Bioevaluation of (90)Y-labeled particles in animal model of arthritis

The aim of the present study was to evaluate the behaviour of (90)Y-labeled particles when injected into an arthritic knee joint of Wistar rats with severe inflammation induced using Complete Freund's Adjuvant (CFA).

(90)Y-ferric hydroxide macroaggregates ((90)Y-FHMA), (90)Y-hydroxyapatite ((90)Y-HA) and (90)Y-phosphate particles ((90)YPO(4)) were prepared, subjected to quality control analyses and in vitro stability studies. Biodistribution studies were carried out by intra-articular injection into knee joints of Wistar rats induced with chronic inflammatory arthritis using CFA and by monitoring the radioactivity for retention and leakage.

All the three preparations exhibited ~99% localization in knee joints even at 24 h p.i. with very small amounts observed in the liver and lungs, possibly due to leakage of the radiolabeled particles from the inflamed knee joint. Absence of any radioactivity in the femur indicated the in vivo stability of the particle preparations.

The biodistribution patterns were very similar in the normal and arthritic rats and were associated with negligible leakage (up to 24 h) from the knee joint indicating the potential of all the (90)Y-radiolabeled preparations reported here, for use in radiation synoviorthesis.