Process control in a high shear mixer-granulator using wet mass consistency: The effect of formulation variables

This work investigates the relationships between the wet mass consistency/v iscosity of samples prepared in a mixer-granulator and physical properties of the dry granules produced from the wet mass; namely, size distribution, bulk density (Hausner ratio), friability, and flow avalanching behavior. Th e correlation between the consistency of the wet mass and the downstream dr y granule properties confirms that consistency is the key parameter to cont rol in wet granulation by mechanical agitation. Variations in the formulati on affect the dimensionless power relationship of the mixer-granulator cons idered; that is, the equivalence between wet mass consistency and mixer net power consumption, which is actually the parameter used to monitor the wet granulation process. The same variations in formulation also affect the re lationships between wet mass consistency and dry granule properties.