title: Spray-dried O-carboxymethyl chitosan as potential hydrophilic matrix tablet for sustained release of drug.
abstract: OBJECTIVE
  The aim of the present investigation was to evaluate the use of spray-dried O-carboxymethyl chitosan (OCMCS) as potential hydrophilic matrix excipient for sustained release of drug.
  
  
  METHODS
  The polymer was synthesized from chitosan, then spray-dried and characterized. Tablets with different OCMCS concentrations (80, 50, 30, 5 and 2% w/w), containing diltiazem (DTZ) as model drug, were prepared for direct compression (DC) and after the wet granulation method (WG).
  
  
  RESULTS
  The spray-dried OCMCS powder was spherical, with a smooth surface and an average size of 2.2 µm. The tablets prepared for WG disintegrated in time less than 30 min. The tablets obtained for DC presented high retention of the drug, with zero order or Higuchi release kinetic. There was a direct relationship between the OCMCS concentration and the release ratio, swelling degree and water uptake behavior. DC tablets containing 80% OCMCS presented behavior as an effective swelling-control system. The DC tablets with 5% OCMCS showed a similar release profile at formulations with 30% HPMC.
  
  
  CONCLUSIONS
  Spray-dried OCMCS showed great potential as hydrophilic matrices for drug-sustained release.
authors.affiliation: Núcleo de Investigações Químico-Farmacêuticas (NIQFAR), Programa de Mestrado em Ciências Farmacêuticas, Universidade do Vale do Itajaí (UNIVALI) , Itajaí, SC , Brazil.
authors.forename: José R
authors.initials: JR
authors.lastname: Bresolin
authors.forename: Maria-Claudia T
authors.initials: MC
authors.lastname: Largura
authors.forename: Camila C
authors.initials: CC
authors.lastname: Dalri
authors.forename: Geórgia
authors.initials: G
authors.lastname: Hoffer
authors.forename: Clóvis A
authors.initials: CA
authors.lastname: Rodrigues
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Lucinda-Silva
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D003692:Delayed-Action Preparations; D004110:Diltiazem / Q000008:administration & dosage*; D005079:Excipients / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000737:chemistry; D013499:Surface Properties; D013607:Tablets
chemical_list: D003692:Delayed-Action Preparations; D005079:Excipients; C504164:O-carboxymethylchitosan; D013607:Tablets; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D048271:Chitosan; D004110:Diltiazem