[Evaluations of a specified number of inhalations and how to assess the contents in metered-dose inhalers].

Many kinds of Metered-Dose Inhalers (MDI) have been clinically available for bronchial asthma. Although manufacturers demonstrate the specified number of inhalations per canister on an attached document or on a plastic bag, the information provided are usually inadequate and inconsistent. They provide no information on the problems of the Metered-Dose Inhalers beyond the maximum specified number of actuations and the time when to exchange for a new one. We examined the technique how to evaluate the contents of MDI and their accuracy. Patients and their parents depended on inaccurate methods, such as shaking the inhalers to listen to the sound of contents, estimating the weight of the canisters and the size of emissions, and only a half of them were able to distinguish between 1/3 and 2/ 3 of remaining doses. Three Metered-Dose Inhalers with anti-inflammatory drugs and one MDI with beta-stimulant supplied consistent doses until they reached the maximum specified number. The 4 MDIs floated in the water in different ways and provided information when to replace for new ones in some MDIs.