Enthalpy of solution of terfenadine in ethanol/water mixtures

Abstract The enthalpy of solution of terfenadine in ethanol/water mixtures, 0±20.5 wt.% of water was determined by calorimetry. A Sudden increase of 1±2 kJ mol À1 in the enthalpy at a concentration value around 0.01 mol kg À1 is observed. This step in the enthalpy is interpreted as due to solute n-mer aggregates formation. The solubility of terfenadine in the cosolvent systems used in the calorimetric studies was determined.