Alternative to pMDI? Reduced environmental impact of a reusable soft mist inhaler

Introduction Pressurised metered-dose inhalers (pMDIs) use a hydrofluoroalkane (HFA) propellant, a greenhouse gas with a high global warming potential. Soft mist inhalers (Respimat) are propellant-free and potentially reusable, reducing their environmental impact.

Aims Compare product carbon footprints (PCFs) of disposable Respimat and HFA pMDI devices and assess any environmental impact of a reusable Respimat device supplied with 3 or 6 months of refills.

Methods Whole life-cycle PCFs of tiotropium bromide (Spiriva) Respimat, ipratropium bromide/fenoterol hydrobromide (Berodual) Respimat, Berodual HFA pMDI and ipratropium bromide (Atrovent) HFA pMDI were assessed. Data were collected from relevant supply chain members using customised data collection email templates. PCFs were calculated according to the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5).

Results pMDI PCFs are ˜20 times greater than disposable propellant-free Respimat PCFs (˜98% due to HFA release during use and end-of-life phases). Electricity and thermal energy use in a disposable Respimat device assembly adds more to the PCF than cartridge assembly: 0.38 vs 0.08 kg CO2eq. Therefore, developing a reusable Respimat device has potential to further reduce PCF. Indeed, assessment of a reusable Respimat shows a further reduction in PCF by 57% for a 3 month refill and 71% for a 6 month refill, vs the 1 month disposable Respimat.

Conclusions Respimat not only addresses many practical limitations of pMDIs but also has a considerably lower environmental impact than HFA pMDIs. Development of a reusable option decreases impact even further, providing significant environmental improvements.