Characteristics of hydrogen bond formation between sugar and polymer in freeze-dried mixtures under different rehumidification conditions and its impact on the glass transition temperature

Koreyoshi Imamura, Yoko Asaimo, Yoshinobu Maruyama, Tohru Yokoyama, Mayo Nomura, Seiji Ogawa, Kazuhiro Nakanishi

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The characteristics of hydrogen bond formation between trehalose and polyvinylpyrrolidone (PVP) in amorphous mixtures at different hydration states were quantitatively investigated. Amorphous trehalose-PVP mixtures were prepared by freeze-drying and equilibrated at different relative humidities (RH). Infrared (IR) spectra of the trehalose-PVP mixtures were obtained by Fourier transform IR spectroscopy, (FTIR) and the IR band corresponding to C=O groups of PVP was deconvolved into the component bands responsible for C=O groups that were free and restricted by hydrogen bonds, to estimate the degree of the trehalose-PVP interactions. The FTIR analysis indicated that approximately 80% of the C=O groups of PVP formed hydrogen bonds with trehalose in the presence of more than 3 g of trehalose per gramme of PVP, independent of the RH. IR analysis of the O-H stretching vibration of the sugar demonstrated that the presence of PVP lead to an increase in the free hydroxyl groups of trehalose that did not form hydrogen bonds at RH 0%. On the other hand, the water sorption behavior of the trehalose-PVP mixtures suggested that rehumidification diminished the effect of PVP on increasing the free OH groups. Thus a peculiar relationship may exist between Tg, RH and the composition of the mixture: The presence of PVP increased Tg at RHs 0 and above 23% but decreased Tg at 11%.

Original languageEnglish
Pages (from-to)1301-1312
Number of pages12
JournalJournal of Pharmaceutical Sciences
Volume97
Issue number3
DOIs
Publication statusPublished - Mar 2008

Keywords

  • Amorphous
  • Excipients
  • FTIR
  • Freeze-drying
  • Glass transition
  • Polymers

ASJC Scopus subject areas

  • Pharmaceutical Science

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