| 초록 |
Purpose: For clinical application of beta-emitter labeled antibody, high specific activity is important. Carrier-free 188Re from 188W/188Re generator is an ideal radionuclide for this purpose. However, low stability of 188Re labeled antibody, especially in high specific activity, due to radiolytic decomposition by high energy (2.1 MeV) beta ray was problem. We studied the stability of 188Re labeled antibody, and stabilizing effect of several stabilizers. Materials and Methods: Pre-reduced monoclonal antibody (CEA79.4) was labeled with 188Re by incubating with generator-eluted 188Re-perrhenate in the presence of stannous tartrate for 2 hr at room temperature. Radiochemical purity of each preparation was determined by chromatography. Human serum albumin was added to the labeled antibodies (2%). Stability of 188Re-CEA79.4 was investigated in the presence of ascorbic acid, ethanol, or Tween 80 as stabilizing agents. Results: Labeling efficiencies were 88 4% (n=12). Specific activities of 1.25∼4.77 MBq/㎍ were obtained. If stored after purging with N2, all the preparations were stable for 10 hr. However, stability decreased in the presence of air. Perrhenate and 188Re-tartrate was major impurity in declined preparation. Colloid-formation was not a significant problem in all cases. Addition of ascorbic acid stabilized the labeled antibodies either under N2 or under air by reducing the formation of perrhenate. Conclusion: High specific activity 188Re labeled antibody is unstable, especially, in the presence of oxygen. Addition of ascorbic acid increased the stability. (Korean J Nucl Med 2002;36;195-202) |
