Continuous granulation with a twin-screw extruder: impact of material throughput.

Agglomeration behavior of a twin-screw extruder at different material throughputs was investigated. Water insoluble dicalcium phosphate and the binder povidone were agglomerated with demineralized water with five different screw configurations using conveying-, kneading- or combing mixer elements. Increasing material throughput mainly had an effect on the particle size of granules. Due to a higher filling degree of the barrel, the particle size was higher at increased material throughput. Granule porosity was generally influenced by screw element type. With a higher element dispersivity granule porosity and friability decreased. Compression of the different granule batches led to comparable tablet properties. A simple scale up in order to increase batch size can be realized by increasing either production time at given material throughput or material throughput.