physicochemical evaluation of lyophilized formulation of p-scn-bn-dota-and p-scn-bn-dtpa-rituximab for nhl radioimmunotherapy

radioimmunotherapy (rit) of non-hodgkin’s lymphoma (nhl) is said to be more advantageous compared to unlabelled therapeutic antibodies. to this date, radiolabelled murine anti-cd20 mabs, zevalin® and bexxar® have been approved for imaging and therapy. a preparation containing rituximab, chimeric mab radioimmunoconjugate suitable for lu-177 labeling, could provide better imaging and therapeutic profile at the same time. this study was conducted to evaluate prepared lyophilized formulations of two rituximab immunoconjugates, intended for immediate lu-177 labeling, for imaging and therapy.the characterization of the conjugates and demonstration of the integrity of the protein and purity after conjugation and lyophilization was performed by sds-page, ft-ir and maldi-tof-ms. the results showed preserved antibody structure and average of 6.1 p-scn-bn-dota and 8.8 p-scn-bn-dtpa groups per antibody molecule which is suitable for successful labeling. these results support the possibility of developing a “ready-to-label” rituximab immunoconjugates for nhl imaging/therapy.