Study of N‐vinylpyrrolidone‐N‐vinylformamide copolymers labelled with indium‐113m

The procedure of the directed synthesis of N‐vinylpyrrolidone‐N‐vinylformamide (VP‐VFA) copolymers with grafted iminodiacetate (IDA) chelating units is presented. The methods for labelling resulting conjugates with indium‐113m were developed. The metal‐copolymer conjugates were characterized by different physicochemical methods, including IR and NMR, viscometry, light scattering, and exclusion high‐performance liquid chromatography. Parameters of radiochemical synthesis of the conjugates labelled with indium‐113m were optimized. It was shown that the VP‐VFA‐IDA copolymer firmly binds indium‐113m both in the acid and alkaline solutions, with pH of the reaction mixture having almost no effect on the complexation. VP‐VFA‐IDA‐In conjugates were found to be unstable in histidine challenge reaction. The procedure of the directed synthesis of VP‐VFA copolymers with grafted IDA chelating units was developed. Labelling the copolymer with indium‐113m was studied. Resulting conjugates were found to be unstable in interligand exchange reaction with histidine.