Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, Virginia, 23284-3015, USA.
Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia, USA.
AAPS PharmSciTech. 2020 May 25;21(5):157. doi: 10.1208/s12249-020-01667-3.
The objective of this study was to explore different internal flow passages in the patient interface region of a new air-jet-based dry powder inhaler (DPI) in order to minimize device and extrathoracic aerosol depositional losses using computational fluid dynamics (CFD) simulations. The best-performing flow passages were used for oral and nose-to-lung (N2L) aerosol delivery in pediatric extrathoracic airway geometries consistent with a 5-year-old child. Aerosol delivery conditions were based on a previously developed and tested air-jet DPI device and included a base flow rate of 13.3 LPM (delivered from a small ventilation bag) and an inhaled air volume of 750 mL. Initial CFD models of the system clearly established that deposition on either the back of the throat or nasal cannula bifurcation was strongly correlated with the maximum velocity exiting the flow passage. Of all designs tested, the combination of a 3D rod array and rapid expansion of the flow passage side walls was found to dramatically reduce interface and device deposition and improve lung delivery of the aerosol. For oral aerosol administration, the optimal flow passage compared with a base case reduced device, mouthpiece, and mouth-throat deposition efficiencies by factors of 8-, 3-, and 2-fold, respectively. For N2L aerosol administration, the optimal flow pathway compared with a base case reduced device, nasal cannula, and nose-throat deposition by 16-, 6-, and 1.3-fold, respectively. In conclusion, a new patient interface design including a 3D rod array and rapid expansion dramatically improved transmission efficiency of a dry powder aerosol.
本研究旨在探索新型气流射流式干粉吸入器（DPI）患者接口区域的不同内部流道，以便通过计算流体动力学（CFD）模拟最小化装置和胸外气溶胶沉积损失。最佳性能的流道用于儿科胸外气道几何形状的口腔和鼻-肺（N2L）气溶胶输送，符合 5 岁儿童的特征。气溶胶输送条件基于先前开发和测试的气流射流 DPI 装置，包括 13.3 LPM 的基础流速（由小通风袋输送）和 750 mL 的吸入空气量。该系统的初始 CFD 模型清楚地表明，在喉咙后部或鼻插管分叉处的沉积与离开流道的最大速度强烈相关。在所测试的所有设计中，发现 3D 棒阵列和流道侧壁的快速扩张的组合可大大减少接口和装置沉积，并提高气溶胶的肺部输送。对于口腔气溶胶给药，与基础病例相比，最佳流道分别将装置、接口和口咽沉积效率降低了 8 倍、3 倍和 2 倍。对于 N2L 气溶胶给药，与基础病例相比，最佳流路分别将装置、鼻插管和鼻-咽沉积减少了 16 倍、6 倍和 1.3 倍。总之，包括 3D 棒阵列和快速扩张在内的新型患者接口设计极大地提高了干粉气溶胶的传输效率。
