Comparison of three methods to find the vapor activity of a hydration step

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The formation of a stochiometric salt hydrate takes place at a well defined vapor activity. We have compared three methods to measure this vapor activity. In two of the methods we used a sorption balance in step mode and in ramp mode, respectively, and in one method we used a newly developed sorption microcalorimeter. The tests were made with the formation of morphine sulphate pentahydrate from its dihydrate at 25°C. With all three methods this transition was found to take place at a vapor activity close to 0.21.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Engineering
Original languageEnglish
Pages (from-to)77-81
JournalEuropean Journal of Pharmaceutics and Biopharmaceutics
Issue number1
Publication statusPublished - 2001
Publication categoryResearch