Biological Evaluation of Thrombus Imaging Agents Utilizing Water Soluble Phosphines and Tricine as Coligands When Used To Label a Hydrazinonicotinamide-Modified Cyclic Glycoprotein IIb/IIIa Receptor Antagonist with ^99mTc

Abstract

A hydrazinonicotinamide-functionalized cyclic glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonist [cyclo(D-Val-NMeArg-Gly-Asp-Mamb(5-(6-(6-hydrazinonicotin amido)hexanamide))) (HYNICtide)] was labeled with 99mTc using tricine and a water soluble phosphine [trisodium triphenylphosphine-3,3',3"-trisulfonate (TPPTS); disodium triphenylphosphine-3,3'-disulfonate (TPPDS); or sodium triphenylphosphine-3-monosulfonate (TPPMS)] as coligands. Three complexes, [99mTc(HYNICtide)(L)(tricine)] (1, L = TPPTS; 2, L = TPPDS; 3, L = TPPMS), were evaluated in the canine arteriovenous shunt (AV shunt) model and canine deep vein thrombosis imaging (DVT) model. All three agents were adequately incorporated into the arterial and venous portions of the growing thrombus (7.8-9.9 and 0.2-3.7% ID/g, respectively) in the canine AV shunt model. In the canine DVT model all three complexes had thrombus uptake that far exceeded the negative control, [99mTc]albumin. The findings indicate similar incorporation into a venous thrombus (% ID/g = 2.86 +/- 0.4, 3.4 +/- 0.9, and 3.38 +/- 1.1 for complexes 1, 2, and 3, respectively) and similar blood clearance with a t1/2 of approximately 90 min. Gamma camera scintigraphy allowed visualization of deep vein thrombosis in as little as 15 min with the thrombus/muscle ratios being 3.8 +/- 0.8, 2.8 +/- 0.4, and 3.0 +/- 0.8 for complexes 1, 2, and 3, respectively. The visualization of the thrombus improved over time, and the thrombus/muscle ratios were 9.7 +/- 1.9, 13.8 +/- 3.6, and 9.4 +/- 2 for complexes 1, 2, and 3, respectively, at 120 min postinjection. The administration of complexes 1-3 did not alter platelet function, hemodynamics, or the coagulation cascade. Furthermore, complexes 1-3 did not significantly differ in their uptake into the growing thrombus, blood clearance, and target to background ratios. Therefore, all three complexes have the capability to detect rapidly growing venous and arterial thrombi.

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

“…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]. A ternary ligand system (HYNIC, tricine, and trisodium triphenylphosphine-3,3¢,3≤-trisulfonate, TPPTS) has been used for the 99m Tc-labeling of chemotactic peptides [35] and leukotriene B 4 (LTB 4 ) receptor antagonists [36][37][38][39] for imaging infection and inflammation, integrin a v b 3 receptor antagonists for tumor imaging [40], and a glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonist for imaging thrombosis [41][42][43][44][45][46]…”

“…A ternary ligand system (HYNIC, tricine, and trisodium triphenylphosphine-3,3¢,3≤-trisulfonate, TPPTS) has been used for the 99m Tc-labeling of chemotactic peptides [35] and leukotriene B 4 (LTB 4 ) receptor antagonists [36][37][38][39] for imaging infection and inflammation, integrin a v b 3 receptor antagonists for tumor imaging [40], and a glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonist for imaging thrombosis [41][42][43][44][45][46][47][48]. The advantage of HYNIC is its high labeling efficiency (rapid and high yield radiolabeling) and the high in vivo stability of the resulting complexes [35][36][37][38][39][40][41][42][43][44][45][46][49][50][51][52]. Since HYNIC can only occupy one or two coordination sites, a coligand such as tricine is needed to complete the coordination sphere of technetium.…”

Coligand effects on the solution stability, biodistribution and metabolism of the 99mTc-labeled cyclic RGDfK tetramer

“…[30]. [53,54], glycoprotein IIB/IIIa receptor antagonist [46], somatostatin analogs [55,56], interleukin-8 [57], and cholecystokinin (CCK8) peptides [58].…”

“…For the last decade, we have been using ternary ligand systems (HYNIC, tricine, water soluble phosphine or pyridine analog) for 99m Tc-labeling of small biomolecules, including chemotactic peptides [40] and LTB 4 antagonists [41,42] for imaging infection/inflammation, integrin α v β 3 antagonists for tumor imaging [27][28][29][30], and a GPIIb/IIIa antagonist for imaging thrombosis [43][44][45][46]. Regardless of the biomolecule, the Tc:HYNIC:L:tricine ratio in [ 99m Tc(HYNIC-biomolecule)(tricine)(L)] always remains 1:1:1:1 as demonstrated via mixed ligand experiments at the tracer level [43,44], and has been further confirmed by the LC-MS data of [ 99m Tc(HYNIC-biomolecule)(tricine)(L)] (L = TPPTS and ISONIC) at both macroscopic and tracer levels [47,48].…”

Towards Developing A Non‐SnCl2 Formulation for RP444, A New Radiopharmaceutical for Thrombus Imaging

“…It was also found that RP444 prepared by this formulation gave excellent images in the canine DVT and arteriovenous (AV) shunt models. 6,7 Injection of the whole or part of the formulation did not cause any unwanted side effects, such as prolonged bleeding time.…”