ABSTRACT
A suspension is a particular class or type of dispersion or dispersed system in which the internal or suspended phase is dispersed uniformly by mechanical agitation throughout the external phase. When one or more types of solid particles that constitute the internal phase are pharmaceutically useful and/or physiologically active, the system is known as a pharmaceutical suspension. Martin and Bustamante list three general classes of pharmaceutical suspensions: orally administered; externally applied; and injectable. A suspension is often chosen as pharmaceutical dosage form for drugs insoluble in water and aqueous fluids at the dosage required for administration and when attempts to solubilize the drug would compromise stability and safety. The mean particle diameter and the particle size distributions of suspended insoluble drugs are important considerations in formulating stable pharmaceutical suspensions. The empirical method of producing pharmaceutical suspensions is based on an attempt to prepare a stable deflocculated dispersion of a drug in a suitable suspension vehicle.
