Introduction of Re(CO)/Tc(CO) Organometallic Species into Vinylpyrrolidone-Allyliminodiacetate Copolymers.

N-vinylpyrrolidone-co-allylamine copolymers (VP-co-AA) containing iminodiacetic (IDA) chelation units were prepared in the range of molecular masses of the copolymers from 9000 to 30,000 Da depending on polymerization conditions. Non-radioactive organometallic species Re(CO) were introduced into polymeric carriers under mild conditions; the prepared metal-polymeric complexes were characterized by IR, NMR, ESI-MS and HPLC. IR spectra data confirmed the coordination of M(CO) moiety to the polymeric backbone via IDA chelation unit (appearance of characteristic fac-M(CO) vibrations (2005, 1890 cm), as well as the appearance of group of signals in H NMR spectra, corresponding to those inequivalent to methylene protons CHCOO (dd, 4.2 ppm), coordinated to metal ions. The optimal conditions for labeling the PVP-co-AA-IDA copolymers with radioactive Tc(CO) species were determined. The radiochemical yields reached 97%. The obtained radiolabeled polymers were stable in blood serum for 3 h. In vivo distribution experiments in intact animals showed the high primary accumulation of technetium-99m MPC (MM = 15,000 Da) in blood with subsequent excretion via the urinary tract.