title: Recent developments in the experimental investigations of relaxations in pharmaceuticals by dielectric techniques at ambient and elevated pressure.
abstract: In recent years, there is a growing interest in improving the physicochemical stability of amorphous pharmaceutical solids due to their very promising applications to manufacture medicines characterized by a better water solubility, and consequently by a higher dissolution rate than those of their crystalline counterparts. In this review article, we show that the molecular mobility investigated both in the supercooled liquid and glassy states is the crucial factor required to understand molecular mechanisms that govern the physical stability of amorphous drugs. We demonstrate that pharmaceuticals can be thoroughly examined by means of the broadband dielectric spectroscopy, which is a very useful experimental technique to explore different relaxation processes and crystallization kinetics as well. Such studies conducted in the wide temperature and pressure ranges provide data needed in searching correlations between properties of molecular dynamics and crystallization process, which are aimed at developing effective and efficient methods for stabilizing amorphous drugs.
authors.affiliation: Institute of Physics, University of Silesia, ul, Uniwersytecka 4, 40-007 Katowice, Poland; Silesian Center for Education and Interdisciplinary Research, ul, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Grzybowska
authors.affiliation: Dipartimento di Fisica, Universita ̀ di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy; CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Capaccioli
authors.affiliation: Institute of Physics, University of Silesia, ul, Uniwersytecka 4, 40-007 Katowice, Poland; Silesian Center for Education and Interdisciplinary Research, ul, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland. Electronic address: marian.paluch@us.edu.pl.
authors.forename: Marian
authors.initials: M
authors.lastname: Paluch
mesh_terms: D003460:Crystallization; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D004364:Pharmaceutical Preparations; D012995:Solubility
chemical_list: D004364:Pharmaceutical Preparations
keywords: Amorphous drugs; Broadband dielectric spectroscopy; Crystallization; Dielectric relaxations; Elevated pressure; Molecular mobility; Physical stability