Semisolid drug release with

The key parameter for any drug product is its efficacy as demonstrated in controlled clinical trials. The time and expense associated with such trials make them unsuitable as routine quality control methods. Therefore, in vitro surrogate tests are often used to assure that product quality and performance are maintained over time and in the presence of change. A variety of physical and chemical tests commonly performed on semisolid products and their components (e.g., solubility, particle size and crystalline form of the active component, viscosity, and homogeneity of the product) have historically provided reasonable evidence of consistent performance. More recently, in vitro release testing has shown promise as a means to comprehensively assure consistent delivery of the active component(s) from semisolid products. 

The low melting point of stearic acid makes it ideal as a dispersive agent for the production of soaps, shampoos, detergents and shaving creams. They are added to these products melted and allowed to cool down at room temperature with a gentle stirring to recrystallize and form a semisolid and stable structure. Further, due to its hydrophobic properties and the ability to form hard compacts has been used for controlled release of some drugs. 

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