Laboratory evaluation of metered-dose inhalers with models that simulate interaction with the patient.

: Laboratory evaluation of aerosol generating-devices is usually performed under conditions of constant airflow. The performance of aerosol-generating devices with different tidal volumes and inspiratory airflows encountered in clinical practice cannot be determined by these methods. To overcome this problem, models have been developed that simulate patients' breathing pattern, provide measurements of inhaled or respirable mass, and the proportion of aerosol exhaled. This article explores the development of such a model.