Technetium coordination ability of cysteine-containing peptides: X-ray absorption spectroscopy of a 99Tc labelled endothelin derivative

99mTc-Labeled Small Peptides as Diagnostic Radiopharmaceuticals

“…It also contains a technetium chelating group (KCTCCA). The animal studies showed that 99m Tc−CYT-379 preferentially localizes in fresh thrombi in rabbits and dogs 1−2 h postinjection . A phase I clinical study showed that 99m Tc−CYT-379 has an initial component of rapid clearance with t 1/2 α of 12 min, followed by a slow component with t 1/2 β = 160 min.…”

“…It was also found that 99m Tc−CYT-379 has a low sensitivity and accuracy (43%, 3/7) in detecting thrombi in patients, particularly those who were receiving heparin at the time of administration of 99m Tc−CYT-379. The low sensitivity and accuracy of 99m Tc−CYT-379 was also attributed to its slow clearance from blood plasma and the partial heptabilary excretion …”

“…The animal studies showed that 99m Tc-CYT-379 preferentially localizes in fresh thrombi in rabbits and dogs 1-2 h postinjection. 390 A phase I clinical study showed that 99m Tc-CYT-379 has an initial component of rapid clearance with t 1/2 R of 12 min, followed by a slow component with t 1/2 β ) 160 min. It was also found that 99m Tc-CYT-379 has a low sensitivity and accuracy (43%, 3/7) in detecting thrombi in patients, particularly those who were receiving heparin at the time of administration of 99m Tc-CYT-379.…”

“…The low sensitivity and accuracy of 99m Tc-CYT-379 was also attributed to its slow clearance from blood plasma and the partial heptabilary excretion. 390 Other 99m Tc-labeled receptor ligands for thrombus imaging include TP-1300 (CSVTCR), 391 snake venom peptides, 392,393 and MP-2026 (Thromboscan), 394 which is an N 3 S-conjugated RGD peptidomimetic analogue. TP-1300 was modified with an N 4 Gly-Ala-Gly-Gly binding group for 99m Tc-labeling and an Aba (2,4diaminobutanoic acid) linker.…”

Structural Study by NMR of an Oxorhenium−RGD Decapeptide Complex for Application in Radiotherapy

“…It is known that cysteine acts as a bidentate chelator and coordinates to oxotechnetium and oxorhenium cores both through the sulfur and the amide nitrogen. [10][11][12] Thus, it was reasonable to propose that the decapeptide coordinates to the oxorhenium core through the In the proposed structure, the RGDSCRGDSY ligand complexes with ReO(V) 3+ via three deprotonated amide nitrogen atoms and one deprotonated thiol sulfur atom and the ReO(V) 3+ binding region is expected to carry a negative charge. The proposed structure of complex 1 is similar to the well-known structure of 99m TcO-mercaptoacetyltriglycine ( 99m TcO-MAG 3 ), the standard radiopharmaceutical in commercial use for renal imaging, 13 in which the oxotechnetium core binds to the three deprotonated glycine amide nitrogen atoms and to the thiol sulfur atom to form a stable, negatively charged complex of the TcO[N 3 S] type and of its oxorhenium analogue.…”