Interfacial phenomena are significant factors that affect the adsorption of active ingredients such as: drugs onto solid adjuncts in dosage forms, penetration of molecules through all kinds of membranes, emulsion formation and stability, and the dispersion of insoluble particles in liquid media to form suspensions. Interfacial phenomena are also important in the characterization of materials and reagents during their development, formulation and manufacturing. For example, the biochemical activity, adsorption, disintegration, dissolution and bioavailability of a drug may depend on the surface property of the molecule. The interfacial properties of a surface active agent lining the alveoli of the lungs are responsible for the efficient operation of this organ, just one of many applications to mention. The interface existing between matters in nature are basically categorized into four interactions: liquid/liquid, liquid/vapor (gas), solid/vapor and solid/liquid.