Preparation and characterization of drug-loaded chitosan-tripolyphosphate microspheres by spray drying

Kashappa Goud H. Desai, Hyun Jin Park

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109 Citations (Scopus)


The present study reports on the preparation of chitosan-tripolyphosphate (TPP) microspheres by the spray-drying method using acetaminophen as a model drug substance. Chitosan-TPP microspheres were spherical and had a smooth surface. Perfectly spherical chitosan-TPP microparticles loaded with acetaminophen were obtained in the size range of 3.1-10.1 μm. Spray-dried chitosan-TPP microspheres were positively charged (zeta potential ranged from +18.4 to +31.8). The encapsulation efficiency of these microspheres was in the range of 48.9-99.5%. The swelling capacity of chitosan-TPP microspheres increased with increases in the molecular weight of chitosan and decreases with increasing volume of 1% wt/vol TPP solution used for the cross-linking reaction. The effect of chitosan concentration, drug loading, volume of TPP solution used for cross-linking, and chitosan molecular weight on surface morphology and drug release rate was extensively investigated. Microparticles with spherical shape and slower release rates were obtained from chitosan-TPP microspheres prepared using a higher concentration of chitosan, higher volume of TPP solution, a higher molecular weight chitosan and/or a higher drug loading. Most importantly, the drug release rate was mainly controlled by the chitosan-TPP matrix density and, thus, by the degree of swelling of the hydrogel matrix. Drug release from chitosan-TPP microspheres occurred via diffusion as the best fit for drug release was obtained using the Higuchi equation.

Original languageEnglish
Pages (from-to)114-128
Number of pages15
JournalDrug Development Research
Issue number2
Publication statusPublished - 2005 Feb


  • Acetaminophen
  • Chitosan microspheres
  • Controlled release
  • Release kinetics
  • Spray drying
  • Swelling
  • Tripolyphosphate

ASJC Scopus subject areas

  • Drug Discovery


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