Acoustic and thermal anomalies in a liquid–glass transition of racemic S(+)–R(−) ketoprofen

Arrhenius plot of relaxation times of ketoprofen. •Acoustic and thermal properties of racemic S(+)–R(−) ketoprofen were investigated.•Glassy ketoprofen exhibited a clear change at the glass transition temperature.•The fragility index m=71 was determined.•New relaxation map was suggested in combinati...

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Bibliographic Details
Published in:Chemical physics letters 2014-01, Vol.592, p.80-84
Main Authors: Shibata, Tomohiko, Takayama, Haruki, Kim, Tae Hyun, Kojima, Seiji
Format: Article
Language:English
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Summary:Arrhenius plot of relaxation times of ketoprofen. •Acoustic and thermal properties of racemic S(+)–R(−) ketoprofen were investigated.•Glassy ketoprofen exhibited a clear change at the glass transition temperature.•The fragility index m=71 was determined.•New relaxation map was suggested in combination with previous study. Acoustic and thermal properties of pharmaceutical racemic S(+)–R(−) ketoprofen were investigated in wide temperature range including glassy, supercooled liquid and liquid states by Brillouin scattering and temperature modulated DSC. Sound velocity and acoustic attenuation exhibited clear changes at 265K indicating a liquid–glass transition and showed the typical structural relaxation above Tg. The high value of the fragility index m=71 was determined by the dispersion of the complex heat capacity. New relaxation map was suggested in combination with previous study of dielectric measurement.
ISSN:0009-2614
1873-4448
DOI:10.1016/j.cplett.2013.12.003