This is a single centre, double-blind, placebo-controlled, four-way cross over, randomized, single and repeat dose study. A total of 16 healthy subjects aged 18-45 years will be randomised with the aim of achieving at least 10 evaluable subjects to each treatment period. The primary objective is to evaluate the systemic steroid PD effects (serum cortisol 24 hour weighted mean on Day 7) of FF and systemic ß-adrenergic PD effects (ECG maximum QTcF 0-4h and whole blood potassium 0-4h in Day 1 and Day 7) of VI; the secondary objectives are aimed to evaluate the PK, safety and tolerability of FF/VI inhalation powder after a single and repeat dose administration.