Performance of Pressurized Metered‐Dose Inhalers at Extreme Temperature Conditions

The performance of pressurized metered‐dose inhalers (pMDIs) under a variety of temperature conditions was investigated. The effects of both inhaler temperature and ambient temperature were considered. The inhaler temperature ranged from −13.0°C to 41.7°C and the ambient temperature ranged from −12.0°C to 41.7°C. The in vitro lung dose was measured for four widely available pMDIs: AiromirTM, QVARTM, Symbicort®, and Ventolin®. The in vitro lung dose through an Alberta Idealized Throat was measured by gravimetric assay, which was verified by UV spectroscopic assay. A decrease in the in vitro lung dose was observed for all evaluated pMDIs when ambient temperature and device temperature were simultaneously reduced, decreasing on average by 70% at the coldest temperatures, whereas increasing on average by 25% at the elevated temperature condition. In vitro lung dose is strongly dependent on both inhaler temperature and ambient temperature with the tested pMDIs.