Water and Stability of Pharmaceutical Solids

Cherry Auditorium, Kirk Hall

Water has a significant, and usually detrimental, impact on long-term stability and shelf-life of pharmaceutical solids. The presentation overview mechanisms of destabilization of different types of pharmaceuticals, including highly ordered crystalline phases, crystalline mesophases with one- or two-dimensional positional order, and amorphous structures. Role of water in stability of amorphous materials is considered in some details, including water role as a plasticizer and molecular mobility enhancer as well as a reactant in hydrolytic reactions. In addition, impact of water on "solvent" properties of amorphous materials, such as acid-base relationships, is discussed. Finally, recent X-ray and neutron scattering studies of water clusters present in amorphous solids, and the impact of these findings on understanding of water relationships in pharmaceutical solids, are discussed.