title: Diclofenac salts. III. Alkaline and earth alkaline salts.
abstract: Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.
authors.affiliation: Istituto di Scienze Chimiche, Università di Bologna, Bologna, Italy. adamo.fini@unibo.it
authors.forename: Adamo
authors.initials: A
authors.lastname: Fini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Fazio
authors.forename: Francesca
authors.initials: F
authors.lastname: Rosetti
authors.forename: M
authors.initials: M
authors.lastname: Angeles Holgado
authors.forename: Ana
authors.initials: A
authors.lastname: Iruín
authors.forename: Josefa
authors.initials: J
authors.lastname: Alvarez-Fuentes
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D003890:Desiccation; D004008:Diclofenac / Q000737:chemistry*; D007700:Kinetics; D008672:Metals, Alkali / Q000737:chemistry*; D008673:Metals, Alkaline Earth / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012492:Salts / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties; D013696:Temperature; D013818:Thermogravimetry; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D008672:Metals, Alkali; D008673:Metals, Alkaline Earth; D012492:Salts; D014867:Water; D004008:Diclofenac