99m Tc-MDP as an imaging tool to evaluate the in vivo biodistribution of solid lipid nanoparticles.

The aim of this study was to establish the in vivo uptake and tissue distribution of 99m Tc-MDP-encapsulated Solid Lipid Nanoparticles (SLNs) post administration. Radioactive 99m Tc-MDP encapsulated into SLNs was administered to rats to trace their biodistribution through imaging and ex vivo studies. As expected IV injected 99m Tc-MDP exhibited predominant visual bone uptake and a high localisation of particles in the kidneys (3.87%ID/g) followed by bone (2.66%ID/g). IV administered 99m Tc-MDP encapsulated by SLN showed similar uptake than 99m Tc-MDP. Orally administrated 99m Tc-MDP showed no uptake in any organs except the GI-tract while orally administered 99m Tc-MDP-SLN showed distinct transfer of 99m Tc-MDP from the GI tract with measurable levels in the kidneys and bone.