Rifampicin loaded mannosylated cationic nanostructured lipid carriers for alveolar macrophage-specific delivery.

In this study, cationic mannosylated nanostructured lipid carriers (Man-NLCs) were developed for the targeted delivery of rifampicin to alveolar macrophages. Rifampicin loaded Man-NLCs (RFP-Man-NLCs) and rifampicin loaded unmodified nanostructured lipid carriers (REP-NLCs) were prepared using thin film homogenization method and characterized by particle size, polydispersity index, zeta potential, transmission electron microscopy, encapsulation efficiency, pharmacokinetics, biodistribution, cell specific targeting, cytotoxicity and inflammatory response. RFP-Man-NLCs and REP-NLCs obtained displayed a size distribution around 160 nm (PDI <0.30) with positive charges of approximately 30 mV. The encapsulation efficiency of RFP was above 90%. In the biodistribution study, both RFP-Man-NLCs and RFP-NLCs, compared with the commercially available rifampicin solution, displayed superior lung-targeting ability. Compared to REP-NLCs, RFP-Man-NLCs exhibited significantly higher uptake efficiency in NR8383 cells and alveolar macrophages, which achieved cell-specific targeting. In addition, RFP-Man-NLCs were demonstrated to be a safe formulation with minimum toxicity and no inflammatory response. RFP-Man-NLCs provided an alternative strategy for selectively delivering rifampicin to alveolar macrophages.