Prediction of sorption isotherms is valuable for accelerating product development and understanding product stability. In this paper, two aspects of this goal are addressed; i) previous work has been extended in estimating the isotherm of granular mixtures from a combination of individual component isotherms and ii) for a simplified set of formulations, a model of the sorption isotherm of the spray dried component is constructed using a response surface methodology. Understanding was gained into varying mixture component levels, as well as developing a more accurate method for the prediction of sorption isotherms using the available techniques. Polynomial fits of sorption isotherms for spray dried powders using the formulation data show a higher level of moisture sorption than observed experimentally. The additivity principle can also be used in the prediction of this type of isotherm.
