Preparation and Biodistribution of ~(99)Tc~m-MAG_3-Lys-mPEG

Starting with mPEG-5000,Fmoc-Lysine,and mercaptoacetyltriglycine(MAG_3),the carrier MAG_3-Lys-mPEG is synthesized through five steps,which carrier is labeled by ~(99)Tc~m with labeling efficiency >98%.~(99)Tc~m-MAG_3-Lys-mPEG shows high stability in vitro.The radiochemical purity keeps up >91% and >92% after incubation in saline for 24 h and in bovine serum for 16.5 h,respectively.The biodistribution in mice indicates that ~(99)Tc~m-MAG_3-Lys-mPEG is quickly cleared from blood,and excreted mainly through the urinary systemr.There is the highest uptake in kidneys.It is expected that mPEG may be used as an effective ASODN carrier.