Acute lung injuries caused due to inhalation of toxic irritant gases such as ammonia, chlorine, hot smoke and burning plastic fumes predominantly affect the airways, causing tracheitis, bronchitis, and other inflammatory responses. The purpose was to develop and characterise nanoparticle based fluticasone propionate (FP) DPI formulation and assess its in vitro and in vivo pulmonary deposition using pharmacoscintigraphy. FP nanoparticles were prepared by nanoprecipitation method. Optimisation was carried out with the help of Box-Behnken statistical design. Nanoparticles were characterised with the help of SEM, FT-IR, DSC and XRD. Anderson cascade impaction showed that nano-FP exhibited significantly higher respirable fraction of 60.3 +/- 2.41 as compared to 16.4 +/- 0.66 for micronised form. Ventilation lung scintigraphy in human volunteers confirmed significant increase in drug delivery till alveolar region with nano-FP in comparison to micronised drug. Results indicate that the developed formulation may have a potential prophylactic/therapeutic role against toxic, irritant gas inhalation.