Rapid miniaturized chromatography for 111In labeled monoclonal antibodies: comparison to size exclusion high...

Our laboratory investigated the use of a rapid miniaturized chromatography system, ITLC-SG with 0.9% NaCl, to assess the radiochemical purity of 111In labeled monoclonal antibodies (MoAbs). Radiochemical analysis was performed on numerous 111In labeled antibody preparations with labeling efficiencies ranging from 40 to greater than 95% and the results compared to those obtained with size exclusion high performance liquid chromatography (HPLC). The chromatographic procedure involved challenging radiolabeled antibodies with 0.05 M DTPA to chelate unbound and/or non-specific bound 111In, spotting on miniaturized instant thin layer-silica gel chromatography strips, developing in 0.9% NaCl, and counting appropriate segments for radioactivity. Results of the study demonstrated that the miniaturized chromatography procedure was rapid, taking less than 4 min to complete, and accurate in assessing the amount of unbound or non-specific bound 111In in 111In labeled monoclonal antibodies, when compared to size exclusion HPLC.