Comparative studies of powder flow predictions using milligrams of powder for identifying powder flow issues

Tong Deng, Vivek Garg, Laura Pereira Diaz, Daniel Markl, Cameron Brown, Alastair Florence, Michael S.A. Bradley

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
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Characterising powder flowability can be challenging when sample quantity is insufficient for a conventional shear cell test, especially in the pharmaceutical industry, where the cost of the active pharmaceutical ingredient (API) used is expensive at an early stage in the drug product development. A previous study demonstrated that powder flowability could be predicted based on powder physical properties and cohesiveness using a small quantity of powder samples (50 mg), but it remained an open question regarding the accuracy of the prediction compared to that measured using industry-standard shear cell testers and its potential to substitute the existing testers. In this study, 16 pharmaceutical powders were selected for a detailed comparative study of the predictive model. The flowability of the powders was predicted using a Bond number and given consolidation stresses, σ , coupled with the model, where the Bond number represents powder cohesiveness. Compared to the measurements using a Powder Flow Tester (Brookfield) and an FT4 (Freeman Technology) Powder Rheometer shear cell tester, the results showed a good agreement between the predictions and the measurements (15 g) if the available amount of sample is small.
Original languageEnglish
Article number122309
Number of pages11
JournalInternational Journal of Pharmaceutics
Early online date18 Oct 2022
Publication statusPublished - 25 Nov 2022


  • small quantity of samples
  • pharmaceutical powders
  • flowability
  • shear cell tests
  • cohesiveness and bond number


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