Characteristics of vitamin C encapsulated tripolyphosphate-chitosan microspheres as affected by chitosan molecular weight

K. G. Desai, C. Liu, Hyunh Jin Park

Research output: Contribution to journalArticlepeer-review

60 Citations (Scopus)

Abstract

In this paper, the effect of chitosan molecular weight on the characteristics (size, encapsulation efficiency, zeta potential, surface morphology and release rate) of vitamin C encapsulated tripolyphosphate cross-linked chitosan (TPP-chitosan) microspheres. The molecular weight of chitosan had a noticeable influence on the size, encapsulation efficiency, zeta potential, surface morphology and controlled release behaviour of the vitamin C encapsulated TPP-chitosan microspheres. The mean particle size and encapsulation efficiencies of TPP-chitosan microspheres were 3.1, 4.9 and 6.7 μm and 67.25, 60.43 and 52.74% for the microspheres prepared using low, medium and high molecular weight chitosan, respectively. All the TPP-chitosan microspheres (low, medium and high molecular weight) had positive charge on their surface. The zeta potential of the TPP-chitosan microspheres prepared using low, medium and high molecular weight chitosan was 41.25, 40.84 and 39.13 mV, respectively. The particle sizes of TPP-chitosan microspheres increased with increases in chitosan molecular weight. Molecular weight of chitosan did not affect significantly the % yield of TPP-chitosan microspheres prepared by spray-drying. The influence of chitosan molecular weight on the surface morphology of vitamin C encapsulated TPP-chitosan microspheres was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was observed that, as the molecular weight of chitosan increases, TPP-chitosan microspheres with uniform spherical shape could be obtained. The physical state of vitamin C (amorphous or crystalline) in TPP-chitosan matrix was studied by X-ray diffraction (XRD) and it was found that vitamin C is dispersed at the molecular level (amorphous) in the TPP-chitosan matrix. Release rate of the vitamin C from TPP-chitosan microspheres was significantly affected by the chitosan molecular weight. The release rate decreased with increase in the chitosan molecular weight. The release of vitamin C from TPP-chitosan microspheres followed Fick's law of diffusion.

Original languageEnglish
Pages (from-to)79-90
Number of pages12
JournalJournal of Microencapsulation
Volume23
Issue number1
DOIs
Publication statusPublished - 2006 Feb

Keywords

  • Chitosan
  • Controlled release
  • Encapsulation
  • Microspheres
  • Molecular weight
  • Tripolyphosphate
  • Vitamin C

ASJC Scopus subject areas

  • Bioengineering
  • Pharmaceutical Science
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Colloid and Surface Chemistry

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