Summary

The widely used current propellants in MDIs (metered dose inhaler) such as HFA 134a and HFA 227 will be subject to a phase down agreement recently signed at Kigali as an amendment to the Montreal Protocol. In an effort to reduce GWP (global warming potential) of medical propellants, HFAs (hydrofluoroalkane) such as HFA 152a are being investigated as replacements. Among the different leachables from the valve, formaldehyde is a critical one because of its toxicity. This study looks at formaldehyde leachables from various HFA MDIs (different plastics evaluated) during storage. Results show that measured levels of leachables after 12 months storage were found to be well within the acceptable toxicity limits. This study demonstrates that from a leachables perspective, it is possible in future to develop equivalent MDI products when moving from HFA 134a to HFA 152a propellant, which has a significantly lower GWP. 

Key message

This study demonstrates that from a formaldehyde leachables perspective, it is possible in future to develop equivalent MDI products when moving from HFA 134a propellant to HFA 152a, which has a significantly lower GWP.