This article discusses in vitro testing that can support the development of new and generic metered dose inhalers
Caused by impaction of the delivered dose and the rapid evaporation of any remaining propellant (and in some cases, volatile co-excipients as well), the cold freon effect strongly influences the efficiency of drug delivery. It may, for example, cause the patient to abort or be unsuccessful in completing the inhalation manoeuvre. Quantifying this phenomenon is therefore important when aiming to replicate or improve inhalation behavior and MDI performance.