJECTIVE
  To prepare chitosan/xanthan gum microparticles to increase QUE oral bioavailability and optimize its release in the colon.
  
  
  METHODS
  Chitosan/xanthan gum hydrogel embedding QUE was spray-dried to obtain microparticles characterized by size, scanning electron microscopy, differential scanning calorimetry and X-ray diffraction. Microparticles were compressed into tablets, coated with Eudragit® to further prevent degradation in acidic pH. The swelling degree and QUE release in simulated gastric and intestinal pH were investigated.
  
  
  RESULTS
  Microparticles were smooth and spherical, around 5 µm, with successful QUE loading. Microparticle tablets provided resistance to acidic conditions, allowing complete drug release in alkaline pH, mimicking colonic environment. The release was controlled by non-Fickian diffusion of the dissolved drug out of the swollen polymeric tablet.
  
  
  CONCLUSIONS
  Microparticle tablets represent a promising dosage form for QUE delivery to the colon in the oral therapy of inflammatory-based disorders.
authors.affiliation: Department Scienze della Vita e dell'Ambiente, Sezione Scienze del Farmaco , University of Cagliari, Cagliari , Italy .
authors.forename: Carla
authors.initials: C
authors.lastname: Caddeo
authors.forename: Amparo
authors.initials: A
authors.lastname: Nácher
authors.forename: Octavio
authors.initials: O
authors.lastname: Díez-Sales
authors.forename: Matilde
authors.initials: M
authors.lastname: Merino-Sanjuán
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Fadda
authors.forename: Maria
authors.initials: M
authors.lastname: Manconi
mesh_terms: D000284:Administration, Oral; D000975:Antioxidants / Q000737:chemistry / Q000493:pharmacokinetics; D048271:Chitosan / Q000737:chemistry / Q000493:pharmacokinetics; D003106:Colon; D003692:Delayed-Action Preparations; D006863:Hydrogen-Ion Concentration; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000493:pharmacokinetics; D011794:Quercetin / Q000737:chemistry / Q000493:pharmacokinetics; D013607:Tablets
chemical_list: D000975:Antioxidants; D003692:Delayed-Action Preparations; D011135:Polysaccharides, Bacterial; D013607:Tablets; D048271:Chitosan; D011794:Quercetin; C002563:xanthan gum
keywords: Chitosan; colon drug delivery; microparticle tablets; microparticles; quercetin; xanthan gum