Current Edition

Under Pressure: Finding a More Sustainable Future for pMDIs

The transition away from the use of ozone-damaging chlorofluorocarbon (CFC) gases has been one of the major environmental achievements of modern times. Today, hindsight affords us the ability to see how this transition enabled the Earth’s protective ozone layer to heal itself over several decades. An unintended consequence, however, was that the withdrawal of CFCs (Chlorofluorocarbons) ushered in greater use of hydrofluorocarbons, known as F-gases, which introduced their own environmental challenges.

While this family of gases might not pose a risk to the atmospheric ozone layer, they were found to contribute to the greenhouse effect. Compared with carbon dioxide (CO2 ), F-gases have a far higher global warming potential (GWP), based on attributes including infrared radiation absorption and atmospheric lifetime. These characteristics mean F-gases are now also subject to phasing down, impacting a variety of processes and applications where they currently play an essential role.1 In medicine, the use of F-gases is widespread across the globe, with HFC134a and HFC-227ea relied upon as safe and effective propellants within inhalation devices, helping millions of patients manage respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). As the negative environmental impact of these gases becomes more understood, there are implications for every stakeholder in the chain, from device manufacturers and pharmaceutical companies to healthcare professionals (HCPs) and patients. The phasing down of F-gases is already well underway, with global efforts falling in line with the Montreal Protocol of the Vienna Convention on Substances that Deplete the Ozone Layer. The Montreal Protocol has provided a framework for safeguarding the ozone layer since it went into effect in 1989 to define the transition away from CFCs.2 This framework was expanded on January 1 2019, through the Kigali Amendment, which binds all 198 signatories to also take action to reduce the production and use of F-gases, including the HFCs used in medical devices. Of all territories across the world, Europe has historically implemented the most stringent targets for HFC reduction. On April 5, 2022, The European Commission set out proposals for two new regulations that would strengthen F-gas legislation and pave the way for a series of changes to accelerate the phasing down process. In announcing the proposals, Frans Timmermans, Executive Vice-President for the European Green Deal, said that while the EU’s current ambitious policies have been successful, “science urges us to go further and faster now”.3

Currently, F-gases account for 2.5% of total greenhouse gas emissions across Europe. The European Commission (EC) said the proposals to accelerate their phasing down would contribute to reducing these emissions by at least 55% by 2030 and support the continent’s overarching plan to be climate-neutral by 2050. In the United States, the world’s largest market for pressurised metered dose inhalers (pMDIs), the phase-down programme is scheduled to follow behind Europe through the American Innovation and Manufacturing Act, which came into effect in December 2020. While pMDIs are encompassed within ‘set-aside’ allocations to ease the transition in the region, these are only in place for a period of five years and the US is expected to achieve a phasedown level of 15% by 2035. Other territories across the rest of the world, including India and countries across the Middle East, are expected to follow behind the US for a period of around 15 years. Although these robust environmental targets are fixed in place, less certainty surrounds the knock-on effects of meeting them. Of primary concern here are patients, whose ongoing needs must be met in terms of consistent access to relief and prevention medication – something that can only be achieved through the transition either to alternative inhalation devices with lower GWP, such as dry powder inhalers (DPIs) or to pMDIs using lower GWP propellants. While it would be hoped that such a transition would follow some of the precedent set by the move away from CFCs, it is clear that the phasing down of F-gases must overcome a different set of complex hurdles to ensure device and drug are optimised in a way that satisfies a patient need.