Water sorption and glass transition behaviors of freeze-dried sucrose-dextran mixtures

Koreyoshi Imamura, Atsushi Fukushima, Keisuke Sakaura, Takuo Sugita, Takaharu Sakiyama, Kazuhiro Nakanishi

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

The water sorption and glass transition behaviors of freeze-dried disaccharide-polysaccharide mixtures at various contents were investigated at relative humidities (RHs) of 0, 11, 23, and 33%. Sucrose and three types of dextrans, which differ in molecular weight, were used as model di- and polysaccharides, respectively. The relationship between the dextran and water contents of the sucrose-dextran mixture at different constant RHs indicated that a mixture of sucrose and dextran was lower than that calculated by the Lang and Steinberg mass balance equation. In the RH range of 0-23%, the glass transition temperature, Tg, increased to a considerable extent when the dextran content was equal to or higher than 50%, while the increase in Tg at dextran contents lower than 50% was small. A marked increase in Tg was observed at RH 33% for dextran contents of 0-25% as well as in the range above 50%. This suggests that the physical stability of the highly hydrated amorphous disaccharide is effectively strengthened by the addition of a small amount of polysaccharide. These tendencies were similar for the three dextrans of different molecular weights. Furthermore, it was demonstrated that the addition of a small amount of dextran is quite effective in preventing the collapse of amorphous sugar during freeze drying.

Original languageEnglish
Pages (from-to)2175-2181
Number of pages7
JournalJournal of Pharmaceutical Sciences
Volume91
Issue number10
DOIs
Publication statusPublished - Oct 2002

Keywords

  • Disaccaride-polysacharide mixtures
  • Freeze drying
  • Glass transition
  • Water sorption

ASJC Scopus subject areas

  • Pharmaceutical Science

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