In this work, the Discrete Element Method (DEM) is used to simulate the dispersion process of Active Pharmaceutical Ingredients (API) after a wall collision in dry powders inhaler used for lung delivery. Any fluid dynamic effects are neglected in this analysis at the moment. A three-dimensional model is implemented with one carrier particle (diameter 100 μm) and 882 drug particles (diameter 5 μm). The effect of the impact velocity (varied between 1 and 20 m s⁻¹), angle of impact (between 5° and 90°) and the carrier rotation (±100,000 rad s⁻¹) are investigated for both elastic and sticky walls. The dispersion process shows a preferential area of drug detachment located in the southern hemisphere of the carrier. The angle of impact with the highest dispersion is 90° for the velocities over 9 m s⁻¹ and between 30° and 45° for lower velocities. The rotation of the carrier before the impact, on the other hand, for velocities higher than 7 m s⁻¹, plays a little role on the dispersion performance. The DEM results are finally “distilled” into a simplified analytic model that could be introduced as a sub-scale model in Euler/Lagrange CFD calculations linking fluid dynamics with the detachment probability of APIs in the inhaler.

在这项工作中，离散元素方法（DEM）用于模拟活性药物成分（API）在用于肺部输送的干粉吸入器中发生壁碰撞后的分散过程。目前，在此分析中忽略了任何流体动力学效应。使用一个载体颗粒（直径100μm）和882个药物颗粒（直径5μm）实现三维模型。撞击速度（在1到20 m s ^-1之间变化），撞击角度（在5°到90°之间）和载具旋转（±100,000 rad s ^{-1）的影响}）同时针对弹性壁和粘性壁进行了研究。分散过程显示了位于载体南半球的药物分离的优先区域。对于9 m​​ s ^-1以上的速度，具有最大分散度的冲击角为90°，对于较低的速度，冲击角为30°至45°。另一方面，对于高于7 m s ^-1的速度，冲击之前载体的旋转对分散性能的影响很小。最后，将DEM结果“蒸馏”为简化的分析模型，该模型可以作为Euler / Lagrange CFD计算中的子尺度模型引入，该模型将流体动力学与吸入器中API的分离可能性联系起来。