Preparation of hydrazino-modified proteins and their use for the synthesis of technetium-99m-protein conjugates

Abstract

The syntheses and protein linking properties of succinimidyl 4-hydrazinobenzoate hydrochloride (SHBH) and succinimidyl 6-hydrazinonicotinate hydrochloride (SHNH), two new heterobifunctional linkers which lead to hydrazino-modified proteins, are described. SHBH-modified proteins are unstable due to the presence of the phenylhydrazine moiety. This problem was overcome by synthesizing the hydrazinopyridine analogue SHNH, and the conjugates derived from this linker are stable. Tc(V) oxo precursors readily add to hydrazinopyridine-modified proteins to yield the desired 99mTc-radiolabeled protein. 99mTc-hydrazinopyridine-polyclonal IgG conjugates are useful agents for the imaging of focal sites of infection.

6-Hydrazinonicotinamide Derivatives as Bifunctional Coupling Agents for 99mTc-Labeling of Small Biomolecules

“…It was found that the combination of XV120 with tricine and a phosphine coligand results in a versatile ternary ligand system that forms 99m Tc 6-Hydrazinonicotinamide Derivatives as Bifunctional Coupling Agents 121 Fig. 2 Structures of coligands and their ternary ligand 99m Tc complexes. The combination of HYNIC, tricine, and a phosphine or pyridine analog results in a versatile ternary ligand system that forms ternary ligand 99m Tc complexes with extremely high stability complexes, [ 99m Tc(XV120)(tricine)(L)] (Scheme 1: RP444, L is TPPTS; RP445, L is TPPDS; RP446, L is TPPMS) in high yield and high specific activity 20,000 Ci/mmol and greater).…”

“…For example, it has been reported that tricine gives a much higher specific activity for the 99m Tc-labeled HYNIC-IgG than GH [1,2,55]. Tricine also gives a higher specific activity for the 99m Tc-labeled HYNIC-BM than EDDA analogues [42].…”

“…Abrams and coworkers [1,2] first reported the use of aromatic hydrazines, including 6-hydrazinonicotinamide (HYNIC), as bifunctional coupling agents (BFCs) for the 99m Tc-labeling of polyclonal IgG for imaging inflammation and infection diseases. Since then, the HYNIC technology has successfully been used for the 99m Tc-labeling of antibodies [3][4][5][6][7][8] and small biomolecules (BMs), including chemotactic peptides [9][10][11][12][13][14][15][16][17][18], somatostatin analogs [19][20][21][22][23][24][25],"stealth" liposomes [26,27], antisense oligonucleotides [28][29][30][31], a folate receptor ligand [32], and polypeptides [32][33][34].…”

Technetium-binding in labelled HYNIC-peptide conjugates: Role of coordinating amino acids

“…1) as a bifunctional linker for labelling biomolecules with 99m Tc [1][2][3][4][5], it has proven to be exceptionally efficient and has become widely used, with many applications and refinements being reported [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. HYNIC is typically [7,[20][21][22][23] used in the form of an activated ester, and conjugated to a peptide by reaction with the N-terminal amine group.…”

Radiopharmaceuticals for somatostatin receptor imaging

“…It has initially been developed for radiolabeling of polyclonal immunoglobulin [33], and was then recommended for preparation of hydrazino-modified proteins and synthesis of 99m Tc-protein conjugates [34] and chemotactic peptides [35] and HYNIC as bifunctional chelator (BFC) was introduced for 99m Tc labeling of octreotide and TOC (Tyr 3 -octreotide) with high efficiency [36,37].…”