Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering
1
Agency for Defense Development, P.O. Box 35, Yuseong, Daejeon 34186, Korea
2
Department of Chemistry, Hallym University, Chuncheon, Gangwon-do 24252, Korea
3
Department of Physics, Hallym University, Chuncheon, Gangwon-do 24252, Korea
*
Author to whom correspondence should be addressed.
Materials 2017, 10(12), 1426; https://doi.org/10.3390/ma10121426
Received: 14 October 2017
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Revised: 10 December 2017
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Accepted: 13 December 2017
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Published: 14 December 2017
(This article belongs to the Special Issue Characterization of Amorphous Materials)
The amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties of amorphous progesterone, one of the representative steroid hormones, were investigated by using a Brillouin inelastic light scattering technique. The Brillouin spectrum of the longitudinal acoustic mode exhibited distinct changes at the glass transition and the cold-crystallization temperatures. The acoustic dispersions of the longitudinal sound velocity and the acoustic absorption coefficient were attributed to the fast and possibly the secondary relaxation processes in the glassy and supercooled liquid states, while the structural relaxation process was considered as the dominant origin for the significant acoustic damping observed even in the liquid phase. The persisting acoustic dispersion in the liquid state was attributed to the single-molecule nature of the progesterone which does not exhibit hydrogen bonds in the condensed states.
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Keywords:
progesterone; pharmaceutical; glass; Brillouin scattering; acoustic
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MDPI and ACS Style
Kim, T.H.; Yoo, H.; Ko, J.-H. Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering. Materials 2017, 10, 1426. https://doi.org/10.3390/ma10121426
AMA Style
Kim TH, Yoo H, Ko J-H. Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering. Materials. 2017; 10(12):1426. https://doi.org/10.3390/ma10121426
Chicago/Turabian StyleKim, Tae H., Hyojong Yoo, and Jae-Hyeon Ko. 2017. "Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering" Materials 10, no. 12: 1426. https://doi.org/10.3390/ma10121426
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