Dissolution and diffuse reflectance characteristics of coated theophylline particles

I. Antal, R. Zelkó, N. Röczey, J. Plachy, I. Rácz

Research output: Contribution to journalArticle

50 Citations (Scopus)


The aim of the present study was to investigate how the dissolution and diffuse reflectance characteristics of theophylline microcapsules were influenced by the changes in the thickness and by the plasticizer content of coating. Microencapsulation was carried out in laboratory fluidized-bed system using water dispersable Eudragit-type film coating polymer. United States Pharmacopeia rotating paddle method was applied for the in vitro dissolution study. The dissolution profile of the produced microcapsules was evaluated by Weibull distribution. The effect of the thickness of coating and that of the plasticizer content on the dissolution kinetics was modelled by a second-order polynomial equation fitted to the data gathered by a face-centered central composite statistical design. It was found that both of the examined coating parameters influenced the drug release kinetics. The diffuse reflectance spectra of the coated particles indicated the changes in coating parameters without destructive analysis of samples.

Original languageEnglish
Pages (from-to)83-89
Number of pages7
JournalInternational Journal of Pharmaceutics
Issue number1
Publication statusPublished - Sep 12 1997


  • Diffuse reflectance
  • Eudragit aqueous dispersion
  • Fluidized-bed coating
  • Modified theophylline release
  • Plasticizer

ASJC Scopus subject areas

  • Pharmaceutical Science

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