ABSTRACT
Generally, when SLN reach the blood stream, these may avoid the macrophage uptake due to their small size and surface characteristics. In addition, thanks to their lipophilic features, these systems could reach the CNS overcoming the BBB by an endocytosis or a transcytosis mechanism which occurs in the endothelial cells lining the brain blood capillaries, or SLN could also permeate the tight junctions between the endothelial cells (Denora et al. 2009; Joshi and Müller 2009). The absorption of a plasmatic protein, the Apoliprotein E, onto nanoparticle surface is supposed to be responsible for the brain SLN uptake by mediating its adherence to the endothelial cells of the BBB (Blasi et al. 2007; Joshi and Müller 2009). The transport mechanisms of free drugs or drug-loaded SLN across the BBB are reported in Fig. 3.
