Kondo Tetsuri, Tanigaki Toshimori, Hibino Makoto, Tajiri Sakurako, Horiuchi Shigeto, Maeda Kazunari, Tobe Shunichi, Kamada Riko
Department of Respiratory Medicine, Shonan Fujisawa Tokushukai Hospital, Fujisawa, Japan.
Department of Respiratory Medicine, Tokai University Oiso Hospital, Oiso, Japan.
J Aerosol Med Pulm Drug Deliv. 2023 Aug;36(4):181-188. doi: 10.1089/jamp.2022.0060. Epub 2023 May 22.
A pressurized metered dose inhaler combined with a valved holding chamber (pMDI+VHC) is used to prevent upper airway complications and improve the efficiency of inhaled drug delivery; however, the aerodynamic behavior of the released particles has not been well investigated. This study aimed at clarifying the particle release profiles of a VHC using simplified laser photometry. An inhalation simulator comprised a computer-controlled pump and a valve system that withdrew aerosol from a pMDI+VHC using a jump-up flow profile. A red laser illuminated the particles leaving VHC and evaluated the intensity of the light reflected by the released particles. The data suggested that the output (OPT) from the laser reflection system represented particle concentration rather than particle mass, and the latter was calculated as OPT × instantaneous withdrawn flow (WF). Summation of OPT hyperbolically decreased with flow increment, whereas summation of OPT × instantaneous flow was not influenced by WF strength. Particle release trajectories consisted of three phases, namely increment with a parabolic curve, flat, and decrement with exponential decay phases. The flat phase appeared exclusively at low-flow withdrawal. These particle release profiles suggest the importance of early phase inhalation. The hyperbolic relationship between WF and particle release time revealed the minimal required withdrawal time at an individual withdrawal strength. The particle release mass was calculated as laser photometric output × instantaneous flow. Simulation of the released particles suggested the importance of early phase inhalation and predicted the minimally required withdrawal time from a pMDI+VHC.
一种结合带阀储雾罐的压力定量吸入器（pMDI + VHC）用于预防上呼吸道并发症并提高吸入药物递送的效率；然而，所释放颗粒的空气动力学行为尚未得到充分研究。本研究旨在使用简化激光光度法阐明VHC的颗粒释放曲线。一种吸入模拟器包括一个计算机控制的泵和一个阀门系统，该系统使用跃升气流曲线从pMDI + VHC中抽取气雾剂。一束红色激光照亮离开VHC的颗粒，并评估所释放颗粒反射的光强度。数据表明，激光反射系统的输出（OPT）代表颗粒浓度而非颗粒质量，后者通过OPT×瞬时抽取流量（WF）计算得出。OPT总和随流量增加呈双曲线下降，而OPT×瞬时流量的总和不受WF强度影响。颗粒释放轨迹包括三个阶段，即呈抛物线曲线增加阶段、平稳阶段和呈指数衰减减少阶段。平稳阶段仅在低流量抽取时出现。这些颗粒释放曲线表明了早期吸入阶段的重要性。WF与颗粒释放时间之间的双曲线关系揭示了在单个抽取强度下所需的最短抽取时间。颗粒释放质量通过激光光度输出×瞬时流量计算得出。对所释放颗粒的模拟表明了早期吸入阶段的重要性，并预测了从pMDI + VHC中所需的最短抽取时间。
