Validation of BUD module of the ICSpkTS R extension package. Empty circles, observed plasma concentration after inhalation of a single dose of 1,000 mcg BUD (n = 14) (30). Grey-shaded area, 90% prediction interval based upon simulated plasma concentrations after inhalation of a single dose of 1,000 mcg BUD (n = 1,000) using the BUD module of the ICSpkTS R extension package