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AAPS PharmSciTech. 2000 September; 1(3): 20–30.
Published online 2000 June 21. doi:  10.1208/pt010318
PMCID: PMC2750346

Composite method to quantify powder flow as a screening method in early tablet or capsule formulation development


The flow properties of typial tablet and capsule formulation excipients, active compounds, and representative formulation blends were tested with current and novel flow measurement techniques to identify a reliable bench test to quantify powder flow as a screening method in early tablet and capsule formulation development. Test methods employed were vibrating spatula, critical orifice, angle of repose, compressibility index, and avalanching analysis. Powder flow results from each method were compiled in a database, sorted, and compared. An empirical composite index was established and powder flow was ranked in accordance with formulator experience. Principal components analyses of the angle of repose, percent compressibility, and critical orifice of the powder materials were also performed. The first principal component accounted for 72.8% of data variability; scores associated with this principal component score can serve as an index of flowability. Data generated from vibrating spatula and avalanching methods were not reproducible and were inconsistent with formulator experience and cited vendor references for flow. Improvements of test instruments and further studies are necessary for better assessment of these approaches.

Keywords: Principal components analysis, Critical orifice, Powder flow, Avalanching, Angle of repose, Compressibility index

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
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