Formulation of insoluble drugs. Study of pharmaceutical suspensions by response surface methodology

The preformulation of insoluble drugs, sulfadiazine and aluminium hydroxyde , were studied in order to achieve a suspension with desirable requirements . The objective of the formulator is to avoid the irreversible aggregation called "caking", and to obtain a suspension with an airy, large volume sedi ment easily redispersible and with suitable rheological properties. An expe rimental design useful to determine optimal properties is a Central Composi te Design. The surfactant, thickener and electrolyte at different proportio ns are the 3 factors studied. This strategy allows to point on the main sig nificant effect and to determine the concentrations of each product leading to optimal properties of the suspensions.