Preparation and biological evaluation of [Ga-67]-labeled-superparamagnetic nanoparticles in normal rats

Gallium-67 labeled superparamagnetic iron oxide nanoparticles ([Ga-67]-SPION were prepared and evaluated for their altered biodistribution in normal rats. Superparamagnetic iron oxide nanoparticles (SPION) with narrow size distribution were synthesized by a co-precipitation technique using ferrous salts at Fe3+/Fe2+ = 2 molar ratio followed by structure identification using XRD, TGA, DSC, VSM, HRSEM, TEM and FT-IR techniques (approximate to 5 nm diameter). In order to trace SPION bio-distribution, the radiolabeled iron oxide nanoparticles were prepared using Ga-67 with a high labeling efficiency (over 96%, RTLC method) and they also showed an excellent stability at room temperature for at least 4 d. The biodistribution of the radiolabeled SPION was checked in normal male rats up to 24 h compared to free Ga3+ cation biodistribution. The data strongly support the alteration of the tracer accumulation in reticuluendothelial system while the stability of the complex is highly retained.