DIRECT LABELING OF MONOCLONAL-ANTIBODIES AND ANTIBODY FRAGMENTS WITH RE-188 USING A WEAK COMPETING LIGAND

Different kit formulations for the direct labeling of MoAb-IOR CEA1 an d its F(ab')(2) fragments with Rhenium-188, using EHDP as a weak compe ting ligand, were developed. The influence of reaction conditions such as pH, temperature, weak ligand con centration and stannous chloride concentration during the preparation of Re-188-MoAb radioimmunoconjuga tes, were investigated in detail in order to obtain high radiochemical yields. Results showed that under different reaction conditions, radi ochemical purities over 95% were obtained in 1 to 2 h periods after ad dition of perrhenate solution eluted from the W-188/Re-188 generator t o a kit formulation. The procedure reported herein demonstrated the ov erall usefulness for the preparation of pure Re-188-antibody fragments .