Nose temperature and anticorrelation between recrystallization kinetics and molecular relaxation dynamics in amorphous morniflumate at high pressure
We probe the dielectric response of the supercooled liquid phase of Morniflumate, a drug with anti-inflammatory and antipyretic properties, studying in particular the pressure and temperature dependence of the relaxation dynamics, glass transition temperature Tg, and recrystallization kinetics. Tg i...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/179466 |
| Acceso en línea: | https://hdl.handle.net/2117/179466 https://dx.doi.org/10.1021/acs.molpharmaceut.9b00351 |
| Access Level: | acceso abierto |
| Palabra clave: | Molecular dynamics Crystallization Glassy drug stability Dielectric spectroscopy Secondary relaxation Recrystallization kinetics Optimum crystal growth temperature Cristal·lització Dinàmica molecular Àrees temàtiques de la UPC::Física |
| Sumario: | We probe the dielectric response of the supercooled liquid phase of Morniflumate, a drug with anti-inflammatory and antipyretic properties, studying in particular the pressure and temperature dependence of the relaxation dynamics, glass transition temperature Tg, and recrystallization kinetics. Tg increases by roughly 20 K every 100 MPa at low applied pressure, where the ratio Tg/Tm has a constant value of ~0.8 (Tm = melting point). Liquid Morniflumate displays two dielectric relaxations: the structural a relaxation associated with the collective reorientational motions, which become arrested at Tg, and a secondary relaxation likely corresponding to an intramolecular dynamics. The relaxation times of both processes scale approximately with the inverse reduced temperature Tg/T. Near room temperature and under an applied pressure of 50 MPa, supercooled Morniflumate recrystallizes in a characteristic time of few hours, with an Avrami exponent of 1.15. Under these conditions, the recrystallization rate is a nonmonotonic function of temperature, displaying a maximum at around 298 K, which can be taken to be the optimum crystal growth temperature Tnose. The ß relaxation becomes kinetically frozen at ambient temperature under an applied hydrostatic pressure higher than 320 MPa, suggesting that the Morniflumate glass should be kinetically stable under these conditions. |
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