Development of Inhalable Chitosan-Coated Oxymatrine Liposomes to Alleviate RSV-Infected Mice.

Human respiratory syncytial virus (RSV) infection is the most important cause of acute lower respiratory tract infection in infants, neonates, and young children, even leading to hyperinflation and atelectasis. Oxymatrine (OMT), originating from natural herbs, possessed potential antivirus activity against influenza A virus, Coxsackie B3 virus, and RSV, whereas the absence of an in vivo study indicated the difficulties in overcoming the physiological obstacles. Since RSV basically replicated in lung tissue, in this study, we fabricated and characterized a chitosan (CS)-coated liposome with OMT loaded for the treatment of lethal RSV infection via inhalation. The results uncovered that OMT, as a hydrophilic drug, was liable to diffuse in the mucus layer and penetrate through the gas-blood barrier to enter systemic circulation quickly, which might restrict its inhibitory effect on RSV replication. The CS-coated liposome enhanced the distribution and retention of OMT in lung tissue without restriction from mucus, which contributed to the improved alleviative effect of OMT on lethal RSV-infected mice. Overall, this study provides a novel inhalation therapy for RSV infection, and the CS-coated liposome might be a potential inhalable nanocarrier for hydrophilic drugs to prevent pulmonary infections.