ROTAHALER Device Optimization Study

This study will compare the pharmacokinetic (PK) of Fluticasone Propionate/Salmeterol combination (FSC) 100/50 micrograms (mcg) delivered via the capsule-based inhaler (Rdpi) relative to FSC 100/50 mcg delivered via the multi-dose dry powder inhaler (Ddpi) to establish whether the Rdpi inhaler has exposure (in terms of fluticasone propionate area under time concentration curve \[AUC\] and Salmeterol maximum concentration \[Cmax\]) no greater than 1.2500 compared to the Ddpi, sufficient to allow progression to Phase 3. This study will enroll 36 healthy adult male and female subjects and each subject will be allocated to one of two sequences and will participate in four treatment periods, receiving each of the treatments twice.