In vitro comparison of beclomethasone and salbutamol metered-dose inhaler aerosols inhaled during pediatric tidal breathing from four valved holding chambers.

STUDY OBJECTIVES

To determine the amount of salbutamol or beclomethasone delivered from metered-dose inhalers (MDIs) in particle sizes appropriate for inhalational treatment with four common holding chambers (AeroChamber, OptiChamber, Space Chamber, E-Z Spacer) when used under simulated pediatric tidal breathing conditions.

DESIGN

Five devices of each type were tested with salbutamol (100 microg, Glaxo-Wellcome) and beclomethasone (50 microg, Glaxo-Wellcome) MDIs. Each device was connected to face replicas representative of 7-month-old (infant), 2-year-old (toddler), and 4-year-old (child) children and aerosol inhaled into a cascade impactor (Anderson) using a valve system and simulated tidal breathing patterns representative of children of these ages.

MEASUREMENTS AND RESULTS

Amounts of drug inhaled in fine particles varied significantly between devices and ages (p < 0.01), eg, for beclomethasone, from 4 microg (infant, Space Chamber) to 8 microg (toddler, OptiChamber), and for salbutamol, from 18 to 36 microg. The AeroChamber and OptiChamber behaved quite similarly, delivering more drug in the fine particles than the other two devices, and having insignificant variations in these amounts with age (p > 0.05).

CONCLUSIONS

Amounts of drug inhaled in fine particles during pediatric tidal breathing from valved holding chambers are dependent on the holding chamber model, the drug used, and the breathing pattern, although dependence on the breathing pattern is relatively small for some of the devices tested.