Development of HFA-152a as an environmentally sustainable propellant for pressurized metered dose inhalers

While regulations currently do not place restrictions on the use of HFA-134a or HFA-227ea for pressurized metered dose inhalers, they have the potential to adversely impact the supply chain through rationing or loss of industrial product feedstocks used as inputs for medical product manufacturing. Further, individuals and companies are seeking ways to reduce their environmental impacts, with carbon footprints. This provides motivation to adopt alternative propellants for pressurized metered dose inhalers (pMDIs). Yet the interests of the patient must be foremost in any approach to change. In addition, essential criteria for a new propellant include environmental sustainability, safety, functionality and economics. A number of materials have been considered as potential propellants for pMDIs. HFA-152a is under investigation and, to date, has shown an attractive combination of environmental and formulation performance properties.