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Is the Climate Right for a New pMDI Propellant?

Pritchard JN.

Respiratory Drug Delivery 2022. Volume , 2022: 1-12.

Abstract:

The emissive use of hydrofluorocarbons (HFCs) as propellants in pressurized metered dose inhalers (pMDIs) is regulated under the Kigali Amendment to the Montreal protocol. It is only one of many uses of F-gases impacted by the phase-down, and as such would not appear to be greatly impacted by the phase-down targets, at least for the next 15 years. However, pressures to reduce carbon footprints, together with the expected increase in cost of medical grade propellant in the Western world may demand a re-evaluation of treatment regimes. For any change to occur, it must be both clinically and economically feasible. Many patients can use dry powder inhalers (DPIs) successfully, and for most classes of drugs, there will be little change in prescription costs. However, not all patients can use dry powder inhalers (DPIs), notably the very young, very old and those undergoing an acute exacerbation. Reliever medication presents a particular challenge, as DPIs are not recommended, and there is every possibility that prices will have to rise by 2025. In many markets, this may make this life-saving medicine unaffordable.

Thus, there is a clear need for alternatives to the current reliever pMDIs that are both affordable and environmentally friendly. The most promising option in the near-term is to reformulate pMDIs with either HFC 152a or hydrofluoroolefin (HFO) 1234ze(E). Not only will this ensure continuity of affordable care, but there are also sound commercial reasons. Three companies have so far made this commitment, and there is promise that we will see pMDIs containing low Global Warming Potential (GWP) propellants on the market by 2025.