The VENTOLIN Mini-Spacer is being developed in order to support patients in the Emerging Markets and Asia Pacific regions who do not have access to affordable spacers. The aim of this exploratory study is to investigate whether the systemic exposure for fluticasone propionate (FP) and salmeterol observed with the VENTOLIN Mini-Spacer is comparable to the systemic exposure for FP and salmeterol observed with the Trudell Aerochamber Plus spacer for both FLIXOTIDE and SERETIDE Metered Dose Inhaler (MDI) products. There will be four study periods in the study and all participants will receive four study treatments during the study. The total duration of study including screening, treatment period, washout period, and follow-up period will be 58 days. Study is planned to enroll 20 healthy subjects.