Influence of rheological behavior of lactose powders on the weight consistency of tablets – Scientific poster

The 12th APV PBP World Meeting took place from 28 – 31 March 2022 in Rotterdam. There was a poster section at the event where really interesting scientific posters were presented. Therefore we asked the presenting scientists if we could share their work in addition online with the Pharma Excipients community.

As many scientists send us their posters, we showed more than 10 posters of the PBP Poster Session and will continue with more.

We continue our poster series with a poster from Aurélien Neveu, Pauline Janssen, Filip Francqui from Granutools and DFE Pharma:
(click on the poster to enlarge it)

Download the poster as PDF here: Poster_PBP2022_granutools

Introduction

Lactose is one of the most widely used excipients in the pharmaceutical industry. There are many reasons for its popularity, such as the fact that lactose is largely inert, relatively inexpensive, safe, many different grades are available, and it has a long history of usage in successful formulations world-wide. For direct compression processes like tableting, lactose excipients can be used as a filler-binder to provide bulk density, compaction and flow to the formulation. Good flow of a pharmaceutical formulation is critical to produce uniform dosage forms. In this study, the rheological properties of lactose powders have been investigated with the rotating drum method (GranuDrum) and correlated with the actual consistency of flow achieved in a tableting system. The investigation of powder flowability at different drum rotating speeds gives useful information on the evolution of powder processability at a higher shear rate. Indeed, with classical characterization method like the angle of repose, the stress state at which the powder is tested is far from what the powder experiments in the tableting machine. In this study, we demonstrate the importance of the powder rheology to get useful insights that allow relevant prediction of the powder processability.

Powder rheology evaluation

• Rotating drum: GranuDrum2 (Granutools, Awans, Belgium)
• Rotating speeds: 2 to 60 rpm
• Cohesive index based on temporal flow fluctuations

Conclusions

In this study, the rheology of two lactose powders has been investigated with a rotating drum method and correlated with the mass variability of produced tablets. The two powders exhibit different rheological behavior: a shear-thickening and a shear-thinning, leading to an inversion of flowability classification at high stress state. The inversion of the flowability classification predicted by the GranuDrum has also been observed in the tableting machine. Indeed, the shear-thinning properties of SuperTab® 21AN leads to an increase of flowability at high agitator speeds and consequently to an increase of tablets mass. These results demonstrate the importance of taking into account the rheological properties of the powder in order to get a relevant prediction of the tableting performance. Furthermore, this highlights the necessity to use a powder characterization method able to mimic the stress state at which the powder will be submitted during its processing.

Authors

Aurélien Neveu 1, Pauline Janssen 2, Filip Francqui 1
1 Granutools, Rue Jean-Lambert Defrêne, 107, 4340 Awans, Belgium, [email protected]
2 DFE Pharma GmbH & Co. KG, Kleverstrasse 187, P.O. Box 20 21 20, 47568 Goch, Germany