Feeding Technology and Material Handling for Pharmaceutical Extrusion
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.