Powder flow and mixing in different tablet press feed frames

Abstract

Tablets can be manufactured using a rotary tablet press, which consists of a feed frame followed by the compression and compaction of the powder and subsequent ejection of the tablets. From Quality by Design (QbD) perspectives the feed frame plays a critical role and effects products critical quality attributes (CQAs). Thus optimizing this stage is of huge interest. It is preferable to achieve narrow residence time distributions of the powder in the feed frames as well as homogeneous tablets with respect to their height, weight and tensile strength. In the present study three design approaches of feed frames are simulated using the Discrete Element Method (DEM). We investigate the influence of operational input parameters (i.e., rotational rates) on the behaviour of a free flowing and a cohesive material. The detailed simulation data allows us to compare the mentioned setups in terms of residence times, tablet masses and occurring deviations. Therefore, we are able to determine the optimal feed frame and process settings for both free-flowing and cohesive powders.