Effect of chitosan coating in overcoming the phagocytosis of insulin loaded solid lipid nanoparticles by mononuclear phagocyte system

In this work, RAW 264.7 cell line was used to investigate the macrophage internalization of insulin-loaded SLN coated with chitosan. SLN were prepared by the w/o/w double emulsion method with different lipids and two different surfactants, Pluronic and Tween 80, following chitosan coating. Witepsol 85E based SLN were suitable for dimensions, sizing between 200 and 400 nm and insulin association efficiency was around 60% for both surfactants. Fluorescence microscopy confirmed that chitosan coated SLN were neglectfully internalized within RAW 264.7 cells as compared with uncoated SLN and with polystyrene latex nanoparticles as positive control, which were fully taken up. These results were quantitatively confirmed by flow cytometry assay. Chitosan-coated SLN demonstrated to be potentially able to prolong insulin blood levels and to avoid phagocytosis by MPS after intestinal uptake.