Researchers identified a short-sized antimicrobial peptide (AMP) from frog skin (21 amino acids), Esc(1-21), that shows to kill Pseudomonas aeruginosa (P.a.) and to prevent biofilm developing (FFC Projects #14/2011, #11/2014). Further, they designed a diastereomer of Esc (1-21), more stable and less cytotoxic than the wild-type peptide; more efficient in stimulating migration of bronchial cells and presumably in promoting recovery of the bronchial epithelium integrity. Now their aims are the development of Esc(1-21) and/or its diastereomer as new effective and economically feasible drugs and the production of polymeric nanoparticles (NPs) to assist the peptide diffusion through the bronchial mucus, upon airway administration. Antibacterial activity of the new compounds will be studied when used alone or in combination with conventional antibiotics/mucolytic agents. In parallel, preclinical testing in mouse models of acute P.a. lung infection will be carried out, as well as the in vivo antipseudomonal activity of the peptide-loaded NPs. These latter could be further developed into dry powders for inhalation allowing a much easier and faster administration route.