A review of regime maps for granulation.

Granulation, a size enlargement technique to form agglomerates of primary particles, has proven to be effective in the production of solid dosage forms. Numerous granulation techniques can be applied, such as roll compaction, drum granulation, high shear granulation, twin-screw granulation or fluid-bed granulation. If the fundamental knowledge about the granule growth mechanism, its impacts as well as their extent and proportions on the mechanism is known, a correlation of the input variables with the granule attributes paves the way regarding a granulation process design and prediction of a systems growth behaviour if one or more affecting parameters change. The dimensionless correlation of the main controlling parameters of the process physics is able to confine an operation window within which different regime areas are defined and where the influencing parameters have different implications on the final product. A regime map is created. The usage of dimensionless numbers ensures a reduction of both the experimental workload and the number of parameters that have to be considered. Thus, a scale-independent operation window can be defined. The aim of the review is a critical discussion of proposed regime maps for different granulation processes.