Compare the Effects of Seretide Evohaler and a Generic Salmeterol/Fluticasone Hydrofluoroalkane (HFA) Pressurized Metered-dose Inhaler (pMDI) on Functional Respiratory Imaging Parameters in Asthmatic Patients

The primary objective of this study is to evaluate the effect of both the study drugs under investigation on Functional Respiratory Imaging (FRI) parameters and to evaluate the particle deposition in the lungs using Computational Fluid Dynamic (CFD)