One-Pot Two-Step Radiosynthesis of a New 18F‑Labeled Thiol Reactive Prosthetic Group and Its Conjugate for Insulinoma Imaging
BibTeX
@MISC{Kiesewetter_one-pottwo-step,
author = {Dale O. Kiesewetter and Xiaoyuan Chen},
title = {One-Pot Two-Step Radiosynthesis of a New 18F‑Labeled Thiol Reactive Prosthetic Group and Its Conjugate for Insulinoma Imaging},
year = {}
}
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Abstract
ABSTRACT: N-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-ethyl)-6-fluoronicotinamide ([18F]FNEM), a novel prosthetic agent that is thiol-specific, was synthesized using a one-pot two-step strategy: (1) 18F incorporation by a nucleophilic displacement of trimethylammonium substrate under mild conditions; (2) amidation of the resulting 6-[18F]-fluoronicotinic acid 2,3,5,6-tetrafluorophenyl ester with N-(2-aminoethyl)maleimide trifluoroacetate salt. The radiosynthesis of the maleimide tracer was completed in 75 min from [18F]fluoride with 26 ± 5 % decay uncorrected radiochemical yield, and specific activity of 19−88 GBq/μmol (decay uncorrected). The in vitro cell uptake, in vivo biodistribution, and positron emission tomography (PET) imaging properties of its conjugation product with [Cys40]-exendin-4 were described. [18F]FNEM-Cys40-exendin-4 showed specific targeting of glucagon-like peptide 1 receptor (GLP-1R) positive insulinomas and comparable imaging results to our recently reported [18F]FPenM-Cys40-exendin-4.
