Abstract We report a cross-industry study characterizing flow rate-time profiles of equipment used for testing dry-powder inhalers (DPIs). Nine organizations used the same thermal mass flow sensor to record flow rate-time profiles at the inlet of individual participant compendial DPI test systems including either sample collection tubes (SCT), the Andersen 8-stage non-viable impactor (ACI) or the Next Generation Impactor (NGI™) with and without pre-separator (PS). The plan included some tests with a surrogate DPI consisting of one of three inlet orifices chosen to generate a 4-kPa pressure drop at each of the target final flow rates of 30, 60, and 90 l.min−1, simulating the pressure drop typical of high-, medium-, and low-resistance DPIs. When a particular surrogate DPI was present at the inlet, rise times to 90% of these target flow rates (t 90) were shortest at the highest target flow rate, and decreased linearly with decreasing apparatus internal volume, following the order: NGI-PS > NGI > ACI-PS > ACI > SCT. A flow acceleration parameter was also evaluated, expressed as the slope between the rise times when the flow rate attained 20% and 80% of each final steady flow rate (slopet 20/80). Flow acceleration was smallest at the lowest target flow rate, decreasing exponentially with increasing internal volume. Measurements were also made without the surrogate DPI, providing a reference condition with no resistance at the inlet to the apparatus. These flow rate-rise time profiles will be useful for those involved in evaluating equipment for characterizing DPIs and in understanding the behavior of these inhalers in development or commercial production. Copyright © 2020 American Association for Aerosol Research

中文翻译：

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通常用于干粉吸入器 (DPI) 测试的测试设备的流速-时间曲线的跨行业评估：第 1 部分 – 药典仪器

摘要 我们报告了一项跨行业研究，该研究表征了用于测试干粉吸入器 (DPI) 的设备的流速-时间曲线。九个组织使用相同的热质量流量传感器在各个参与者药典 DPI 测试系统的入口处记录流速-时间曲线，包括样品收集管 (SCT)、Andersen 8 级非活性冲击器 (ACI) 或 Next带和不带预分离器 (PS) 的代撞击器 (NGI™)。该计划包括使用替代 DPI 进行的一些测试，该测试由三个入口孔口中的一个组成，以在 30、60 和 90 l.min-1 的每个目标最终流速下产生 4-kPa 压降，模拟压降典型的高、中、低电阻 DPI。当入口处存在特定的替代 DPI 时，达到这些目标流速的 90% (t 90) 的上升时间在最高目标流速下最短，并且随着设备内部体积的减小而线性下降，顺序为：NGI-PS > NGI > ACI-PS > ACI > SCT。还评估了流动加速度参数，表示为当流速达到每个最终稳定流速的 20% 和 80% 时的上升时间之间的斜率（斜率 20/80）。在最低目标流速下流动加速度最小，随着内部体积的增加呈指数下降。测量也是在没有替代 DPI 的情况下进行的，提供了在设备入口处没有阻力的参考条件。这些流速上升时间曲线对于那些参与评估用于表征 DPI 的设备以及了解这些吸入器在开发或商业生产中的行为的人非常有用。版权所有 © 2020 美国气溶胶研究协会