Evaluation and prediction of powder flowability in pharmaceutical tableting

Abstract

The focus of this study is to establish a characterization method determining the powder flowability in context of tableting. At first, flowability of different materials is measured using the ring shear tester, and its prediction from particle size is established. Next, the model die-filling system is presented which is a modified version of previous studies. Using this system, flowability of different materials is measured at varying die speeds. A new curve fit to assess die fill ratio vs die speed is suggested improving predictability, and a novel flowability metric, "Die Fill Index" (DFI), is derived. The DFI is appropriate to describe flowability for most of the tested materials, and sensitivity of a material with respect to tableting speed. A correlation is generated predicting DFI from particle size. Additionally, it is shown that model die filling is the preferable method to assess flowability for tableting compared to ring shear tester.

Assessing Die Filling Using High‐Speed Camera Imaging

“…In comparison to the previously reported model die filling system [2 -9], the following differences, in addition to the ones reported by Hildebrandt et al [11], can be identified. 5 -7, have been taken for the entire die filling process for each and every material (Tab.…”

“…2 and described in detail by Hildebrandt et al [11]. 2 and described in detail by Hildebrandt et al [11].…”

“…Particle size is one of the main powder flow influencing factors in die filling (see above and as shown in [11]) which gave rise to include only this material property in the fit. However, it is very costly to conduct these experiments and they are not a standard method in pharma industries.…”

“…Other particle size data (x 10 , and the particle size distribution factor SPAN [11]) and mathematical correlations have been tested as well but did not improve the goodness of fit. Other particle size data (x 10 , and the particle size distribution factor SPAN [11]) and mathematical correlations have been tested as well but did not improve the goodness of fit.…”

“…Although, Parteck M100 has same chemical composition and a comparable production process as Parteck M200, the differences in powder flow that can be identified during die filling (Figs. 5 and 7) arise most presumably from their particle size difference as all other powder flowability influencing factors (e.g., shape, chemical nature, density [11]) are negligible.…”