On control of particle size distribution in granulation using high-shear mixers

The control of mean granule size and of size distribution is a major issue in granulation processes that utilise mechanical high-shear mixers. Fundamental mechanisms that lead to poor reproducibility are discussed. A review is made of techniques that can be applied to make the process more robust. Binders can be selected that react during the granulation process so as to reduce the binder concentration and/or increase the binder viscosity. There is potential to improve the design of the granulator to give better control of mean size and narrower size distributions. A critical review is made of the use of the mixer power/torque and mixer work for process control.