HFO MDI

HFO MDI refers to a metered dose inhaler (MDI) formulation that uses hydrofluoroolefin (HFO), specifically HFO-1234ze(E) (trans-1,3,3,3-tetrafluoropropene), as the propellant instead of traditional hydrofluoroalkane (HFA) propellants. Unlike conventional MDIs that deliver active pharmaceutical ingredients for conditions like asthma or COPD, the current clinical studies of "HFO MDI" are evaluating the safety and effects of the propellant itself—without any added drug—on mucociliary clearance and bronchospasm in healthy volunteers and asthma patients[1][3][5]. The primary motivation for developing HFO-based MDIs is environmental; HFO-1234ze(E) has a near-zero global warming potential compared to HFAs[7][9][10]. Nonclinical data support its safety at exposure levels far exceeding those expected in patients[7]. The device is being developed by AstraZeneca as part of efforts to transition respiratory inhalers toward more sustainable formulations.

Other names

Hydrofluoroolefin Metered Dose InhalerHFO propellant MDIHFO-1234ze(E) MDI