99mTc carbonyl DTPA-Rituximab: Preparation and preliminary bioevaluation

The anti CD20 antibody Rituximab was conjugated with para isothiocyanato benzyl diethylene triamine penta acetic acid (p-NCS-Bz-DTPA) and subsequent radiolabeling with 99mTc was carried out via the 99mTc carbonyl synthon. The 99mTc labeled antibody conjugate exhibited >95% radiochemical purity after purification and retained good in vitro stability when studied up to 24 h at room temperature. In vitro cell binding studies carried out in Raji cells expressing CD20 antigen validated the biological efficacy of the preparation.