Abstract
Understanding phase transitions in pharmaceutical materials is of vital importance for drug manufacturing, processing and storage. In this paper we have carried out comprehensive high-resolution spectroscopic studies on the polymorphs of the non-steroidal anti-inflammatory drug diflunisal that has four known polymorphs, forms I–IV (FI–FIV), three of which have known crystal structures. Phase transformations during milling, heating, melt-quenching and exposure to high relative humidity were investigated using Raman and terahertz spectroscopy in combination with differential scanning calorimetry and X-ray powder diffraction. The observed phase transformations indicate the stability order FIII > FI > FII, FIV. Furthermore, crystallization experiments from the gas phase and from solution by fast evaporation of different solvents were carried out. Fast evaporation of an ethanolic solution below 70 °C was identified as a reliable and convenient method to obtain the somewhat elusive FII in bulk quantities.
Original language | English |
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Pages (from-to) | 312-321 |
Number of pages | 10 |
Journal | International Journal of Pharmaceutics |
Volume | 528 |
Issue number | 1-2 |
Early online date | 8 Jun 2017 |
DOIs | |
Publication status | Published - Aug 2017 |
Keywords
- Diflunisal
- Phase transformation
- Polymorphs
- Terahertz spectroscopy
ASJC Scopus subject areas
- Pharmaceutical Science
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Chapman, S. (Manager)
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Raman confocal microscope RENISHAM INVIA
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