Surface Measurement Systems Limited specialises in the development of instrumental techniques for materials research, and in particular for the prediction of the solid phase interactions between drugs and excipients. The quantification of these interactions allows for a direct prediction of product performance and processing behavior. The underlying principles involve the ability to study the effects of gases and vapours on powders and solids under isothermal conditions using sensitive gravimetric or chromatographic techniques. DVS (Dynamic Vapour Sorption) vapour sorption gravimetric analysis makes use of ambient gas flow conditions for undertaking water or organic vapour adsorption experiments on solid state materials. Inverse Gas Chromatography (iGC) is a unique instrument for powder characterization that provides for the understanding of even more subtle characteristics relating to surface energetics, acid-base properties, reversible and irreversible chemisorption, and much more.