Retracted: Synthesis, Characterization, and Preclinical Evaluation of ^99mTc‐Labeled Macrobicyclic and Tricyclic Chelators as Single Photon Emission Computed Tomography Tracer

Abstract

The novel tetraaza macrobicyclic chelator 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-2,10-dione (TBPD) and pentaaza macrotricyclic chelator 9-oxa-3,6,12,15,21-pentaazatricyclo[15,3,2,1]trieicos-1(21),17,19-triene-2,7,11,16-tetradione (OPTT) were synthesized, characterized, and radiolabeled with (99m)Tc to produce (99m)Tc-TBPD and (99m)Tc-OPTT. These radiolabeled complexes were prepared with high radiolabeling yield, radiochemical purity, and good in vitro stability up to 24 h. The labeling efficiency of (99m)Tc-TBPD and (99m)Tc-OPTT was found 98% and 97%. In vitro serum stability of (99m)Tc-TBPD was found to be 95.2%, while that of (99m)Tc-OPTT 94.2% up to 24 h. Blood kinetics experiments of (99m)Tc-labeled complexes showed biphasic pattern of blood clearance. About 99.57 ± 0.89% activity of (99m)Tc-TBPD and 99.42 ± 0.88% activity of (9m)Tc-OPTT were cleared off blood stream at 24 h postadministration. The biological half-life of (99m) Tc-TBPD was observed: t1/2(F) 1 h 5 min and t1/2(S) 12 h and biological half-life of (99m)Tc-OPTT was observed: t1/2(F) 1 h 10 min and t1/2(S) 9 h 50 min, respectively. The biodistribution studies revealed that maximum uptake of (99m)Tc-TBPD was found in liver, concluded that excretory pathway is hepatobiliary, while that of (99m)Tc-OPTT was renal as well as hepatobiliary. The negligible activity observed in stomach confirming the stability of radiolabeled complex in biological milieu. In vitro cytotoxicity study of TBPD and OPTT did not show any considerable antiproliferative activity against cancer cells of human cervical SW756, HeLa, and glioblastoma U-87, U373 cell lines.

New Insights in the Design of Bioactive Peptides and Chelating Agents for Imaging and Therapy in Oncology

“…Tetraazamacrocycle derivatives are widely studied as bifunctional chelating agents for conjugating different biomolecules with radionuclides in target-specific radiotherapy. The novel tetraazamacrobicyclic chelator 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-2,10-dione (TBPD) and pentaazamacrotricyclic chelator 9-oxa-3,6,12,15,21-pentaazatricyclo[15,3,2,1] trieicos-1(21), 17,19-triene-2,7,11,16-tetradione (OPTT) ( Figure 2 ) were synthesized and radiolabeled with 99m Tc to produce 99m Tc-TBPD and 99m Tc-OPTT [ 94 ]. These radiolabeled complexes showed high yield, purity, labeling efficiency and in vitro stability.…”

Synthesis and preliminary evaluation of a 99mTc‐labeled folate‐PAMAM dendrimer for FR imaging

“…The UV spectroscopy was measured by using microplate spectrophotometer (Multiskan GO, Thermo Fisher, USA). 1 HNMR spectra were measured on a Bruker (600 MHz) spectrometer. Chemical shifts are reported in δ (ppm) values.…”

“…Nuclear medicine relies on collaboration of radiopharmaceuticals and nuclear medicine technologies. Substantial effort has been focused on the development of molecular probes to achieve tumor‐specific therapeutic and diagnostic agents . Antibody, sugar, folic acid (FA), transferrin, epidermal growth factor, and Arg–Gly–Asp peptide are tumor targeting ligands used to give an active targeting ability to drug carriers .…”

“…Substantial effort has been focused on the development of molecular probes to achieve tumor-specific therapeutic and diagnostic agents. [1] Antibody, sugar, folic acid (FA), transferrin, epidermal growth factor, and Arg-Gly-Asp peptide are tumor targeting ligands used to give an active targeting ability to drug carriers. [2,3] Of these ligands, FA has attracted wide attention because of its high stability, low cost, non-immunogenic character, low molecular weight, and simple chemical modification.…”

Supramolecular networks and Hirshfeld surfaces of oxydiacetic acid and iminodiacetic acid salts

“…Wen et al (2006) reported the crystal structure of N,N 0 -bis(4-methoxyphenyl)-3-oxapentanediamide which was synthesized using oxydiacetic acid and p-methoxyaniline. A macrotricyclic compound containing oxydiacetic acid moiety was synthesized and radiolabelled with 99m Tc, which provided a platform for the development of imaging agents and the diagnosis of tumour cells (Yadav et al, 2016). Yasodhai & Govindarajan (2000) reported the synthesis and thermal study of hydrazinium oxydiacetate.…”