In vitro and in vivo study of solid lipid nanoparticles loaded with superparamagnetic iron oxide.

Solid Lipid Nanoparticles (SLN) are already under investigation as a pharmaceutical tool able to change the pharmacokinetic and biodistribution of carried molecules. SLN are able to target drugs to lymph after duodenal administration and to overcome the Blood Brain Barrier (BBB). In this study, superparamagnetic SLN have been prepared, have colloidal size, in vitro analysis showed relaxometric properties similar to Endorem. In vivo Magnetic Resonance Imaging (MRI) of the central nervous system (CNS) with both SLN and Endorem showed that superparamagnetic SLN have slower blood clearance than Endorem. MRI data are consistent with CNS uptake of SLN lasting up to the end of the experiment (135 min). These findings confirm the ability of SLN to overcome the BBB; SLN might be used as a CNS MRI contrast agent.