Study designs:

²This single-centre, randomized, double-blind, double-dummy four-way cross-over study in 24 moderately severe asthmatic patients compared the speed of onset of recommended doses of salbutamol (200 μg) and formoterol (12 μg) delivered by metered-dose inhaler in reversing the bronchoconstriction induced by methacholine. Specific airway conductance (SG_AW) and airway resistance (R_AW) were measured in baseline condition, immediately after challenge and 0.5, 15, 3, 5, 10, 15, 30, 60 min and every hour up to 4 h after inhalation of the trial drug. FEV₁ was measured in baseline condition, after challenge and 15, 30 and 60 min and then every 30 min up to 4 h after inhalation of the study drug. The primary efficacy parameter was the change in SG_AW.

⁴The study was a randomized double-blind, double-dummy; placebo controlled three-way crossover design. It was carried out at two centers: one in Sydney screened 58 subjects and one in Perth screened 12 subjects. A protocol for exercise-induced asthma (EIA) was used to compare the protective effect of salbutamol delivered by the pressurised metered dose inhaler (pMDI) and the new Diskus dry powder device. 27 asthmatic subjects with moderately severe EIA completed an exercise test on four separate days at two study centers. Cycling exercise of 8 min duration was used to increase ventilation, and subjects inspired compressed dry air. The ventilation, heart rate, and workload achieved in relation to predicted targets were measured.