Department of Pharmacy, China Pharmaceutical University, Nanjing, People's Republic of China.
J Aerosol Med Pulm Drug Deliv. 2012 Oct;25(5):265-79. doi: 10.1089/jamp.2011.0908. Epub 2012 Jan 26.
The performance of dry powder aerosol delivery systems depends not only on the powder formulation but also on the dry powder inhalers (DPIs). Effects of turbulence, grid, mouthpiece, inlet size, air flow, and capsule on the DPIs performance have been investigated previously. Considering powder dispersion in DPIs is a time-dependent process, the powder residence time in DPIs is supposed to have a great impact on DPIs efficiency. This study sought to investigate the effect of powder residence time on the performance of a commercial DPI Aerolizer(®).
A standard Aerolizer(®) (SD) and five modified devices (MD1, MD2, MD3, MD4, and MD5) were employed for this research. Computational fluid dynamics analysis was used to calculate the flow field and the powder residence time in these devices. Recombinant human interleukin-2 inhalation powders and a twin impinger were used for the deposition experiment.
The powder mean residence time in the secondary atomization zone of the devices was increased from 0 ms for SD to 0.33, 0.96, 1.42, 1.76, and 2.14 ms for MD1, MD2, MD3, MD4, and MD5, respectively. At a flow rate of 60 L/min, with an increase in the powder residence time in these devices, a significant gradual and increasing trend in the powder respirable fraction was observed from 29.1%± 1.1% (MD1) to 32.6% ± 2.2% (MD2), 37.1% ± 1.1% (MD3), and 43.7% ± 2.1% (MD4). There was no significant difference in the powder respirable fraction between SD and MD1 or between MD4 and MD5.
Within a certain range, increasing the powder residence time could improve the performance of Aerolizer(®) by increasing the powder-air interaction time (the main reason) and increasing the powder-device compaction (the secondary reason). Combination of high turbulence level and sufficient powder residence time could further improve the device performance.
干粉气溶胶输送系统的性能不仅取决于粉末配方，还取决于干粉吸入器（DPI）。先前已经研究了湍流、格栅、吸嘴、入口尺寸、气流和胶囊对 DPI 性能的影响。考虑到粉末在 DPI 中的分散是一个时间相关的过程，因此粉末在 DPI 中的驻留时间应该对 DPI 的效率有很大的影响。本研究旨在研究粉末驻留时间对商业 DPI Aerolizer(®)性能的影响。
使用标准 Aerolizer(®)（SD）和五台改装设备（MD1、MD2、MD3、MD4 和 MD5）进行这项研究。计算流体动力学分析用于计算这些设备中的流场和粉末驻留时间。重组人白细胞介素-2 吸入粉末和双撞击器用于沉积实验。
设备二次雾化区的粉末平均驻留时间从 0 ms（SD）增加到 0.33、0.96、1.42、1.76 和 2.14 ms（MD1、MD2、MD3、MD4 和 MD5）。在 60 L/min 的流速下，随着这些设备中粉末驻留时间的增加，粉末可吸入分数呈显著的逐渐增加趋势，从 29.1%±1.1%（MD1）增加到 32.6%±2.2%（MD2）、37.1%±1.1%（MD3）和 43.7%±2.1%（MD4）。SD 和 MD1 或 MD4 和 MD5 之间的粉末可吸入分数没有显著差异。
在一定范围内，通过增加粉末与空气的相互作用时间（主要原因）和增加粉末与设备的压实程度（次要原因），增加粉末驻留时间可以提高 Aerolizer(®)的性能。高湍流水平和足够的粉末驻留时间的组合可以进一步提高设备性能。
