Improving powder flow properties of a cohesive lactose monohydrate powder by intensive mechanical dry coating

Qi Zhou, B Armstrong, Ian Clair Larson, Peter James Stewart, David Alexander Vodden Morton

Research output: Contribution to journalArticleResearchpeer-review

78 Citations (Scopus)


The objective of this study was to improve the cohesive lactose powder flowability. A cohesive lactose monohydrate powder was processed in either a tumbling blender or an intensive mechanical processor with either magnesium stearate or fumed silica. No substantial changes in particle size were detected by laser diffraction following either treatment. The untreated lactose sample exhibited very poor powder flow. Only limited improvements in powder flowability were indicated after the tumbling blending, intensive mechanical processing of the lactose sample with magnesium stearate demonstrated exceptionally large increases in both poured and tapped density as well as notable improvements in all powder flowability indicators examined. Our findings support the use of intensive mechanical processing technique as an effective method to coat cohesive pharmaceutical powders with selected additives, modify the surface nature of the particles, reduce the interparticle cohesive forces and hence improve powder flowability. The subtle differences in powder flow behavior of lactose samples between the untreated and tumbling blended powders with the magnesium stearate were only detected by the powder rheometer using its dynamic mode, indicating its potential advantages over traditional powder flow characterisation approaches.
Original languageEnglish
Pages (from-to)969 - 981
Number of pages13
JournalJournal of Pharmaceutical Sciences
Issue number2
Publication statusPublished - 2010

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