Formulation, Characterization and Bio-evaluation of Holmium-166 labeled Agglomerated Iron Oxide Nanoparticles for Treatment of Arthritis of Knee Joints

Abstract

Owing to its ideally suited nuclear decay properties [T½ = 26.9 h, Eβ(max) = 1.85 MeV, Eγ = 81 keV (6.4%)] and availability in adequate quantity at an affordable cost, 166Ho is an attractive choice for treatment of arthritis of knee joints. Production of 166Ho in nuclear reactor and development of a radiochemical formulation for radiation synovectomy using highly agglomerated iron oxide nanoparticles having 1-10 μm size range are reported. Surface of agglomerated iron oxide nanoparticles were radiolabeled with 166Ho in high yield when dispersed in 0.1 M NaHCO3 solution at pH ∼8. EDX analysis showed loading of 7 atom% of Ho with respect to Fe. The radiolabeled particles exhibited excellent in vitro stability when stored in normal saline and serum at 37°C. Biodistribution studies performed after intra-arterial injection of the 166Ho-labeled particles into one of the knee joints of a normal Wistar rats showed near-complete retention of the injected activity (> 98%) within the joint cavity even after 72 h post injection. This observation was also confirmed from the sequential whole-body radio-luminescence imaging studies in the animal model. The reported agent could emerge as a potential radiochemical formulation potential material for treatment of arthritis of knee joints.