Insights into the role of tooling characteristics on compressibility evolution in non-flat faced tablets

The robustness of tablet manufacturability largely depends on compressibility behavior of a powder. The compressibility assessment is traditionally conducted on cylindrical flat-faced compacts in contrast to the fact that marketed tablets are majorly produced using non-flat faced or shaped toolings. The present work demonstrates the feasibility of quantifying average compressibility on shaped toolings through a proof-of-concept study by investigating the central band portion and the entire volume of the tablet, which led to several notable findings. Firstly, the yield stress (deformability) was found independent of type of tooling for a given powder in the in-die condition, but for the same tooling it conversely spanned over a wide range in the out-die condition due to characteristic elastic recovery. Secondly, the yield stress parameter correlated with the change in band volume of the shaped tablet with applied compaction pressure, thereby establishing an orthogonal approach to assess compressibility on non-flat faced toolings. The study emphasizes that tooling characteristics may affect compressibility and tablet robustness of a same powder, which should be practiced cautiously in drug product manufacturing.