Coates Matthew S, Chan Hak-Kim, Fletcher David F, Raper Judy A
Department of Chemical Engineering, University of Sydney, Sydney, NSW 2006, Australia.
J Pharm Sci. 2006 Jun;95(6):1382-92. doi: 10.1002/jps.20603.
This study investigates the effect of air inlet size on (i) the flowfield generated in a dry powder inhaler, and (ii) the device-specific resistance, and the subsequent effect on powder deagglomeration. Computational fluid dynamics (CFD) analysis was used to simulate the flowfield generated in an Aerolizer with different air inlet sizes at 30, 45, and 60 l/min. Dispersion performance of the modified inhalers was measured using mannitol powder and a multistage liquid impinger at the same flow rates. The air inlet size had a varying effect on powder dispersion depending on the flow rate. At low flow rates (30 and 45 l/min), reducing the air inlet size increased the inhaler dispersion performance by increasing the flow turbulence and particle impaction velocities above their critical levels for maximal powder dispersion. At 60 l/min, reducing the air inlet size reduced the inhaler dispersion performance by releasing a large amount of powder from the device before the turbulence levels and particle impaction velocities could be fully developed. The results demonstrate that the maximal inhaler dispersion performance can be predicted if details of the device flowfield are known.
（i）干粉吸入器中产生的流场，以及（ii）设备特定阻力，以及对粉末解聚的后续影响。采用计算流体动力学（CFD）分析来模拟在30、45和60升/分钟不同进气口尺寸下Aerolizer中产生的流场。使用甘露醇粉末和多级液体撞击器在相同流速下测量改良吸入器的分散性能。进气口尺寸对粉末分散的影响因流速而异。在低流速（30和45升/分钟）下，减小进气口尺寸通过增加流动湍流和颗粒撞击速度使其高于最大粉末分散的临界水平，从而提高了吸入器的分散性能。在60升/分钟时，减小进气口尺寸在湍流水平和颗粒撞击速度充分发展之前从设备中释放出大量粉末，从而降低了吸入器的分散性能。结果表明，如果知道设备流场的详细信息，就可以预测最大吸入器分散性能。
