Saturated Vapor pressure of HFA152a-ethanol and HFO1234ze(E)-ethanol binary mixtures

Swetha Vutlapalli¹, Lingzhe Rao¹, Ben Myatt ², Phil Cocks ², Paul Young ^3,4, Damon Honnery ¹,
Daniel Duke¹

¹Laboratory for Turbulence Research in Aerospace and Combustion, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia

² Kindeva Drug Delivery, Charnwood Campus, 10 Bakewell Road, Loughborough, United Kingdom, LE11 5RB

³ Respiratory Technology, Woolcock Institute of Medical Research, Glebe, Sydney, NSW 2037, Australia

⁴Department of Marketing, Macquarie Business school, Macquarie University, Sydney, NSW 2109, Australia

Summary

Hydrofluoroalkane propellants HFA134a and HFA227ea are being phased down under the Kigali amendment due to their high global warming potential. Propellants HFA152a and HFO1234ze(E) have been proposed as potential alternatives for pressurised metered dose inhalers (pMDIs). Knowledge of the fundamental thermodynamic properties of these alternative propellants is essential to predict and optimise device performance. The vapor pressure of low-GWP propellant binary mixtures with ethanol for use in solution formulations are presently not available in the literature. In this paper, the saturated vapor pressures of HFA152a and HFO1234ze(E) have been measured using a constant-volume technique. For temperatures below 45°C the relative deviations of vapor pressures of HFA152a and HFO1234ze(E) are below 5% and 3.5% as compared with REFPROP10.0, respectively. We show the vapor pressure dependency on ethanol cosolvent concentration for HFA152a and HFO1234ze(E) at a concentration of 8% w/w.

Key Message

The effect of ethanol concentration on saturated vapor pressures (SVP) of propellants HFA152a and HFO1234ze(E) was measured using a constant-volume technique. Experimental measurements are necessary to accurately model the SVP of propellant/cosolvent binary mixtures, particularly at high cosolvent concentrations.