Polymorphic and thermodynamic study of indomethacin

Indomethacin is known to exhibit polymorphism. As a consequence the various forms have different Solubilities and may have different bioavailabilities. This Study has been carried out with the following techniques: calorimetry, differential scanning calorimetry (DSC), thermogravimetric analysis (TG), X-ray diffraction and thermomicroscopy. Two solid forms have been prepared and studied: their melting temperature and their enthalpy of fusion are determined. The heat capacity and heat content were measured vs. the temperature for these two solid forms and for the liquid phase. This is fundamental for the determination of the stable form. More of this, with a view to study phase diagrams of indomethacin with another compound (solvent or not), the knowledge of the C-p of the various forms is necessary for calculation of the liquidus curve, this allows to minimize the number of experiments.