The delivered dose from a nebulizer is tested by using a lung simulator that generates a tidal inhale/exhale breathing pattern through the device. To slow down the evaporation of the nebulized droplets in the impactor, the cascade (APSD) testing is performed using cooled impactors.
The pharmacopeial assessment of nebulizers is described in European Pharmacopeia 2.9.44 and in US Pharmacopeia <1601>.