PRELIMINARY STUDY FOR PREPARATION AND CHARACTERIZATION OF RADIOIMMUNOCONJUGATE LU-177-DOTA-RITUXIMAB Veronika Yulianti Susilo1, a) Martalena Ramli1,b) Sri Setiyowati1,c) Abidin1,d) Rien Ritawidya1,e) Titis Sekar Humani1,f)
Research Center for Radioisotope, Radiopharmaceutical and Biodosimetry,
National Research and Innovation Agency
Abstract
Requirements of radioimmunotherapy is radionuclides binding to monoclonal antibodies (mAb) were stable and specific recognize tumor associated antigens. Most of the B cell lymphoma express CD20 antigen on the surface of tumor cells, that the target protein CD20 mAb suitable for therapeutic radioactive labeled. In this study, the immunoconjugate of Rituximab and macrocyclic chelator, pSCNBzDOTA, was prepared and radiolabelled using Lutetium177, and then characterized for radiochemical purity of the complex. Rituximab desalted with 0.1 M phosphate buffer pH 8.5 and conjugated with pSCNBz-DOTA in the ratio 1: 20. Result of conjugation was analyzed by high performance liquid chromatography and concentration of protein was measured by protein reader, then dispensing each 2 mg/mL and was dried with a freeze drier. The immunoconjugate was labeled using Lutetium177, the labeling was be carried out with mole ratio variation of DOTA rituximab against Lutetium177 and reaction time. Radiochemical purity of labeling results was characterized using chromatography method with ITLCSG as stationary phase and a mobile phase of 0.9% saline solution. Radiochemical purity of the radioimmunoconjugate complex before purification is 54% in mole ratio of 1:1 and a reaction time of 30 minutes. Radioimmunoconjugate was purified by sephadex G25 column with a yield of purification is 40.03% and radiochemical purity of each fraction on average by 99.98%.
Keywords: CD20, rituximab, Lutetium-177, radioimmunotherapy, mAb
