Monitoring safety of liposomes containing rifampicin on respiratory cell lines and in vitro efficacy against Mycobacterium bovis in alveolar macrophages

Abstract

Rifampicin-encapsulated liposome suspensions were prepared by a chloroform-film method and converted to dry powders by freeze-drying with mannitol as a cryoprotectant. The liposome suspension had multilamellar nanovesicles with 50% rifampicin encapsulation. The liposome dry powder comprised particles with a mass median aerodynamic diameter of 3.4 μm, with 60% present as a fine particle fraction. Rifampicin-encapsulated liposomes were evidently nontoxic to respiratory associated cells, including bronchial epithelial cells, small airway epithelial and alveolar macrophages (AMs). Furthermore, the liposomes did not activate AMs to produce interleukin-1β, tumor necrosis factor-α, and nitric oxide at a level that would cascade to other inflammatory effects. The minimum inhibitory concentrations against Mycobacterium bovis was 0.2 and 0.8 μM for liposomes containing rifampicin and free rifampicin, respectively. The less negatively charged reconstituted liposome displayed the greatest activity against intracellular growth of M. bovis.

Keywords::

• Tuberculosis
• liposomes
• m-cell
• targeted drug delivery

Acknowledgements

This work was supported in part by the National Research Council of Thailand and NANOTEC center of excellence at Prince of Songkla University, Thailand. We also acknowledge Prof. L.A. Damani for editing this manuscript. In addition, we also thank Dr. Usanee Vinitketkumneun and Dr. Kanittha Punturee from the Department of Biochemistry, Faculty of Medicine, Chiangmai University for their kind technical supports and assistance.

Declaration of interest: The authors report no conflicts of interest.