The relevance of the amorphous state to pharmaceutical dosage forms: glassy drugs and freeze dried systems

Duncan Q.M. Craig, Paul G. Royall, Victoria Kett, Michelle L. Hopton

Research output: Contribution to journalArticlepeer-review

366 Citations (Scopus)
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Abstract

Many pharmaceuticals, either by accident or design, may exist in a total or partially amorphous state. Consequently, it is essential to have an understanding of the physico-chemical principles underpinning the behaviour of such systems. In this discussion, the nature of the glassy state will be described, with particular emphasis on the molecular processes associated with glass transitional behaviour and the use of thermal methods for characterising the glass transition temperature, Tg. The practicalities of such measurements, the significance of the accompanying relaxation endotherm and plasticization effects are considered. The advantages and difficulties associated with the use of amorphous drugs will be outlined, with discussion given regarding the problems associated with physical and chemical stability. Finally, the principles of freeze drying will be described, including discussion of the relevance of glass transitional behaviour to product stability.
Original languageEnglish
Pages (from-to)179-207
Number of pages29
JournalInternational Journal of Pharmaceutics
Volume179
Issue number2
DOIs
Publication statusPublished - 15 Feb 1999

ASJC Scopus subject areas

  • Pharmaceutical Science

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