CALORIMETRIC STUDY OF POLYMORPHIC FORMS OF TERFENADINE

Terfenadine polymorphic forms have been prepared by crystallization fr om ethanol and methanol solutions. The two polymorphs were studied by differential scanning calorimetry (DSC) and thermogravimetry (TG) in a temperature range between 233 and 443 K. From DSC data, structural di fferences between both forms were pointed out. Enthalpies for solution processes of the polymorphs in ethanol and in methanol were determine d. Differences between both solid forms as well as between the solvent behaviour are well noted from the standard solution enthalpy values a nd from the variation of the enthalpy with concentration.