In this study, we developed and validated a LC-MS/MS method for the determination of Fluticasone propionate and Fluticasone 17β-carboxylic acid propionate (Fluticasone metabolite) in human K3EDTA plasma using Fluticasone propionate-d5 and Fluticasone 17β-carboxylic acid propionate-d3 as the internal standards (IS) using positive and negative TIS switch during analysis