title: Estimation of the fragility index of indomethacin by DSC using the heating and cooling rate dependency of the glass transition.
abstract: In this study we have investigated the features of the glass transition relaxation of indomethacin using Differential Scanning Calorimetry (DSC). The purpose of this work is to provide an estimation of the activation energy at the glass transition temperature, as well as of the fragility index, of amorphous indomethacin from DSC data. To do so, the glass transition temperature region of amorphous indomethacin was characterized in both cooling and heating regimes. The activation energy for structural relaxation (directly related to glass fragility) was estimated from the heating and cooling rate dependence of the location of the DSC profile of the glass transition. The obtained results were similar in the heating and in the cooling modes. The results on the fragility index of indomethacin obtained in the present study, m = 60 in the cooling mode and m = 56 in the heating mode, are compared with other values previously published in the literature.
authors.affiliation: Centro de Química-Física Molecular, Complexo 1, IST, Av. Rovisco Pais, 1049-001 Lisbon, Portugal. mouraramos@ist.utl.pt
authors.forename: Joaquim J Moura
authors.initials: JJ
authors.lastname: Ramos
authors.forename: Raquel
authors.initials: R
authors.lastname: Taveira-Marques
authors.forename: Hermínio P
authors.initials: HP
authors.lastname: Diogo
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods; D003080:Cold Temperature; D005898:Glass / Q000737:chemistry; D006358:Hot Temperature; D007213:Indomethacin / Q000032:analysis / Q000737:chemistry*; D013223:Statistics as Topic; D044366:Transition Temperature
chemical_list: D007213:Indomethacin