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Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression

Compression effects on alpha and beta relaxation process of amorphous drugs are theoretically investigated by developing the elastically collective nonlinear Langevin equation theory. We describe the structural relaxation as a coupling between local and nonlocal activated process. Meanwhile, the sec...

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Main Authors:	Anh D. Phan, Katsunori Wakabayashi
Format:	Article
Language:	English
Published:	MDPI 2020
Subjects:	compression effects amorphous drugs structural relaxation secondary relaxation glass transition molecular dynamics indomethacin curcumin glibenclamide
Online Access:	https://dlib.phenikaa-uni.edu.vn/handle/PNK/401 https://doi.org/10.3390/pharmaceutics12020177
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spelling	oai:localhost:PNK-4012022-08-17T05:54:37Z Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression Anh D. Phan Katsunori Wakabayashi compression effects amorphous drugs structural relaxation secondary relaxation glass transition molecular dynamics indomethacin curcumin glibenclamide Compression effects on alpha and beta relaxation process of amorphous drugs are theoretically investigated by developing the elastically collective nonlinear Langevin equation theory. We describe the structural relaxation as a coupling between local and nonlocal activated process. Meanwhile, the secondary beta process is mainly governed by the nearest-neighbor interactions of a molecule. This assumption implies the beta relaxation acts as a precursor of the alpha relaxation. When external pressure is applied, a small displacement of a molecule is additionally exerted by a pressure-induced mechanical work in the dynamic free energy, which quantifies interactions between a molecule with its nearest neighbors. The local dynamics has more restriction and it induces stronger effects of collective motions on single-molecule dynamics. Thus, the alpha and beta relaxation times are significantly slowed down with increasing compression. We apply this approach to determine the temperature and pressure dependence of the alpha and beta relaxation time for curcumin, glibenclamide, and indomethacin, and compare numerical results with prior experimental studies. Both qualitative and quantitative agreement between theoretical calculations and experiments validate our assumptions and reveal their limitations. Our approach would pave the way for the development of the drug formulation process. 2020-06-18T04:00:35Z 2020-06-18T04:00:35Z 2020 Article Working Paper https://dlib.phenikaa-uni.edu.vn/handle/PNK/401 https://doi.org/10.3390/pharmaceutics12020177 en application/pdf MDPI
institution	Digital Phenikaa
collection	Digital Phenikaa
language	English
topic	compression effects amorphous drugs structural relaxation secondary relaxation glass transition molecular dynamics indomethacin curcumin glibenclamide
spellingShingle	compression effects amorphous drugs structural relaxation secondary relaxation glass transition molecular dynamics indomethacin curcumin glibenclamide Anh D. Phan Katsunori Wakabayashi Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression
description	Compression effects on alpha and beta relaxation process of amorphous drugs are theoretically investigated by developing the elastically collective nonlinear Langevin equation theory. We describe the structural relaxation as a coupling between local and nonlocal activated process. Meanwhile, the secondary beta process is mainly governed by the nearest-neighbor interactions of a molecule. This assumption implies the beta relaxation acts as a precursor of the alpha relaxation. When external pressure is applied, a small displacement of a molecule is additionally exerted by a pressure-induced mechanical work in the dynamic free energy, which quantifies interactions between a molecule with its nearest neighbors. The local dynamics has more restriction and it induces stronger effects of collective motions on single-molecule dynamics. Thus, the alpha and beta relaxation times are significantly slowed down with increasing compression. We apply this approach to determine the temperature and pressure dependence of the alpha and beta relaxation time for curcumin, glibenclamide, and indomethacin, and compare numerical results with prior experimental studies. Both qualitative and quantitative agreement between theoretical calculations and experiments validate our assumptions and reveal their limitations. Our approach would pave the way for the development of the drug formulation process.
format	Article
author	Anh D. Phan Katsunori Wakabayashi
author_facet	Anh D. Phan Katsunori Wakabayashi
author_sort	Anh D. Phan
title	Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression
title_short	Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression
title_full	Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression
title_fullStr	Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression
title_full_unstemmed	Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression
title_sort	theory of structural and secondary relaxation in amorphous drugs under compression
publisher	MDPI
publishDate	2020
url	https://dlib.phenikaa-uni.edu.vn/handle/PNK/401 https://doi.org/10.3390/pharmaceutics12020177
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score	8.887836

Theory of Structural and Secondary Relaxation in Amorphous Drugs under Compression

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