Evaluation of Effective Parameters on Labeling of Hydroxyapatite Compound with 90Y and Introducing the Best Method to Produce 90Y-HAp Radiopharmaceutical for Radiosynovectomy

Radiosynovectomy is a local intra-articular injection of radionuclides in colloidal form for treatment of articular inflammatory in rheumatoid arthritis, hemophilia or orthopedic troubles. β-emitting radionuclides can be used for various joints based on radiation energy. 90Y is a pure β-emitter with a half-life of 64.1 hours that is used for treatment of the knee joint. β-radiation of this radionuclide possesses maximum energy of 2.281 MeV (99.98%), mean pathway of 3.6 mm in the soft tissue and maximum 11 mm. In this project, hydroxyapatite (HAp) is applied as a colloid maker agent that interacts with 90Y3+ ions via ion-dipole bonds and produces 90Y-HAp. The colloidal pharmaceutical is produced by adding an acidic solution of 90YCl3 to an HAp suspension in saline. Effective parameters within which the colloid is applied, such as the volume of diluent, HAp particle size and sonication effect were evaluated and tested. First, these determinative parameters were optimized in the simulated conditions and then examined in the active phase. Finally, the best procedure was determined for the production of the radiopharmaceutical. Radionuclide purity of the radiopharmaceutical according to the primary 90YCl3 solution was over 99.9%. Labeling yield and radiochemical purity were obtained over 99% using TLC method in saline solvent up to three days after production of radiopharmaceutical. Radiochemical purity of 90Y-HAp colloid was also evaluated in human serum albumin solution for three days at room temperature. The amount of released activity was between 0.3 to 2%.