Benjamin Myatt1 & Hossain Chizari1
1 Kindeva Drug Delivery, Charnwood Campus, Loughborough, UK
Summary
The pharmaceutical industry is switching to low global warming potential (GWP) propellants HFA152a or HFO1234ze(E) to reduce the carbon footprint of pressurised metered dose inhalers (pMDIs). The physicochemical properties of these propellants play a critical role in governing the atomisation and plume evolution processes and consequently product performance. The velocity of a spray plume as it exits a pMDI plays a critical role in governing atomised droplet size and is highly dependent on propellant properties. Further downstream, differences in velocity of the spray plume and inhaled co-flow can lead to mixing induced turbulent diffusion and differences in oropharyngeal deposition.
Measurements of pMDI plume velocities of HFA134a, HFA227ea, HFA152a and HFO1234ze(E) propellants emitted from a Kindeva pMDI actuator showed broadly similar velocity profiles both in trend and magnitude through the plume centreline, a vertical plane 25 mm from the actuator mouthpiece and temporally in the centre of the plume at the same distance.