HFO-1234ze(E): Propelling Towards Carbon Neutrality

Erik Boldt1, Ryan Hulse1, Barbara Decaire1, Greg Smith1

1Honeywell International, 20 Peabody Street, Buffalo, NY 14210, USA



The effects of climate change have been becoming more apparent each year. Rising global temperatures are significantly affecting ecosystems, resulting in detrimental changes to human health and longevity. There has been a concerted effort to combat the many causes of anthropogenic climate change, including the reduction of carbon and greenhouse gas emissions. Although they only account for a small proportion of global emissions, less than 0.003%, pressurized metered dose inhalers use fluorinated gases with high global warming potentials, exceeding 1000 times that of carbon dioxide.

Industry leaders in respiratory therapy have taken note and begun a push to reduce their carbon emissions by phasing out these potent gases. However, with over 600 million people worldwide suffering from respiratory diseases, a large percentage rely on pressurized metered dose inhalers to manage their symptoms. Keeping these medications readily available while reducing environmental impact is of the utmost importance.

Hydrofluoroolefin-1234ze(E) (HFO-1234ze(E), brand name Solstice® Air, Honeywell) is currently under evaluation and has been adopted as an alternative propellant for pressurized metered dose inhalers. With a near-zero global warming potential, it offers environmental, safety, and regulatory benefits without compromising on performance. HFO-1234ze(E) has been shown to offer similar performance metrics and an excellent safety and tolerability profile in healthy volunteers in a clinical study sponsored by AstraZeneca.


Key Message

Current research and clinical data indicate that HFO-1234ze(E), with a near-zero global warming potential, is a safe and robust alternative propellant for pressurized metered dose inhalers, ensuring these essential medications remain available for patients who need them.