ABSTRACT
Preformulation may be described as a stage of development during which the physico-chemical properties of a drug substance are characterized. Some commonly evaluated param eters include solubility, stability, partitioning, dissolution behavior and solid state properties including crystal forms/polymorphs, water sorption behav iors, surface properties, particle size, and particle shape. A complete understanding of these physicochemical properties is essential for the development of a robust form u lation having optimal performance. Detailed reviews of pharm aceutical preformula tion have been published (Fiese and Hagen 1986; Wells 1988; Ravin and Radebough 1990). Compounds that have limited solubility (typically < 0.1-1 mg/mL depending on the potency of compounds) in water and in comm on pharm aceutical solvents present unusual challenges. Although all the general principles of preformulation apply, there are certain preformulation aspects that are unique to insoluble com pounds. These aspects need to be considered to ensure the successful development of formulations for these agents.
