title: The slow relaxation dynamics in active pharmaceutical ingredients studied by DSC and TSDC: Voriconazole, miconazole and itraconazole.
abstract: The slow molecular mobility of three active pharmaceutical drugs (voriconazole, miconazole and itraconazole) has been studied by differential scanning calorimetry (DSC) and thermally stimulated depolarization currents (TSDC). This study yielded the main kinetic features of the secondary relaxations and of the main (glass transition) relaxation, in particular their distribution of relaxation times. The dynamic fragility of the three glass formers was determined from DSC data (using two different procedures) and from TSDC data. According to our results voriconazole behaves as a relatively strong liquid, while miconazole is moderately fragile and itraconazole is a very fragile liquid. There are no studies in this area published in the literature relating to voriconazole. Also not available in the literature is a slow mobility study by dielectric relaxation spectroscopy in the amorphous miconazole. Apart from that, the results obtained are in reasonable agreement with published works using different experimental techniques.
authors.affiliation: CQFM-Centro de Química-Física Molecular and IN-Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal. Electronic address: mouraramos@tecnico.ulisboa.pt.
authors.forename: Joaquim J Moura
authors.initials: JJ
authors.lastname: Ramos
authors.affiliation: CQE-Centro de Química Estrutural, Complexo I, IST, Universidade de Lisboa, 1049-001 Lisboa, Portugal. Electronic address: hdiogo@tecnico.ulisboa.pt.
authors.forename: Hermínio P
authors.initials: HP
authors.lastname: Diogo
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D017964:Itraconazole / Q000737:chemistry*; D008825:Miconazole / Q000737:chemistry*; D044366:Transition Temperature; D065819:Voriconazole / Q000737:chemistry*
chemical_list: D000935:Antifungal Agents; D017964:Itraconazole; D008825:Miconazole; D065819:Voriconazole
keywords: Amorphous pharmaceuticals; Dynamic fragility; Glass transition; Molecular mobility; Relaxation time