As sustainability pressures drive innovation in pressurised Metered Dose Inhalers (pMDIs), the regulatory landscape must shift to accommodate new low carbon technology. In a sector that has already undergone one major transition in recent decades, how are regulators, drug developers and contract development and manufacturing organisations (CDMOs) responding? Sarah Bunyan, Head of Regulatory Affairs at Bespak, explores key considerations in this space.

Q: Beginning in the 1990s, chlorofluorocarbon (CFC) propellants were transitioned to hydrofluoroalkanes (HFAs) due to concern over depletion of the ozone layer. How have pMDI regulations around propellants changed since then, and what has prompted these changes?
A: The previous shift from CFCs to HFAs was relatively slow, taking place over a 20-year period from the mid 1990s. pMDIs were already crucial devices in the inhalation space at this time, and it was clear they needed to be updated to avoid the damage to the ozone layer caused by their CFC propellants. Unfortunately, the HFA propellants that were phased in were not without their own environmental impacts. In fact, they still produce emissions today with a higher Global Warming Potential (GWP) than carbon dioxide. More than 30 years after the previous transition, environmental awareness has brought this issue into focus and it has become clear that we need more environmentally acceptable options.

There are several factors adding pressure to adopt new propellants. Firstly, whilst pMDIs are only responsible for around 3% of total healthcare-related emissions in the UK, they are seen as a relatively quick fix for the industry. As a result, there has been a push towards prescribing propellant-free options such as Dry Powder Inhalers (DPIs) for patients; however, the costs and time implications for managing a switch can be substantial.