Application of response surface methodology to design optimization in formulation of a typical controlled release system

Through the application of factorial design in an experimental formulation, the role of talc and magnesium stearate as dissolution retardants in matrix type controlled release formulation containing a highly water soluble drug such as dexchlorpheniramine maleate Mas investigated It was found that talc (1-6%, W/W) on its own did not significantly affect matrix hardness or release profiles. Magnesium stearate (1-8%, W/W) exerted a significant exponential decrease on drug release rates and had a weakening effect on tablet hardness. This latter effect was easily counteracted by inclusion of low levels of talc in formulation. The response surface plot of interrelationship between dissolution time (T-50) amounts of magnesium stearate, and talc showed that the retardation in release profile extends in a non-linear fashion over the entire magnesium stearate concentration range. Results also indicate that regardless of the formulation composition there is always a significant interaction effect between talc and magnesium stearate in stabilization of a coherent matrix.