CHARACTERIZATION OF PHARMACEUTICAL SOLVATES BY COMBINED THERMOGRAVIMETRIC AND INFRARED-ANALYSIS

The combined physical analytical technique of thermogravimetric and in frared analysis (TG/IR) is described for the investigation of pharmace utical solids. TG/IR provides an unequivocal identification of the vol atile content of a pharmaceutical solid. In the case of pharmaceutical solvates, TG/IR provides identification of the evolved gas from the c rystalline solid. Variable temperature X-ray diffraction and different ial scanning calorimetry techniques provide the required information t o ascertain whether the evolved gas was due to a solvent incorporated into the crystal lattice or physically adsorbed onto the solid. This w ork illustrates three examples of TG/IR as utilized in a multidiscipli nary approach to the physical characterization of pharmaceutical solid s.