Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA.
Pharm Res. 2013 Jun;30(6):1608-27. doi: 10.1007/s11095-013-1001-z. Epub 2013 Mar 8.
To employ in vitro experiments combined with computational fluid dynamics (CFD) analysis to determine which aerodynamic factors were most responsible for deaggregating carrier-free powders to form micrometer and submicrometer aerosols from a capsule-based platform.
Eight airflow passages were evaluated for deaggregation of the aerosol including a standard constricted tube, impaction surface, 2D mesh, inward radial jets, and newly proposed 3D grids and rod arrays. CFD simulations were implemented to evaluate existing and new aerodynamic factors for deaggregation and in vitro experiments were used to evaluate performance of each inhaler.
For the carrier-free formulation considered, turbulence was determined to be the primary deaggregation mechanism. A strong quantitative correlation was established between the mass median diameter (MMD) and newly proposed non-dimensional specific dissipation (NDSD) factor, which accounts for turbulent energy, inverse of the turbulent length scale, and exposure time. A 3D rod array design with unidirectional elements maximized NDSD and produced the best deaggregation with MMD<1 μm.
The new NDSD parameter can be used to develop highly effective dry powder inhalers like the 3D rod array that can efficiently produce submicrometer aerosols for next-generation respiratory drug delivery applications.
采用体外实验与计算流体动力学（CFD）分析相结合的方法，确定哪些空气动力学因素是从基于胶囊的平台将无载体粉末解聚形成微米和亚微米气溶胶的主要原因。
评估了 8 种气流通道对气溶胶的解聚作用，包括标准收缩管、冲击面、2D 网格、内径向射流以及新提出的 3D 网格和棒阵列。实施了 CFD 模拟以评估用于解聚的现有和新空气动力学因素，并进行了体外实验以评估每个吸入器的性能。
对于所考虑的无载体配方，确定湍流是主要的解聚机制。质量中值直径（MMD）与新提出的无量纲比耗散（NDSD）因子之间建立了很强的定量相关性，该因子考虑了湍流能量、湍流长度尺度的倒数和暴露时间。具有单向元件的 3D 棒阵列设计最大限度地提高了 NDSD，并产生了最佳的解聚作用，MMD<1μm。
新的 NDSD 参数可用于开发高效的干粉吸入器，如 3D 棒阵列，可有效产生亚微米气溶胶，用于下一代呼吸药物输送应用。
