Pharmaceutical studies on the interactions and some additives between Certain drugs

Colloidal and porous silica are of outstanding importance as carriers in solid, semisolid and liquid dosage forms due to its excellent physicochemical and physiological properties. Adsorption of drugs into their large surface areas has been used for enhancement of dissolution rate and bioavailability of poorly soluble drugs and for uniform distribution of low dosed drugs in single-dose application forms. In addition, silicates has been successfully employed to formulate some drugs in a sustained release dosage form. However, little work has been done to understand the nature of interaction between drugs and silica. In fact the Knowledge of the interactions between drugs and silicas from the molecular piont of view seems to be very important for the achievement of great progress in the application of silica in pharmaceutical prepartions. The work in this thesis involved the study of ”the molecular interaction of several drugs and new types of porous silica, namely Florite R and Florite S, Florite R is mainly composed of calcium silicate, while Florite S is mainly composed of silicon dioxide. These new kinds of silica have unique features such as : good flowability, excellent mouldability and high liquid holding ability.