Publication Type Journal Article
Title The Slow Relaxation Dynamics in the Amorphous Pharmaceutical Drugs Cimetidine, Nizatidine, and Famotidine
Authors M. Teresa Viciosa J. J. Moura-Ramos H. P. Diogo
Groups
Journal JOURNAL OF PHARMACEUTICAL SCIENCES
Year 2016
Month December
Volume 105
Number 12
Pages 3573-3584
Abstract The slow molecular mobility in the amorphous solid state of 3 active pharmaceutical drugs (cimetidine, nizatidine, and famotidine) has been studied using differential scanning calorimetry and the 2 dielectric-related techniques of dielectric relaxation spectroscopy and thermally stimulated depolarization currents. The glass-forming ability, the glass stability, and the tendency for crystallization from the equilibrium melt were investigated by differential scanning calorimetry, which also provided the characterization of the main relaxation of the 3 glass formers. The chemical instability of famotidine at the melting temperature and above it prevented the preparation of the amorphous for dielectric studies. In contrast, for cimetidine and nizatidine, the dielectric study yielded the main kinetic features of the a relaxation and of the secondary relaxations. According to the obtained results, nizatidine displays the higher fragility index of the 3 studied glass-forming drugs. The thermally stimulated depolarization current technique has proved useful to identify the Johari-Goldstein relaxation and to measure tau(beta JG) in the amorphous solid state, that is, in a frequency range which is not easily accessible by dielectric relaxation spectroscopy. (C) 2016 American Pharmacists Association (R). Published by Elsevier Inc. All rights reserved.
DOI http://dx.doi.org/10.1016/j.xphs.2016.08.019
ISBN
Publisher WILEY-BLACKWELL
Book Title
ISSN 0022-3549
EISSN 1520-6017
Conference Name
Bibtex ID ISI:000389027800012
Observations
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