A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)

This paper reports the extension to binary propellant/excipient mixtures of the multiphase model of transient internal flow and atomisation in pressurised metered dose inhalers (pMDIs) of Gavtash et al. (2017a-b) for propellant-only flows. The work considers different accounts of the effect of less...

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Main Authors:	Barzin Gavtash, Hendrik Versteeg, Graham Hargrave, Benjamin J. Myatt, David Lewis, Tanya Church, G. Brambilla
Format:	Default Article
Published:	2018
Subjects:	Mechanical engineering not elsewhere classified Pressurized metered dose inhalers (pMDI) Atomization Multiphase flow Multicomponent Phase Doppler anemomentry Numerical simulation Mechanical Engineering not elsewhere classified
Online Access:	https://hdl.handle.net/2134/33450
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id	rr-article-9563054
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spelling	rr-article-95630542018-01-01T00:00:00Z A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI) Barzin Gavtash (3333024) Hendrik Versteeg (1248945) Graham Hargrave (1258908) Benjamin J. Myatt (7210103) David Lewis (245511) Tanya Church (7210106) G. Brambilla (3705427) Mechanical engineering not elsewhere classified Pressurized metered dose inhalers (pMDI) Atomization Multiphase flow Multicomponent Phase Doppler anemomentry Numerical simulation Mechanical Engineering not elsewhere classified This paper reports the extension to binary propellant/excipient mixtures of the multiphase model of transient internal flow and atomisation in pressurised metered dose inhalers (pMDIs) of Gavtash et al. (2017a-b) for propellant-only flows. The work considers different accounts of the effect of less volatile ethanol on the saturated vapour pressure (SVP), viscosity and surface tension of HFA-based pMDI formulations. Representation of the SVP of HFA/ethanol mixtures by Raoult’s law is compared with the empirical model developed by Gavtash et al. (2016) as well as different theoretical mixing rules for surface tension and viscosity. For initial ethanol contents ranging from 0 to 20% by mass, the temperature, pressure and spray velocity were predicted to be almost independent of ethanol concentration when using the empirical SVP model of Gavtash et al. (2016). The predicted aerosol droplet size increases with increasing concentration of ethanol. These model predictions compare favourab ly with phase Doppler anemometry (PDA) measurements of pMDI sprays. Exploration of model predictions with different mixing rules suggest that variations of the dynamic viscosity could result in 0.7 µm droplet size change, and different surface tension models yield around 1.5 µm droplet size change. The findings of this work challenge the view that the increase of droplet size is caused by the low volatility of excipients such as ethanol. Instead, attention is focused on composition-dependent viscosity and surface tension as potential controlling parameters with significant effect on the droplet size of HFA/ethanol sprays. 2018-01-01T00:00:00Z Text Journal contribution 2134/33450 https://figshare.com/articles/journal_contribution/A_model_of_transient_internal_flow_and_atomization_of_propellant_ethanol_mixtures_in_pressurized_metered_dose_inhalers_pMDI_/9563054 CC BY-NC-ND 4.0
institution	Loughborough University
collection	Figshare
topic	Mechanical engineering not elsewhere classified Pressurized metered dose inhalers (pMDI) Atomization Multiphase flow Multicomponent Phase Doppler anemomentry Numerical simulation Mechanical Engineering not elsewhere classified
spellingShingle	Mechanical engineering not elsewhere classified Pressurized metered dose inhalers (pMDI) Atomization Multiphase flow Multicomponent Phase Doppler anemomentry Numerical simulation Mechanical Engineering not elsewhere classified Barzin Gavtash Hendrik Versteeg Graham Hargrave Benjamin J. Myatt David Lewis Tanya Church G. Brambilla A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)
description	This paper reports the extension to binary propellant/excipient mixtures of the multiphase model of transient internal flow and atomisation in pressurised metered dose inhalers (pMDIs) of Gavtash et al. (2017a-b) for propellant-only flows. The work considers different accounts of the effect of less volatile ethanol on the saturated vapour pressure (SVP), viscosity and surface tension of HFA-based pMDI formulations. Representation of the SVP of HFA/ethanol mixtures by Raoult’s law is compared with the empirical model developed by Gavtash et al. (2016) as well as different theoretical mixing rules for surface tension and viscosity. For initial ethanol contents ranging from 0 to 20% by mass, the temperature, pressure and spray velocity were predicted to be almost independent of ethanol concentration when using the empirical SVP model of Gavtash et al. (2016). The predicted aerosol droplet size increases with increasing concentration of ethanol. These model predictions compare favourab ly with phase Doppler anemometry (PDA) measurements of pMDI sprays. Exploration of model predictions with different mixing rules suggest that variations of the dynamic viscosity could result in 0.7 µm droplet size change, and different surface tension models yield around 1.5 µm droplet size change. The findings of this work challenge the view that the increase of droplet size is caused by the low volatility of excipients such as ethanol. Instead, attention is focused on composition-dependent viscosity and surface tension as potential controlling parameters with significant effect on the droplet size of HFA/ethanol sprays.
format	Default Article
author	Barzin Gavtash Hendrik Versteeg Graham Hargrave Benjamin J. Myatt David Lewis Tanya Church G. Brambilla
author_facet	Barzin Gavtash Hendrik Versteeg Graham Hargrave Benjamin J. Myatt David Lewis Tanya Church G. Brambilla
author_sort	Barzin Gavtash (3333024)
title	A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)
title_short	A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)
title_full	A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)
title_fullStr	A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)
title_full_unstemmed	A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)
title_sort	model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pmdi)
publishDate	2018
url	https://hdl.handle.net/2134/33450
_version_	1797733696014385152

A model of transient internal flow and atomization of propellant/ethanol mixtures in pressurized metered dose inhalers (pMDI)

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