ABSTRACT
This chapter discusses the principles that are at work in the field of suspensions, their classification, methods of preparation, and routes to stabilization. Suspensions are defined operationally as a class of materials in which one phase, a solid, is dispersed in a second phase, generally a liquid. This represents the most common system that is of importance to the pharmaceutical or formulation scientist. A suspension or dispersion is a system that generally consists of two phases of matter, although the number of components can be higher. Depending on the state of each phase, one can have a wide series of possibilities. Many suspended materials, especially those in liquids, might have spherical particles, as in emulsions and latices; others can have irregular shapes. Solids that are used to promote the stabilization of suspensions are termed suspending agents.
