Preparation of cross-linked chitosan microspheres by spray drying: effect of cross-linking agent on the properties of spray dried microspheres

J Microencapsul. 2005 Jun;22(4):377-95. doi: 10.1080/02652040500100139.

Abstract

Chitosan microspheres cross-linked with three different cross-linking agents viz, tripolyphosphate (TPP), formaldehyde (FA) and gluteraldehyde (GA) have been prepared by spray drying technique. The influence of these cross-linking agents on the properties of spray dried chitosan microspheres was extensively investigated. The particle size and encapsulation efficiencies of thus prepared chitosan microspheres ranged mainly between 4.1-4.7 microm and 95.12-99.17%, respectively. Surface morphology, % erosion, % water uptake and drug release properties of the spray dried chitosan microspheres was remarkably influenced by the type (chemical or ionic) and extent (1 or 2% w/w) of cross-linking agents. Spray dried chitosan microspheres cross-linked with TPP exhibited higher swelling capacity, % water uptake, % erosion and drug release rate at both the cross-linking extent (1 and 2% w/w) when compared to those cross-linked with FA and GA. The sphericity and surface smoothness of the spray dried chitosan microspheres was lost when the cross-linking extent was increased from 1 to 2% w/w. Release rate of the drug from spray dried chitosan microspheres decreased when the cross-linking extent was increased from 1 to 2% w/w. The physical state of the drug in chitosan-TPP, chitosan-FA and chitosan-GA matrices was confirmed by the X-ray diffraction (XRD) study and found that the drug remains in a crystalline state even after its encapsulation. Release of the drug from chitosan-TPP, chitosan-FA and chitosan-GA matrices followed Fick's law of diffusion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetaminophen / administration & dosage
  • Analgesics, Non-Narcotic / administration & dosage
  • Chitosan / chemistry*
  • Cross-Linking Reagents / chemistry
  • Delayed-Action Preparations
  • Desiccation
  • Drug Carriers / chemistry*
  • Formaldehyde / chemistry
  • Glutaral / chemistry
  • Microscopy, Electron, Scanning
  • Microspheres*
  • Particle Size
  • Polyphosphates / chemistry

Substances

  • Analgesics, Non-Narcotic
  • Cross-Linking Reagents
  • Delayed-Action Preparations
  • Drug Carriers
  • Polyphosphates
  • Formaldehyde
  • Acetaminophen
  • Chitosan
  • triphosphoric acid
  • Glutaral