Abstract
AIMS: To determine in vitro the effect of delay, inspiratory flow, and spacer washing on the drug output of metered dose inhalers (MDIs) used with different spacer devices. METHODS: The amount of drug in particles <5 microm diameter from MDI+spacer, sampling after a delay of up to 20 s, was measured using a Multistage Liquid Impinger. Drug output was also measured at different flow rates, and after washing the Babyhaler in household detergent. RESULTS: More fluticasone in small particles was recovered from the Babyhaler than the Volumatic or the Aerochamber spacers, and more beclomethasone and salmeterol was recovered from the Babyhaler and Volumatic spacers than from the Aerochamber. Washing the Babyhaler reduced the recovery of salmeterol, and did not alter the recovery of the other drugs tested. CONCLUSIONS: Spacer devices need to be fully evaluated for each drug prescribed for them.