Comparative in vitro performance of valved holding chambers with a budesonide/formoterol pressurized metered-dose inhaler

A combination of budesonide and formoterol in a single pressurized metered-dose inhaler (pMDI) is available in the United States and elsewhere. This study was designed to evaluate the delivered dose and fine particle dose (FPD; mass of particles <4.7-micrometer diameter) using the pMDI with two valved holding chambers (VHCs), using sampling methods reflecting different patient techniques. FPD was measured using an Andersen Cascade Impactor and delivered dose was measured using a disposable filter. Two VHCs, AeroChamber Plus and AeroChamber MAX (Trudell Medical International, London, Ontario, Canada), were evaluated using three sampling methods: (1) immediate collection; (2) collection after tip to a 5-second delay, (3) using simulated adult, child, and infant tidal breathing patterns (delivered dose). Decreases in delivered dose were observed using a VHC compared with the pMDI alone. FPD with both VHCs was similar to that with the pMDI alone with minimal delay between actuation and collection. With delays, the antistatic AeroChamber MAX was more resistant than AeroChamber Plus to dose losses. Delivered doses from adult and child profiles were comparable with those after a I-second delay. The infant profile produced lower delivered doses, probably because more breath cycles are required to empty the VHC. Budesonide/formoterol pMDI can be used effectively with AeroChamber Plus and the antistatic AeroChamber MAX. With minimal delay between actuation and collection, FPD with both VHCs was similar to that with the pMDI alone, giving physicians a choice of administration regimen and taking into account the needs and skills of the patient. (Allergy Asthma Proc 30:424-432, 2009; doi: 10.2500/aap.2009.30.3252)