In vitro/In vivo Evaluation of Elastic Nano-lipid Carriers of Aztreonam for Pneumonic Lungs

Background: The liposomal inhalation of drugs has been extensively researched for the invasion of biofilms and macrophages in the infected lungs. Objective: The present study aimed to explore the in vitro and in vivo effects of elastic nano-lipid vesicles of aztreonam for pulmonary delivery. Methods: Elastic nano lipid vesicles of the drug were successfully prepared with the commonly abundant lung phospholipids (LIPOID S PC-3, LIPOID PC 16:0/16:0), cholesterol, and span 20. Four such formulations were evaluated for their physicochemical properties, in vitro diffusion, and cytotoxicity. The best formulation was subjected to stability, in vivo drug deposition on the pneumonic lungs, and histopathological studies. Results: The characterization of the lipid vesicles in terms of particle size, zeta potential, and surface morphology confirmed the formation of stable nanolipid vesicles of the drug. The presence of surfactant in the lipid vesicles exhibited high bilayer stability, entrapment, and diffusion of the drug. The in vitro diffusion study revealed the biphasic characteristic with an initial burst, followed by sustenance for 8 h. A remarkable drug uptake was observed in the epithelial cell line of CHO Cricetulus griseus in the presence of surfactant. The drug was retained on the pneumonic lungs for 8 h. The histopathological study of lung tissue revealed that surfactant-based lipid vesicles could attenuate lung fibrosis significantly. Conclusion: It can be concluded that elastic nano lipid vesicular system of aztreonam could be a paradigm for targeting and localization of the drug with a long residence time in the lungs.