Purpose: The bronchodilator effect of salbutamol formulated in hydrofluoroalkane-134a (HFA-134a), a chlorofluorocarbon (CFC)-free propellant for metered dose inhalation (MDI) devices, was compared with that of salbutamol formulated in CFC in anesthetized dogs.
Methods: Bronchospasms were induced by the intravenous injection of histamine, and bronchial resistance was measured by the method of Konzett and Rossler.
Results: While the placebo vehicles (HFA-134a and CFC propellants) had no significant effect on histamine-induced bronchospasms, the salbutamol/HFA-134a and salbutamol/CFC MDI formulations had equivalent dose-related inhibitory effects.
Conclusions: These data indicated that salbutamol formulated in HFA-134a and that in CFC propellant are bioequivalent.