A NEW EFFICIENT METHOD FOR THE PREPARATION OF TC-99M-RADIOPHARMACEUTICALS CONTAINING THE TCN MULTIPLE BOND

An improved method for the preparation of Tc-99m-radiopharmaceuticals containing the Tc=N multiple bond, in sterile and apyrogen conditions, is described. This method is based on the reaction of [Tc-99m]pertechnetate with ligands derived from S-methyl dithiocarbazate [H2N-N(R)-C(=S)SCH3 (R = H, CH3], in the presence of HCl and tertiary phosphines. It was found that these derivatives can behave both as sources of nitride nitrogen ions (N-3-) and as coordinating ligands. The reaction leads to the formation of intermediate technetium-nitrido complexes in high yield. These intermediate species can be used as suitable prereduced substrates for the preparation of technetium-nitrido radiopharmaceuticals through simple substitution reactions with appropriate exchanging ligands.