Summary
In recent years, industries and governments have been battling against climate change. Greenhouse gases contribute significantly to global warming and so significant worldwide efforts have been made to reduce their use1. Currently, metered dose inhalers (MDIs) use the hydrofluoroalkanes HFA-134a or HFA-227ea as the propellant. Both of these gases have a global warming potential (GWP) over 1000 times greater than CO2. The hydrofluoroolefin, HFO-1234ze(E), has great potential to be the replacement to HFA propellants due to its favorable environmental, physical, and toxicological properties. Given its near-zero GWP and lack of flammability, HFO-1234ze(E) is currently being developed as replacement for HFA-134a and HFA-227ea in MDI applications. HFO-1234ze(E) toxicology studies have been successfully submitted to health authorities across multiple countries in support of ongoing phase 3 clinical trials with anticipated commercial launch in MDIs in 2025. The current paper outlines the comprehensive overview regarding the environmental, flammability, pre-formulation, regulatory and safety profile of HFO-1234ze(E), which includes completion of 2-year carcinogenicity studies in mice and rats. Overall, HFO-1234ze(E) is the only non-flammable, near-zero GWP green propellant enabling companies to successfully transition from HFAs in order to achieve their sustainability goals, while preserving patient health.