The effects of feed frame parameters and turret speed on mini-tablet compression.

Die filling is a critical process step during tablet production as it defines the tablet weight. Achieving die fill consistency during production of mini-tablets, tablets with diameters ≤ 6 mm, is considerably more challenging. While die filling in rotary presses had been studied in relation to feed paddle design, paddle speed and turret speed, it is unclear how these process variables could impact mini-tablet production and product properties. In this study, 1.8 and 3 mm mini-tablets were prepared using a rotary press with multiple-tip tooling using different process configurations. Mini-tablet weight variation within and across compaction cycles were determined using data from compression roller displacement and mini-tablet weight. Higher die fill densities were achieved with flat feed wheel paddle and high paddle speed. This was attributed to better granule fluidisation in the feed frame which also increased inter-cycle weight variation and reduced tensile strength. Turret speed did not impact mini-tablet properties significantly. Granule over-lubrication in the feed frame potentially reduced mini-tablet tensile strength during compaction. Number of paddle passes in the die fill region was correlated to mini-tablet die fill performance. Findings from this study could provide better insights into the relationship between process variables and mini-tablet product quality.