A method for predicting the amount of water required for wet granulation using NIR

The purpose of this study is to optimize the amount of water to be added as a binder solution in wet granulation. In our previous studies, we introduced a method to predict the suitable amount of water added to multi-component formulations by summing corresponding values of the components estimated by an NIR sensor prior to granulation. But in this theory, water added to a formulation is assumed to be evenly distributed to each excipient. To guarantee this theory, we used two-component mixtures as a simplified model to estimate the water distribution to each component using an NIR sensor. In cases in which the volume of water added was comparatively small, water was evenly distributed to each excipient; however, when the water added was increased it was not evenly distributed. To interpret this phenomenon, a new concept was introduced, taking the migration of water between each excipient into consideration. By introducing the concept, it turned out to be possible to predict the suitable amount of water to be added in the two-component model by summing the corresponding values of each component even in a range in which there was an uneven distribution.