THERMAL-ANALYSIS OF SPRAY-DRIED PRODUCTS

The ability to alter and control such properties as particle shape, particle size and size distribution, bulk density, porosity, moisture content, flowability, stability, dispersability and friability has led to the increasing use over the last fifty years, of spray drying methods in the manufacture of pharmaceutical dosage forms. However, in addition to the above changes, alterations may also occur in the energy of the spray dried solid components ranging from the disordering of the crystal lattice, the formation of polymorphic and/or pseudopolymorphic forms, the elimination of crystallinity to complex formation. These changes can have far reaching effects on the biopharmaceutical properties and stability of the dosage forms. In this paper reports of such changes occurring in pharmaceutical systems are reviewed and in particular the use of thermal analytical methods to both qualitatively and quantitatively evaluate the occurrence of these solid state modifications.