The transition from high Global Warming Potential (GWP) propellants such as HFA134a to low-GWP alternatives such as HFA152a and HFO1234ze(E) in pressurised metered dose inhalers (pMDIs) poses challenges for inhaled pharmaceutical product development.

Changes in the chemicophysical properties of products formulated with low-GWP propellants such as density and viscosity will alter product performance, impacting in-vitro bioequivalence metrics. This study investigates those differences using equivalent pMDI hardware and formulations.

In this paper, we’ve compiled the largest-yet database of high-resolution plume geometry and aerodynamic particle size distributions for a generic becomethasone dipropionate solution formulation with various co-solvent concentrations. With a sufficiently large, high-resolution dataset, small variations in the repeatability and stability of the sprays produced by different propellants become evident, and this helps explain why deposition and drug delivery varies.