Comparison of two twin-screw extruders for continuous granulation

Abstract A comparison was made between two twin-screw extruders (APV Baker and Leistritz Micro) used for continuous wet granulation. Both extruders had similar screw configurations, based on the length-to-diameter ratio of the screws, existing out of a conveying zone of 20 D, i.e. 20 times the screw diameter and a granulation zone of 4 D. The kneading blocks in the granulation zone were 2.2 and 2.5 D for the Leistritz and APV extruders, respectively. An experimental design was used to investigate the influence of process parameters (total input rate and screw speed) and extruder type on granule and tablet quality. Dicalcium phosphate and α-lactose monohydrate were used as water-insoluble and water-soluble excipients, respectively. For dicalcium phosphate, the amount of fines (