Local dynamics of pharmaceutical powder fluidization using high speed long distance microscopy and particle image velocimetry

• Published in: Experimental thermal and fluid science Vol. 124; p. 110367
• Main Authors: Elserfy, K., Cheng, S., Chan, H-K., Kourmatzis, A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.2021; Elsevier Science Ltd
• Subjects: Advanced imaging techniques; Aerodynamics; Air flow; Channel flow; Diameters; Drug carriers; Drug delivery; Dry powder inhalers; Dynamics; Flow velocity; Fluid dynamics; Fluid flow; Fluidization; Fluidizing; High speed; Image processing; Inhalers; Lactose; Lactose carriers; Microscopy; Particle image velocimetry; Particle size distribution; Pharmaceutical carriers; Pharmaceuticals; Powder; Size distribution; Turbulent flow; Two-phase flow; Velocity; Lactose carriers; Dry powder inhalers; Pharmaceutical carriers; Two-phase flow; Advanced imaging techniques
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2021.110367

•Advanced imaging techniques were used to analyse cohesive powder dynamics.•Powder particles with larger median diameters travel at slower velocities.•Particles velocity distribution span closely followed their size distribution span.•Velocity fluctuation versus Stokes number was independent of spatial location. The local dynamics of fluidized pharmaceutical carrier powders in a turbulent channel flow was studied using particle image velocimetry (PIV) and High-speed, long-distance microscopy (HS-LDM). Four different lactose powders which have been used as a drug carrier in dry powder inhalers were used in this study. These powders have median powder particle diameters ranging between 61 and 121 µm. Air flow velocities ranging between 13.3 m/s and 66.7 m/s were examined. In addition, the effect of grid blockage ratio (ranging from ~25% to ~40% of the area of channel cross-section) was also investigated. Results show that the high-speed, long-distance microscopy (HS-LDM) technique was able to capture the mean velocity of the particles, and the results corresponded well with the PIV measurements. Results from the high-speed, long-distance microscopy (HS-LDM) method also demonstrate that the span of particle velocity closely follows that of the particle size distribution both for cohesive and non-cohesive powders. This study contributes towards an improved understanding of pharmaceutical carrier dynamics in turbulent channel flows and demonstrates how advanced image processing can be used to capture local particle dynamics.