Preparation and in vivo evaluation of multifunctional ⁹⁰Y-labeled magnetic nanoparticles designed for cancer therapy.

Two different types of magnetic nanoparticles (MNPs) were synthesized in order to compare their efficiency as radioactive vectors, Fe₃O₄-Naked (80 ± 5 nm) and polyethylene glycol 600 diacid functionalized Fe₃O₄(Fe₃O₄-PEG600) MNPs (46 ± 0.6 nm). They were characterized based on the external morphology, size distribution, and colloidal and magnetic properties. The obtained specific power absorption value for Fe₃O₄-PEG600 MNPs was 200 W/g, indicated their potential in hyperthermia based cancer treatments. The labeling yield, in vitro stability and in vivo biodistribution profile of (90) Y-MNPs were compared. Both types of MNPs were (90)Y-labeled in reproducible high yield (>97%). The stability of the obtained radioactive nanoparticles was evaluated in saline and human serum media in order to optimize the formulations for in vivo use. The biodistribution in Wistar rats showed different pharmacokinetic behaviors of nanoparticles: a large fraction of both injected MNPs ended in the liver (14.58%ID/g for (90)Y-Fe₃O₄-Naked MNPs and 19.61%ID/g for (90)Y-Fe₃O₄-PEG600 MNPs) whereas minor fractions attained in other organs. The main difference between the two types of MNPs was the higher accumulation of (90)Y-Fe₃O₄-Naked MNPs in the lungs (12.14%ID/g vs. 2.00%ID/g for (90)Y-Fe₃O₄-PEG600 MNPs) due to their in vivo agglomeration. The studied radiolabeled magnetic complexes such as (90)Y-Fe₃O₄-PEG600 MNPs constitute a great promise for multiple diagnostic-therapeutic uses combining, for example, MRI-magnetic hyperthermia and regional radiotherapy.