«Synoren, 188 Re» – A promising radiopharmaceutical for radiosynovectomy

Abstract

The article presents results of investigation into efficiency of the new radiopharmaceutical (RPh) "Synoren, 188 Re" for synovitis treatment. The research was performed on laboratory animals with modeled joint pathology. The radiopharmaceutical can be produced as finished form or it can be prepared with the use of lyophilized reagents with the radionuclide generator 188 W/ 188 Re in laboratories for radionuclide studies and radionuclide therapy departments. Radiochemical purity of "Synoren, 188 Re" ≥90%. The RPh is a suspension with particle size of 2-10 μm, colloidal particles labeled with rhenium-188 are distributed homogeneously in the joint. The radiopharmaceutical was administered intra-articularly in the knee with modeled acute asymptomatic synovitis. "Synoren, 188 Re" has retained in the inflammation site for about three days after the administration. Therapeutic properties of "Synoren, 188 Re" were preserved for about 72 hours after the administration. Therapeutic efficiency was assessed by changes in locomotor activity as compared with the activity before the administration of the RPh. The follow up has lasted for a week after the administration of the "Synoren, 188 Re". Support ability of the damaged extremity in rats was assessed using the device, designed to study pain sensitivity in the absence of external pain stimulus, the ability in rabbits was measured by the distance running and pain severity on palpation of the damaged joint. The positive response to treatment was observed in all animals. After administration of the RPh improved support ability was registered in rabbits, reduction of pain intensity in the damaged joint was registered in rats. In animals of control groups (the RPh was not administered) no positive changes were observed. Therapeutic dose of the radiopharmaceutical did not produce toxic effect on normal tissues. Results of research strongly suggest that "Synoren, 188 Re" is an effective treatment for inflammatory joint diseases.