An assessment of the interactions between diclofenac sodium and ammonio methacrylate copolymer using thermal analysis and Raman spectroscopy

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25 Citations (Scopus)

Abstract

The objective of the work was to assess the possible interactions between the model drug diclofenac sodium (DS) and the water-insoluble ammonio methacrylate copolymer (AMC). Films with different drug/polymer ratios were therefore prepared by the solvent casting method and investigated as a preformulation study towards sustained release microparticles. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to investigate the dispersed/dissolved state of the DS in the preparation, the thermal stability and the properties of DS-containing AMC films; and Raman spectroscopy was used to confirm the possible interactions between DS and AMC. Thermoanalytical studies confirmed that the DS could behave as a plasticizer, which was indicated by decreasing glass transition temperature (Tg) of the AMC, depending on its dispersity level in the AMC matrix. Partially solid solutions were formed at DS/AMC ratios of 1:12, 1:8 and 1:6. The DS was mainly crystalline at DS/AMC ratio of 1:4, while it remained crystalline at a ratio of 1:2. The Raman spectra confirmed that none of the major structural changes revealed any significant difference, which can indicate a strong ionic interaction between the DS and the AMC. The investigations provided good facilities for the selection of a DS/AMC ratio, in the preformulation study of the microsphere preparation process, in conformity with the therapeutic aim.

Original languageEnglish
Pages (from-to)288-294
Number of pages7
JournalJournal of Pharmaceutical and Biomedical Analysis
Volume46
Issue number2
DOIs
Publication statusPublished - Jan 22 2008

Keywords

  • Ammonio methacrylate copolymer
  • Diclofenac sodium
  • Preformulation
  • Raman spectroscopy
  • Solvent casting method
  • Thermoanalysis

ASJC Scopus subject areas

  • Analytical Chemistry
  • Pharmaceutical Science
  • Drug Discovery
  • Spectroscopy
  • Clinical Biochemistry

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