Granulation Process Modeling

The following sections develop in detail some of the important aspects of granulation process modeling, through the use of population balances and alternative approaches. 

Extent of Noninertial Growth Growth by coalescence in granulation processes may be modeled by the population balance. (See the... 

The phase composition of glycine crystal forms during the drying step of a wet granulation process has been studied, and a model developed for the phase conversion reactions [88], X-ray powder diffraction was used for qualitative analysis, and near-infrared spectroscopy for quantitative analysis. It was shown that when glycine was wet granulated with microcrystalline cellulose, the more rapidly the granulation... 

The authors would like to acknowledge that the section dealing with population balance modeling of granulation processes is an abbreviated version of material prepared by Dr. J. D. Litster, University of Queensland, for a joint short course given by Dr. B. J. Ennis and Dr. J. D. Litster. 

Gereg and Capolla developed process parameters determined by a model laboratory bench scale Carver press, model C (Carver Inc. Savannah, Georgia, U.S.A.), which were translated to production scale compactor parameters (6). Their study provided a method to predict whether a material is suitable for roller compaction. Their study objectives were to characterize properties of the material to identify process parameters suitable to achieve the necessary particle size and density using the dry granulation process and then translate laboratory information to a production scale roller compactor. Actually, information developed from a Carver press was correlated and scaled-up to a production scale Fitzpatrick roller compactor. Model IR 520 (Fitzpatrick Co., Elmhurst, Illinois, U.S.A.) The compactor produced very similar powder granule characteristics as the Carver press. Various lactose materials, available as lactose monohydrate or spray dried lactose monohydrate, were used as the model compounds. Results indicated that a parametric correlation could be made between the laboratory bench Carver press and the production scale compactor, and that many process parameters can be transferred directly. 

In the fluid-bed granulation process, moisture control is the key parameter that needs to be controlled. Faure et al. (133) have used process control for scale-up of a fluidized bed process. They used infra-red probes to monitor moisture. As there are normally large numbers of inter-related variables, they used computerized techniques for process control, such as fuzzy logic, neural networks, and models based on experimental techniques. 

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