Solstice® Air
Solstice® Air is the first ultra-low global warming potential (GWP) medical propellant used in pressurized metered dose inhalers (pMDIs) approved for patient use.
With a GWP of less than 1, Solstice Air reduces the greenhouse gas emissions of the pMDIs by up to 99.9% when compared to current inhaler propellants, making it a commercially viable pMDI propellant to combine environmental responsibility with regulatory readiness.
Solstice Air offers a sustainable, near drop-in alternative to conventional hydrofluoroalkanes (HFAs), requiring minimal changes to the manufacturing process and formulations without compromising device performance. It’s built on advanced, next-generation hydrofluoroolefin (HFO) technology to support the future of respiratory care.
Chemically stable, nonflammable and non-ozone-depleting, Solstice Air represents the future of respiratory drug delivery. Pharmaceutical innovators can now maintain therapeutic performance while meeting global decarbonization and environmental, social and governmental objectives.
Solstice Air helps pharmaceutical companies and manufacturers meet global decarbonization and regulatory goals without compromising therapeutic performance, patient safety or device compatibility.
To learn more about Solstice Air partnerships, case studies and regulatory approvals, click here.
Find answers to the most common techinical, safety and regulatory questions about Solstice Air (HFO-1234ze(E))
HFO-1234ze(E) has a global warming potential (GWP) of ~1, significantly lower than traditional propellants, like HFA-134a (GWP 1300) and HFA-227ea (GWP 3350), per Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Estimated carbon emission for HFO-1234ze(E) is 5-9 g CO₂[DS1] e per dose compared to 9 g (DPI), 20 g (HFA-152a), 263 g (HFA-134a), and 697 g (HFA-227ea).
Yes, under standard conditions (23°C, 50% RH), HFO-1234ze(E) is nonflammable, as confirmed by ASTM E681, EC A11, ISO 10156, and additional tests (ASTM D3605, ignition distance, closed drum). It may show a very narrow flammable range in rare, nonstandard conditions (≥ 30°C, ≥ 50% RH, high-energy ignition source). Controlled manufacturing environments mitigate this risk.
Yes. A 2011 study showed < 5% swelling and comparable mechanical resistance in common elastomers (EPDM, nitrile, chloroprene, butyl, TPE) after four weeks of immersion in HFO-1234ze(E), HFA-134a and HFA-227ea at room temp and 40°C/75% RH.
Yes. Solstice Air has a full toxicology package with carcinogenicity studies in two species. In addition, there have been several phase 1 and 3 clinical trials demonstrating safety and tolerability for use in MDIs. Data is available upon request.
Yes. A DMF is filed with the U.S. Food and Drug Administration and can be referenced for Investigational New Drug (IND), Abbreviated New Drug Application (ANDA) and New Drug Application (NDA) submissions. DMFs are also filed in Japan and China.
Honeywell supplies commercial cGMP-grade HFO-1234ze(E) from its Baton Rouge, LA facility. R&D quantities (e.g., 50 lbs, ½ ton) are available from Buffalo, NY.
Solstice Air Technical Data
Experts have demonstrated how Solstice Air can be safely and effectively used in pMDIs to deliver high-performance respiratory treatment. Request our comprehensive list of scientific resources and clinical studies to learn more about Solstice Air’s performance characteristics, formulation compatibility, safety data and regulatory compliance.
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