The invention concerns a new galenic formulation of CFT (clofoctol) allowing the administration of this antibiotic in aerosol form with the objective of treating pulmonary infections (COVID-19, influenza...), cancer and inflammation thus targeting the diseased tissue while avoiding the problems of solubility of CFT and toxicity associated with this drug. This new formulation allows to answer these problems and concerns the development of polymeric nanoparticles (Nanoparticles) in suspension in an aqueous phase intended to be administrated in a form of aerosol or spray, said Nanoparticles comprising PLGA and PLGA-PEG polymers, allowing to obtain an effective encapsulation of CFT and a controlled release of CFT at the pulmonary level.