The antimicrobial peptide M33 is a molecule currently in preclinical development phase for the set up of a new antibiotic drug for lung infections in cystic fibrosis patients. This project will study the most suitable delivery systems to enhance its effectiveness. Inhalable formulation based on M33-loaded microparticles or nanoparticles will be used to allow optimal delivery to the pulmonary infection sites. After encapsulation, the developed M33 formulations will be tested in vitro and in vivo (mice infected in the lungs with P. aeruginosa) for their efficacy and possible toxicity. Proponents expect to get results applicable in humans within a few years.