Massimo Pasini

The terfenadine/β-cyclodextrin inclusion complex

Terfenatine (TFN) is a very hydrophobic antiallergic drug. It exists in three polymorphic and two solvated forms and is practically insoluble in water. These properties make a pharmaceutical formulation with acceptable biopharmaceutical characteristics difficult to prepare. Inclusion complexation with β-cyclodextrin (βCD) may eliminate such problems. The properties of the TFN/βCD system have been studied in liquid, gaseous and solid phases by1H and13C NMR spectroscopy, powder X-ray diffractometry, differential scanning calorimetry and fast atom bombardment mass spectrometry. The solubility phase diagram was also recorded. In solution and in the gaseous phase the 1∶1 complex prevails, whereas a 1∶2 TFN/βCD complex has been isolated by precipitation from homogeneous solution.