Abstract
Objective:
To determine whether storage at low temperatures affects the drug delivery efficacy of a chlorofluorocarbon (CFC)-free aerosol and a dry-powder inhaler (DPI).
Design:
Aerosol output from a CFC-free hydrofluoroalkane (HFA-134a) metered-dose inhaler (albuterol) and a multidose DPI (terbutaline) were examined at different ambient temperatures and canister loads.
Results:
After the HFA-134a formulation was stored at low temperatures for 24 hours, a small decrease of aerosol output (2.1–2.7% at 0 °C, 5.0–8.0% at −10 °C; p < 0.05 from 22 °C) was observed. In addition, the aerosol output from devices with one-half or one-fifth the initial content was marginally decreased compared with output from inhalers with full content. Image analysis techniques applied to fully formed aerosol plume emitted from the HFA-134a formulation showed that the product could still be aerosolized at 10 °C, but there was a reduction of the distance reached by the aerosol. In contrast, condensed droplets markedly altered the aerosols formed from CFC inhalers at −10 °C. Aerosol output from the DPI apparently was not altered following 24-hour storage at −10 °C.
Conclusions:
Aerosols emitted by the HFA-134a and DPIs studied were less affected by exposure to cold temperatures compared with those from marketed CFC devices.
Get full access to this article
View all access options for this article.