NUKLEONIKA 2009, 54(4):271-277



Ali Bahrami-Samani1, Mohammad Ghannadi-Maragheh1,2, Amir R. Jalilian3,
Hassan Yousefnia3, Javad Garousi3, Sedigheh Moradkhani3

1 Faculty of Nuclear Engineering and Physics,
Amirkabir University of Technology, P. O. Box 15875-4413, Tehran, Iran

2 Agricultural, Medical and Industrial Research School (AMIRS), P. O. Box 31485-498, Karaj, Iran
3 Radiopharmaceutical Research & Development Laboratory (RRDL),
Nuclear Science and Technology Research Institute (NSTRI),
14395-836 Tehran, Iran

Combining beta-particle effect with therapeutic properties of anti-CD20 monoclonal antibody in lymphomas, Mabthera™ (rituximab) was targeted in this study. The antibody was labeled with 153Sm-samarium chloride (185 MBq) after conjugation with freshly prepared ccDTPA. Conjugated-rituximab was obtained by the addition of 1 ml of a ritu-ximab pharmaceutical solution (5 mg/ml, in phosphate buffer, pH = 7.8) to a glass tube precoated with freshly prepared ccDTPA (0.01–0.1 mg) at 25°C. Sm-153 chloride was obtained by a thermal neutron flux (5 × 1013 n cm–2 s–1) of an enriched 152Sm2O3 sample, dissolved in acidic media. Radiolabeling was performed in one hour by the addition of DTPA-rituximab conjugate at room temperature. Radiochemical purity of 96% (ITLC) and 98% (HPLC) were obtained for the final radioimmunoconjugate (specific activity = 120 TBq/mmol). The final isotonic 153Sm-rituximab complex was checked by gel electrophoresis for protein integrity retention. Biodistribution studies in normal rats were performed to determine radioimmunoconjugate distribution up to 24 h. SPECT images were also obtained using 103 keV photons up to 48 h.

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