Inhalable dry powders for chemically-modified human Cationic AntiMicrobial Peptides (CAMPs): moving toward in vivo application

The diffusion of pan drug resistant bacteria has highlighted the need of new antibiotics, but, so far, progress in developing them has been slow. At this regard, Cationic Antimicrobial Peptides (CAMPs) are a valuable alternative to conventional antibiotics because they have broad spectrum antimicrobial activity and low ability to induce the onset of resistant strains. These peptides are secreted from all multicellular eukaryotic organisms and represent an essential component of innate immunity, the first line of defence against microbial invasions. Even if the protein nature of CAMPs makes difficult their use as systemic agents they are ideally suited for direct delivery to airways and lung. The main aim of this project is to develop inhalable dry powders for lung???delivery of human CAMPs and CAMP releasing proteins (CAMP RPs) carrying simple chemical modifications which improve their antimicrobial activity. A wide panel of human CAMPs and CAMP???RPs will be prepared by recombinant DNA procedures and chemical synthesis, modified by means of a method already developed by the proponents and assayed on clinical P. aeruginosa strains to evaluate their bactericidal activity. The powders, containing one or more CAMP/CAMP RPs, will be prepared at different levels of complexity, exploiting not only technologies and excipients already used for the inhalation in humans, but also polymeric materials of choice in peptide/protein drug formulations already on the market. Moreover during the design and development of the particles we will be considered crucial parameters for transferability in vivo, such as aerodynamic properties, resistance to proteases, release profile of the drug in simulated lung fluids, ability to overcome extracellular pulmonary barriers (mucus, biofilm, etc..). The analysis of the interactions between CAMPs and acidic polysaccharides, such as alginate and hyaluronic acid, will allow to design rationally the inhalable particles. The most promising formulations will be tested in vivo in a murine model of acute P. aeruginosa, infection both alone and in association with ciprofloxacin, a common broad???spectrum antibiotic. A systematic approach devoted to strengthening natural human CAMPs and to the development of suitable formulations to administer them and able to fight infection by P. aeruginosa, particularly critical for patients with cystic fibrosis, perfectly meets the mission of the FFC.