The effect of using a turbulence grid on fluidization of pharmaceutical lactose powder
K. Elserfy1, S. Cheng1, H-K. Chan3, G. Hebbink2, M. Mehta2 & A. Kourmatzis4
1 School of Engineering, Macquarie University, NSW 2109
2 DFE Pharma, Klever Strasse 187, 47568 Goch, Germany
3 Advanced Drug Delivery Group, School of Pharmacy, The University of Sydney, NSW 2006
4 School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006
An experimental platform is presented to investigate the effect of grid-generated turbulence and turbulence decay on the fluidization of pharmaceutical powder for oral inhalation drug delivery. The flow consists of a fully developed channel flow which delivers a well-defined velocity profile over a bed of powder. An in-house laser extinction method has been developed to extract quantitative information on the global powder fluidisation time. Four lactose powders are examined which have a range of mass mean diameters and cohesiveness. Reynolds numbers from approximately 3,383 to 9,000 are examined. The grid location position was changed from being at the powder pocket edge (x=0) to a distance equivalent to approximately 10 times the mesh size (M), representing one of a few quantitative studies to address the role of a regular turbulence grid on the fluidization of pharmaceutical powder in a simple powder pocket geometry. The use of turbulence grids enables evacuation of powder at lower Reynolds numbers and complete evacuation of the powder from the pocket with minimal residue.