There is a growing recognition of the need for a thorough understanding of the solid state properties of pharmaceuticals. A complex interplay exists between both the active pharmaceutical ingredients' and excipients' physical and chemical properties and the related unit operations. One important unit operation is wet granulation where the physical characteristics of a powder are optimized for tablet compression. During wet granulation the powder is exposed to solvent, shear and changes in temperature. These conditions make wet granulation likely to induce phase transitions in the solid state. These phase transitions may have a great impact on the quality and properties of the final pharmaceutical product.

In this study the solid state of an active pharmaceutical ingredient during wet granulation is investigated. An elucidation of the physicochemical phenomena taking place during processing is approached by process analytical technologies and off-line testing using near-infrared spectroscopy, Raman spectroscopy, infrared spectroscopy, x-ray powder diffraction, thermal methods and multivariate data analysis.