Abstract

Particles and droplets produced from pharmaceutical inhaler devices are naturally charged. Previous in silico and in vitro studies have shown that the levels of these electrostatic charges may potentially affect deposition in the airways but this has not been confirmed in vivo. Human lung scintigraphic studies using radiolabelled particles with controlled charges would provide crucial data on locating the deposition sites with respect to the particle charge level. An aerosol charging rig has been developed for this purpose. ^99mTc-radiolabelled droplets from an Aerogen® Solo vibrating mesh nebuliser were charged by induction and then dried to yield positively charged particles. Particles with near-neutral charges were produced at an induction voltage of -0.4 kV, while those with 10-4,000 elementary charges per particle were generated at -4.5kV, depending on the particle size. The number of elementary charges per particle generally decreased with radioactivity, especially for solutions at 400 and 800 MBq/mL. This was attributed to the indirect ionising effect of the gamma radiation in the air, which produced bipolar ions that neutralised the initially charged particles. Radioactivity at 100 MBq/mL was found to be optimal in generating the highest particle charges that could potentially affect in vivo deposition in the lungs. The aerosol charging rig is suitable for use in human scintigraphy studies which we will conduct in the near future.

摘要

从药物吸入器装置产生的颗粒和液滴自然带电。先前的计算机和体外研究表明，这些静电荷的水平可能会影响气道中的沉积，但尚未在体内得到证实。使用带有可控电荷的放射性标记颗粒的人肺闪烁显像研究将提供关于相对于颗粒电荷水平定位沉积位点的关键数据。为此目的，已经开发了一种气溶胶充电装置。^99m来自Aerogen®Solo振动筛网雾化器的Tc放射状液滴通过感应带电，然后干燥以产生带正电的颗粒。在-0.4 kV的感应电压下产生具有中性电荷的粒子，而根据粒子大小，在-4.5kV时产生每个粒子具有10-4,000个基本电荷的粒子。每个粒子的基本电荷数量通常随放射性而降低，尤其是对于400和800 MBq / mL的溶液。这归因于空气中伽马射线的间接电离作用，该作用会产生双极性离子，从而中和最初带电的粒子。发现100 MBq / mL的放射性最适合产生可能对体内有潜在影响的最高粒子电荷沉积在肺中。气溶胶充电装置适用于人类闪烁显像研究，我们将在不久的将来进行这项研究。