10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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The Particle Size Distribution Measurements of Aerosol Generated by Common Inhalers and Nebulisers
ONDREJ MISIK, Frantisek Lizal, Miloslav Belka, Jakub Elcner, Jan Jedelsky, Jan Tuhovcak, Miroslav Jicha, Brno University of Technology
Abstract Number: 328 Working Group: Health Related Aerosols
Abstract The important factor which influences the effect of inhalation treatment is the location of particle deposition in lungs, which directly depends on the size distribution of inhaled particles. [1]
Our aim was to compare various commonly available inhalers using an Aerodynamic Particle Sizer and match the results with data reported by manufacturers or with data acquired by different measurements.
The measurement An Aerodynamic Particle Sizer (APS, TSI 3321, TSI Inc., Shoreview, MN, USA) was used for the measurement. A Fine Particle Fraction (FPF) was evaluated from the acquired particle size distribution. FPF represents the particles within the size range of 1–5 µm, which corresponds to the particles depositing well in lungs. As a second characteristics of the generated particle the count median of aerodynamic diameter (CMAD) has been used. [2]
The aerosol was sucked to the APS using an isokinetic probe and a conductive tubing. Special effort was made to arrange continuous sampling during the measurement of MDIs (metered dose inhalers), however, the manual triggering of the inhalers caused inaccuracies. [2]
Seven devices were measured (InnoSpire® Elegace®, Philips Respironics; Atrovent®, Respimat® SMI Placebo®, Respimat® SMI Spiolto®, Boehringer Ingelheim; Ultibro® Breezhaler®, Novartis; ANORO® Ellipta®, Glaxosmithcline; Brimica® Genuair®, AstraZeneca). In case of measurement of DPIs (dry powder inhalers) it was necessary to simulate patient’s inspiration by a breathing simulator. In this case, the assembly was extremely sensitive to leaks. The leaks would cause an improper simulation of a breathing cycle, and hence a loss of precision. [2]
Results and discussion Several interesting phenomena have been observed on the basis of the acquired data. In case of the nebuliser (InnoSpire® Elegance®, Philips Respironics®, USA) the measured CMAD increased during the measurement, which probably indicates coagulation of particles. The device operated for approximately 2.5 minutes and within this time the value of FPF increased from 60 % to 85 %. The FPF reported by the manufacturer is about 77 % and recommended time for the usage is 6 – 8 minutes. The results obtained for Atrovent® MDI generally correspond to the data measured by Mitchel et al. [3] on the Aerosizer [2]. In case of Respimat, the range for FPF reported by manufacturer should be between 65 – 80 %. Both of measured Respimat formulations fell into this interval. [2] The results acquired with APS generally agree with data reported by manufacturers or with data from measurements reported in literature. The inaccuracies and differences were most likely caused by weaknesses of assembly or by manual operating of the devices. During MDI measurements, the main source of problems was high velocity of the emitted aerosol, in DPI the proper actuation of devices using the breathing simulator. [2]
Acknowledgement The authors would like to acknowledge the financial support provided by the Czech Science Foundation under the grant GA 16–23675S, and the COST-European Cooperation in Science and Technology, Action MP1404: Simulation and pharmaceutical technologies for advanced patient-tailored inhaled medicines (SimInhale).
References 1. W. Hinds, Aerosol technology: properties, behavior, and measurement of airborne particles, 2nd ed. (Wiley, New York, 1999). 2. O. Misik, Inhaler and nebulizers for medical use, bachelor, 2017. 3. J. Mitchell, M. Nagel and Y. Chengà, J. Aerosol Sci. 30, (1999).