Abstract
The molecular details and phase transition of drug crystal were studied by thermal analysis, combination of other measurements and simultaneous measurements of X-ray diffraction (XRD) and DTA systems. In the crystalline state, methosorbinil have been shown to exist in two polymorphic crystalline forms, α- and β-form crystals by DSC and infrared spectroscopy. Transformation from the β- to α-form was observed at various heating rates, which were enhanced by the presence of a small amount of α-form crystals. Cefclidin has been shown to exist in three pseudopolymorphic crystalline forms, α-, β- and γ-form crystals by X-ray diffractometry. The relationship between the pseudopolymorphic crystal forms of cefclidin and water content was studied by X-ray diffractometry, moisture analysis and vacuum freeze drying experiments. The phase transition of crystalline cefclidin clearly indicated the effect of water content on dehydration. In studying phase transition of pseudopolymorphism of E4031 and E3060, XRD-DTA system technique which describe characterization of the phase transition of pseudopolymorphism has been developed. The present study clarified the phase behavior of pharmaceuticals with thermodynamics, and spectroscopic, and newly XRD-DTA system technique.
