Synthesis and evaluation of fluorine-18 labelled compounds for imaging of bacterial infections with pet

Comparison of 99mTc- and 18F-Ubiquicidin Autoradiography to Anti–Staphylococcus aureus Immunofluorescence in Rat Muscle Abscesses

“…The binding correlated partly with 3 H-DG accumulation, but the pattern of uptake was not consistent with macrophage infiltration, indicating unspecific binding of the UBI derivatives. Unspecific binding of 99m Tc-UBI 29-41 has also been reported in 1 patient with soft-tissue inflammation in whom cultures were negative for bacteria (8). On the basis of our evaluations of tissue staining, we are at present unable to provide a consistent hypothesis for the mechanisms of unspecific binding of the UBI derivatives.…”

“…99m Tc-labeling of UBI 29-41 (Thr-Gly-Arg-Alu-Lys-Arg-MetGln-Tyr-Asn-Arg-Arg) was mediated via complexation with 99m Tc-sodium pertechnate (6) and 18 F labeling of UBI 29-41 and UBI 28-41 via chemical connection of N-succinimidyl-4-18 Ffluorobenzoate and the lysine group of UBI as described previously (8). Both compounds had a specific activity of more than 35 TBq/mmol.…”

The Pharmacology of Radiolabeled Cationic Antimicrobial Peptides

“…Peptide synthesis also allows the production of chemical variants, such as D-enantiomers which are less easily degraded by enzymatic decomposition, peptides that have amino acid substitutions at various positions, and incorporation of various linkers at desired places in order to change its pharmacology or to incorporate markers. 26,27 The study of different domains of native molecules may result in the identification of biologically active regions, for example, those ones in antimicrobial cationic peptides which are responsible for binding and killing the target. Eventually, this knowledge and techniques can be used to select peptide fragments that preferentially bind to specific species of pathogens and show favorable pharmacologic behavior for scintigraphic imaging.…”

“…[29][30][31] Recently, the solid phase synthesis of 18 F-labeled linear peptides enabled positron emission tomography (PET) with labeled peptides. 27,32 Because of its favorable radiation characteristics, easy radiopharmacy, and ready availability, 33 99m Tc is the preferred label to determine the pharmacokinetics of cationic antimicrobial peptides as described in this review.…”

“…Encouraging findings by colleagues using the PET tracer fluorine-18 synthesized UBI 29-41 confirmed the specific binding of this tracer to bacteria. 27 Moreover, they concluded that UBI 29-41 fulfils the criteria as the ideal tracer for detecting infections.…”