Characterization of a pharmaceutical wet granulation process in a V-type low shear granulator

Wet granulation is a process that has been difficult to fully characterize because it is a rapidly proceeding operation rife with variables to control. Several machines are used for wet granulation, but the low shear rotating granulators, with an agitator bar, lack the basic research into the granulation process that other granulator types enjoy. These low shear machines have yet to be characterized in terms of how key input variables influence key response variables.A Results show that the growth process is a rapid operation that requires low amounts of binder liquid and produces granules of uniform apparent density when typical pharmaceutical formulation constituents are used. These results are in contrast to results in other granulators that show a substantially greater liquid requirement and wide differences in apparent density with similar formulations.The energy profile in this granulator reveals two distinct process periods differentiated by the magnitude of the torque range in each period. These periods are related to the homogeneity of the batch and can be easily used as an indicator of endpoint. The absolute value of the torque input remains relatively constant throughout the wet granulation process in this granulator further confirming that this granulator is sensing the homogeneity of the mass and not the cohesiveness of the mass. Energy profiles in other granulators commonly show continuous increases in torque input specifically because their growth mechanisms rely on the increasing cohesiveness of the mass.The low shear granulator in this study combines the liquid addition and energy input functions into a device called the intensifier bar, resulting in a highly efficient distribution of binder liquid. This mechanism yields favorable properties that are dissimilar to properties in other granulators.