Pharmaceutical Surface Science Research Group, Department of Pharmacy and Pharmacology, University of Bath, Bath, BA2 7AY, UK.
Pfizer Ltd, Discovery Park House, Sandwich, Kent, CT13 9NJ, UK.
Pharm Res. 2018 Nov 26;36(1):15. doi: 10.1007/s11095-018-2544-9.
To measure the charge to mass (Q/M) ratios of the impactor stage masses (ISM) from commercial Flixotide™ 250 μg Evohaler, containing fluticasone propionate (FP), Serevent™ 25 μg Evohaler, containing salmeterol xinafoate (SX), and a combination Seretide™ 250/25 μg (FP/SX) Evohaler metered dose inhalers (MDIs). Measurements were performed with a purpose built bipolar charge measurement apparatus (bp-NGI) based on an electrostatic precipitator, which was directly connected below Stage 2 of a Next Generation Impactor (NGI).
Five successive shots of the respective MDIs were actuated through the bp-NGI. The whole ISM doses were electrostatically precipitated to determine their negative, positive and net Q/m ratios.
The ISM doses collected in the bp-NGI were shown to be equivalent to those collected in a standard NGI. FP particles, actuated from Flixotide™ and Seretide™ MDIs, exhibited greater quantities of negatively charged particles than positive. However, the Q/m ratios of the positively charged particles were greater in magnitude. SX particles from Serevent™ exhibited a greater quantity of positively charged particles whereas SX aerosol particles from Seretide™ exhibited a greater quantity of negatively charged particles. The Q/m ratio of the negatively charged SX particles in Serevent™ was greater in magnitude than the positively charged particles.
The bp-NGI was used to quantify the bipolar Q/m ratios of aerosol particles collected from the ISMs of commercial MDI products. The positive charge recorded for each of the three MDIs may have been enhanced by the presence of charged ice crystals formed from the propellant during the aerosolisation process.
测量来自商业 Flixotide™ 250μg 干粉吸入器（含丙酸氟替卡松，FP）、Serevent™ 25μg 干粉吸入器（含沙美特罗昔萘酸酯，SX）和 Seretide™ 250/25μg（FP/SX）干粉吸入器（MDI）的撞击器阶段质量（ISM）的荷质比（Q/M）。使用基于静电沉淀器的专用双极电荷测量仪（bp-NGI）进行测量，该仪器直接连接在下一级 Next Generation Impactor（NGI）的下方。
通过 bp-NGI 激活各 MDI 的连续五次喷射。将整个 ISM 剂量静电沉淀以确定其负电荷、正电荷和净 Q/m 比。
证明 bp-NGI 收集的 ISM 剂量与标准 NGI 收集的剂量相当。从 Flixotide™ 和 Seretide™ MDI 中喷射出的 FP 颗粒表现出比正电荷更多的带负电荷的颗粒。然而，正电荷颗粒的 Q/m 比的绝对值更大。Serevent™ 中的 SX 颗粒表现出更多的正电荷颗粒，而 Seretide™ 中的 SX 气溶胶颗粒表现出更多的负电荷颗粒。Serevent™ 中带负电荷的 SX 颗粒的 Q/m 比的绝对值大于带正电荷的颗粒。
bp-NGI 用于定量测量从商业 MDI 产品的 ISM 收集的气溶胶颗粒的双极 Q/m 比。三个 MDI 记录的正电荷可能是由于推进剂在气溶胶化过程中形成的带电冰晶而增强的。
