Search tips
Search criteria 


Logo of aapspharmspringer.comThis journalToc AlertsSubmit OnlineOpen Choice
AAPS PharmSciTech. 2005 September; 6(3): E398–E404.
Published online 2005 October 19. doi:  10.1208/pt060349
PMCID: PMC2750383

Application of powder rheometer to determine powder flow properties and lubrication efficiency of pharmaceutical particulate systems


The objective of this study was to understand the behavior of particulate systems under different conditions of shear dynamics before and after granulation and to investigate the efficiency of powder lubrication. Three drug powders, metronidazole, colloidal bismuth citrate, and tetracycline hydrochloride, were chosen as model drugs representing noncohesive and cohesive powder systems. Each powder was individually granulated with microcrystalline cellulose and 5%PVP as a binder. One portion from each granulation was lubricated with different levels of magnesium stearate for 5 minutes. The powder characterization was performed on the plain powders, nonlubricated and lubricated granules using powder rheometer equipped with a helical blade rotating and moving under experimentally fixed set of parameters. The profiles of interaction during the forcedistance measurements indicate that powder compresses, expands, and shears many times in a test cycle. Test profiles also clearly reveal existence of significant differences between cohesive and noncohesive powders. In all cases lubrication normalized the overall interactive nature of the powder by reducing peaks and valleys as observed from the profiles and reduced the frictional effect. The developed methods are easy to perform and will allow formulation scientists to better understand powder behavior and help in predicting potential impact of processing factors on particulate systems.

Keywords: Powder characterization, powder rheometer, lubrication efficiency, force-distance profile, particulate system

Full Text

The Full Text of this article is available as a PDF (484K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
1. Guerin E, Tchoreloff P, Leclere B, Tanguy D, Deleuil M, Couarraze G. Rheological characterization of pharmaceutical powders using tap testing, shear cell and mercury porosimeter. Int J Pharm. 1999;189:91–103. doi: 10.1016/S0378-5173(99)00243-4. [PubMed] [Cross Ref]
2. Abdullah EC, Geldart D. The use of bulk density measurements as flowability indicators. Powder Technol. 1999;102:151–165. doi: 10.1016/S0032-5910(98)00208-3. [Cross Ref]
3. Lavoie F, Cartilier L, Thibert R. New methods characterizing avalanche behavior to determine powder flow. Pharm Res. 2002;19:887–893. doi: 10.1023/A:1016125420577. [PubMed] [Cross Ref]
4. Bhattachar SN, Hedden DB, Olsofsky AM, Qu X, Hsieh W, Canter KG. Evaluation of the vibratory feeder method for assessment of powder flow properties. Int J Pharm. 2004;269:385–392. doi: 10.1016/j.ijpharm.2003.09.024. [PubMed] [Cross Ref]
5. Orband JLR, Geldart D. Direct measurement of powder cohesion using a torsional device. Powder Technol. 1997;92:25–33. doi: 10.1016/S0032-5910(97)03212-9. [Cross Ref]
6. Dyakowski T, Luke SP, Ostrowski KL, Williams RA. On-line monitoring of dense phase flow using real time dielectric imaging. Powder Technol. 1999;104:287–295. doi: 10.1016/S0032-5910(99)00106-0. [Cross Ref]
7. Weth M, Hofmann M, Kuhn J, Fricke J. Measurement of attractive forces between single aerogel powder particles and the correlation with powder flow. J Non-Cryst Solid. 2001;285:236–243. doi: 10.1016/S0022-3093(01)00460-4. [Cross Ref]
8. Kachrimanis K, Karamyan V, Malamataris S. Artificial neural networks (ANN) and modeling of powder flow. Int J Pharm. 2003;250:13–23. doi: 10.1016/S0378-5173(02)00528-8. [PubMed] [Cross Ref]
9. Cole GC. Powder characteristics for capsule filling. In: Ridgway K, editor. Hard Capsules Development and Technology. London: The Pharmaceutical Press; 1987. pp. 80–86.
10. Podczeck F, Newton JM. Powder and capsule filling properties of lubricated granulated cellulose powder. Eur J Pharm Biopharm. 2000;50:373–377. doi: 10.1016/S0939-6411(00)00100-4. [PubMed] [Cross Ref]
11. Podezeck F. Rheological studies of the physical properties of powders used in capsule filling. Pharm Technol Eur. 1999;11:16–24.
12. Freeman RE. The flowability of powder-an empirical approach. From powder to bulk/International conference on powder and bulk solids handling. London: IMechE HQ; 2000. pp. 545–556.
13. Freeman RE. Predicting flowability and characterizing powders. Pharm Technol Eur. 2004;16(1):41–43.
14. Pillay V, Fassihi R. A new method for dissolution studies of lipidfilled capsules employing Nifedipine as a model drug. Pharm Res. 1999;16:334–338. doi: 10.1023/A:1011959914706. [PubMed] [Cross Ref]
15. Pillay V, Fassihi R. In situ electrolyte interactions in a diskcompressed configuration system for up-curving and constant delivery. J Control Release. 2000;67:55–65. doi: 10.1016/S0168-3659(00)00192-9. [PubMed] [Cross Ref]
16. Durig T, Fassihi R. Guar-based monolithic matrix systems: effect of ionizable and non-ionizable substances and excipients on gel dynamics and release kinetics. J control Release. 2002;80:45–56. doi: 10.1016/S0168-3659(01)00546-6. [PubMed] [Cross Ref]
17. Zulegar S, Fassihi R, Lippold BC. Polymer particle erosion controlling drug release II. Swelling in vestigations to clarify release mechanisms. Int J Pharm. 2002;247:23–37. doi: 10.1016/S0378-5173(02)00362-9. [PubMed] [Cross Ref]
18. Brittain HG. Particle-size distribution II: The problem of sampling powdered solids. Pharm Technol. 2002;26(7):67–73.

Articles from AAPS PharmSciTech are provided here courtesy of American Association of Pharmaceutical Scientists