Synthesis and evaluation of 7α-(3-[18F]fluoropropyl) estradiol

PET Imaging of Steroid Hormone Receptor Expression

“…The in vivo biodistribution study showed that C3-7α-[ 18 F]FES was selectively taken into the uterus with reversible kinetics. 27 The level of C3-7α-[ 18 F]FES uptake was significantly lower than that of 16α-[ 18 F]FES, but receptor specificity was determined by dose-dependent inhibition of C3-7α-[ 18 F]FES uptake with estradiol coinjections. Defluorination of C3-7α-[ 18 F]FES was speculated by gradual increase in bone radioactivity.…”

“…Okamato and colleagues synthesized 7-(3-[ 18 F]fluoropropyl) estradiol (C3-7-[ 18 F]FES) and evaluated its potential for detecting ER expression in vitro and in vivo (Figure 3). 27 The radiosynthesis of C3-7-[ 18 27 Although C3-7-[ 18 F]FES exhibited favorable receptor specificity, in vivo defluorination of this radioligand led to increased uptake of radioisotope in bone, which is likely to have confounding effects on receptor quantification. Further optimization of this radioligand is required so that receptor specificity is maintained and in vivo defluorination is reduced.…”

“…Okamato and colleagues synthesized 7α-(3-[ 18 F]fluoropropyl) estradiol (C3-7α-[ 18 F]FES) and evaluated its potential for detecting ER expression in vitro and in vivo (Figure 3). 27 The radiosynthesis of C3-7α-[ 18 F]FES was achieved from a tosylated precursor using [ 18 F]KF/Kryptofix 222 with an RCY of 30.7% ± 15.1% (decay corrected), and a specific activity of 32.0 ± 18.1 GBq/umol was achieved. 27 The binding affinity of C3-7α-[ 18 F]FES was determined in vitro and was comparable to that of 16α-[ 18 F]FES.…”

“…27 The radiosynthesis of C3-7α-[ 18 F]FES was achieved from a tosylated precursor using [ 18 F]KF/Kryptofix 222 with an RCY of 30.7% ± 15.1% (decay corrected), and a specific activity of 32.0 ± 18.1 GBq/umol was achieved. 27 The binding affinity of C3-7α-[ 18 F]FES was determined in vitro and was comparable to that of 16α-[ 18 F]FES. The in vivo biodistribution study showed that C3-7α-[ 18 F]FES was selectively taken into the uterus with reversible kinetics.…”

Prototypic 18F-Labeled Argininamide-Type Neuropeptide Y Y1R Antagonists as Tracers for PET Imaging of Mammary Carcinoma

“…28 Likewise, acylation of 14 with 2-fluoropropionic acid gave 23, the compound with the highest Y 1 R affinity (K i = 1.3 nM) among the fluorinated ligands. Acylation of the guanidine group in 1a with 4-fluorobenzoic acid, affording 7, and the introduction of N ω -alkoxycarbonyl substituents (35,36) resulted in compounds with considerably decreased Y 1 R affinity (Table 1). Even though alkyne derivative 39 showed high Y 1 R binding (K i = 1.3 nM), the glucosylated derivative 41 exhibited significantly decreased Y 1 R affinity (K i = 2.0 μM).…”