Case Study: Optimization of a Liposomal Formulation with Respect to Tissue Damage

It is recognized that the development of injectable dispersed systems requires the pharmaceutical scientist to have an understanding of the physicochemical properties, biopharmaceutical properties, particle and rheological characterization, and release properties of these formulations. These issues are well discussed and outlined by other contributors to this volume. However, a consideration in the development of an injectable dispersed system, that most often may be overlooked, is the interaction of this formulation or components with the tissues at the site of injection and the extent to which a formulation may cause pain upon injection. Even the best formulated products, with respect to the ideal physicochemical, biopharmaceutical and release properties, could be found to have limited application if shown in animal or clinical studies to cause tissue damage and=or pain following injection.