Effect of Interval Between Actuations of Albuterol Hydrofluoroalkane Pressurized Metered-Dose Inhalers on Their Aerosol Characteristics

Abstract

BACKGROUND: Albuterol hydrofluoroalkane (HFA) either alone or with a valved holding chamber is used to treat bronchoconstriction. Delays between actuation and inhalation are common. Currently, the recommended interval between actuations of an albuterol HFA is 60 s. Using a shorter interval when multiple actuations are ordered will improve productivity in the hospital setting. METHODS: We studied aerosol characteristics of albuterol HFA (Ventolin, ProAir, and Proventil) with a cascade impactor calibrated at 30 L/min. We studied pressurized metered-dose inhalers (pMDI) alone, coupled to a nonelectrostatic valved holding chamber, and coupled to the valved holding chamber but introducing a 10-s delay between actuation and measurement. We tested intervals between actuations of 60, 30, and 15 s (not for delay scenario). The variable of most interest was fine-particle mass. Albuterol was measured by spectrophotometer (276 nm). RESULTS: Variations in fine-particle mass from 60-s values were < 15% for Ventolin and ProAir for all conditions tested and for Proventil with a valved holding chamber. Variations in fine-particle mass from 60-s values were > 15% for Proventil (pMDI alone with a 30-s interval and pMDI/valved holding chamber with delay and a 30-s interval). Adding a valved holding chamber increased fine-particle mass for all brands (ProAir 7-12%, Ventolin 26 -35%, and Proventil 44 -47%). The introduction of a 10-s delay reduced fine-particle mass for all brands (ProAir 34 -39%, Ventolin 39 -42%, and Proventil 27-32%). Comparison of fine-particle mass among brands showed that Proventil was > ProAir > Ventolin. CONCLUSIONS: Decreasing the interval between actuations from 60 to 30 and 15 s does not seem to affect the aerosol characteristics of ProAir and Ventolin. Although some changes were noticed for Proventil, the pMDI outperformed Ventolin that had the lowest fineparticle mass. The use of a valved holding chamber increased fine-particle mass, but introducing a 10-s delay between actuation and inhalation significantly reduced fine-particle mass.

Obstructive Airway Disease: Rational, Evidence-Based Bronchodilator Therapy

“…The Berlinski and Pennington study 1 in the September issue of RESPIRATORY CARE is of considerable interest, not only because it is good science, but also because it invites important clinical conclusions. The authors found that the previously held notion (see package inserts for hydrofluoroalkane Ventolin, Proventil, and Proair) that it is necessary to wait 60 s between albuterol puffs was clinically irrelevant, although probably statistically significant.…”