Comparison of different flowability tests for powders for inhalation
Författare
Summary, in English
A series of placebo powders for inhalation was characterized regarding bulk density and powder flowability using different techniques. The powders were of the ordered mixture type and were prepared by mixing a pharmaceutical carrier grade of lactose with different fractions of intermediate sized and fine (i.e., micronized) lactose. A modified Hausner Ratio was obtained by measurement of the poured and the compressed bulk densities. Other tests investigated were the angle of repose, the avalanching behaviour using the AeroFlow, and the yield strength using the Uniaxial tester. Furthermore, the relation between ordered mixture composition and flowability was examined. Of the methods investigated, the modified Hausner Ratio discriminates well between the investigated powders and seems to have the widest measuring range. It was also found that the poured and compressed bulk densities provide information about the packing of the particles in the powders. A good correlation was obtained between the modified Hausner Ratio and the angle of repose. The AeroFlow was suitable for powders with a low percentage of fine particles, but could not discriminate between the more cohesive powders. The Uniaxial tester, on the other hand, seems to be better suited for more cohesive powders. Regarding the powder composition, addition of micronized particles has a strong influence on the flowability of ordered mixtures, while intermediate sized particles have little impact on the powder flow. (C) 2004 Elsevier B.V. All rights reserved.
Avdelning/ar
Publiceringsår
2004
Språk
Engelska
Sidor
206-213
Publikation/Tidskrift/Serie
Powder Technology
Volym
146
Issue
3
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Chemical Engineering
Nyckelord
- AeroFlow
- angle of repose
- flowability
- hausner ratio
- ordered mixture
- uniaxial tester
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0032-5910