ABSTRACT
In both hot melt extrusion and extrusion granulation, the constant delivery of the formulation to the extruder is critical to its overall uniform output. This delivery can include a premix of the ingredients or can involve separate deliveries of the active pharmaceutical ingredient (API), polymer, and/or excipients. The selection of the proper bulk solids feeder technology in pharmaceutical extrusion is a critical step in resultant process efficiency and product quality. In the extrusion process, feeders are used in a variety of unit operations, including feeding of the API to a mill or micronizer, batch dispensing of the individual ingredients to the blender for a preblend mix, or feeding individual components to a continuous blender or extruder. Three factors affect volumetric screw feeder accuracy: the consistency of delivered volume per screw revolution, the accuracy of screw speed control, and material density variability.
