Materials Compatibility Considerations for the Transition to Low Global Warming Potential Propellants for Pressurized Metered Dose Inhalers

Abstract

Pressurized metered dose inhalers (pMDI) are a vital therapy for the treatment of lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). In pMDI, the propellants used to deliver the drug to the lungs are hydrofluorocarbons (HFC). However, the current HFCs in use have large global warming potential (GWP). In order to reduce or eliminate the use of propellants with large global warming potential, efforts are underway within the pharmaceutical industry to transition to the use of low GWP propellants in pMDI, while maintaining their effectiveness in treating disease. The current switch from higher GWP propellants mirrors the switch from chlorofluorocarbon (CFC) propellants to HFCs undertaken in the 1990’s, which was driven by ozone depletion concerns. In this paper, the International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS) discusses aspects of the switch to low GWP propellants from the perspective of materials compatibility of pMDI components with low GWP propellants. Leveraging the learnings and advances in pMDI component materials implemented following the switch from CFCs, industry is well positioned to make the change. This paper describes the utility of the low GWP propellants being developed for use in pMDI and the learnings from the previous transition that are being leveraged by industry. The current state of development will be described, including a review of available literature supporting the transition to low GWP propellants.