Introduction of new derivatives of Biotin and DTPA for labeling of antibodies with ¹¹¹In to detect malignant tumors [Persian]

Document Type: Original Article


1 Faculty of Pharmacy, Shaeed Beheshti University of Medical Sciences, Tehran, Iran

2 Faculty of Medicine, Bandarabas University of Medical Sciences, Bandarabas , Iran

3 Department of Radioisotope, Nuclear Research Center, AOEI, Tehran, Iran


Radiolabeled monoclonal antibodies, have created new innovations in diagnosis, research and therapy of disease in last 2 decades. One of the serious limitation of applications of radiolabeled antibodies in vivo is relatively low target to background activity. Various strategies have been proposed to solve this problem including pre-targeting methods that was suggested in 1989. Regarding importance of monoclonal antibodies and radioisotopes, based on pre-targeting strategy, we have introduced new derivative of Biotin and DTPA to decrease background activity. DTPA-bio and new derivative (DTPA-bio-1OX) were labeled with ¹¹¹In, labeled compounds and injected through tail veins into Balb/c mice, and percent of injected dose per gram of blood (%ID/g of blood) was determined at 15, 30, 60, 120, 180, and 240 min after injection. Based on results,¹¹¹In-DTPA-bio rapidly cleared from serum, indicating molecular weight of label is increased causing delayed clearance from serum. Therefore, there is enough time for label to accumulate in the target tissues. With advent of second generation of monoclonal antibodies and antibody engineering, pretargeting methods have changed greatly. It seems that derivatives we introduced will have an important role in new pre-targeting methods.


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