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Synthesis, characterization, and biological evaluation of new biotinylated 99m Tc/Re‐tricarbonyl complexes
Author(s) -
Makris George,
Papagiannopoulou Dionysia
Publication year - 2016
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.3372
Subject(s) - chemistry , biodistribution , propanoic acid , avidin , carboxylate , biotinylation , amine gas treating , stereochemistry , biotin , cysteine , histidine , amino acid , in vitro , organic chemistry , biochemistry , enzyme
The synthesis and biological evaluation of three new biotinylated fac ‐[ 99m Tc/Re(CO) 3 ] + complexes with the tridentate ligands L1, L2, and L3 are reported. L1–L3 contain the chelators 2‐((5‐aminopentyl)(pyridin‐2‐ylmethyl)amino)acetic acid, 2‐(2‐aminoethylthio)‐3‐(1 H ‐imidazol‐4‐yl)propanoic acid, and 2‐amino‐3‐(1‐carboxy‐2‐(1 H ‐imidazol‐4‐yl)ethylthio)propanoic acid, respectively, which are conjugated to biotin's carboxylate via their amine group. The fac ‐[Re(CO) 3 (L1–L3)] complexes were synthesized and characterized by NMR and IR, where the (N,N,O) coordination for ReL1 and the (N,S,O) coordination for ReL2 and ReL3 were confirmed. The tracer complexes fac ‐[ 99m Tc(CO) 3 (L1–L3)] were synthesized in high yield and were found highly stable in 10 −3 M l ‐histidine and l ‐cysteine over 24 h. Furthermore, they exhibited high binding affinity (>90%) for avidin. Rat plasma studies showed complete cleavage of biotin from 99m TcL1 after 1 h and a low percentage of intact 99m TcL2 and 99m TcL3 with no biotin cleavage metabolites present, over 24 h. Similarly, rat urine analysis showed the presence of intact 99m TcL2 and 99m TcL3, while 99m TcL1 was cleaved. Biodistribution studies of 99m TcL2 and 99m TcL3 revealed fast blood and tissue clearance.