Simplified and automatic one-pot synthesis of 16alpha-(~(18)F)fluoroestradiol without high-performance liquid chromatography purification

摘要

16alpha-[~(18)F]Fluoroestradiol (16alpha-[~(18)F]FES, 1) is known as a valuable tracer in molecular imaging as estrogen receptor (ER) ligand for investigation of primary and metastatic breast cancer. ER concentration in human breast tumor cells is a significant indicator for the degree of disease and is often monitored by immunoassays or in vitro ligand binding of a tumor biopsy sample. More preferable non-invasive diagnosis is accessible using 16alpha-[~(18)F]FES (1) as PET tracer. Our aim was to develop a reliable, easy-to-use, remotely controlled synthesis for non carrier added (n.c.a.) 16alpha-[~(18)F]FES (1) by nucleophilic substitution using a disposable cassette for GE TRACERlab~R MX_(FDG). Purification of the crude product using solid phase extraction (SPE) cartridges. Oasis~R WAX, HLB Plus, Sep-Pak~R C18 and Light Alumina N, allows abandonment of an HPLC purifying system. Formulation of the final product is included in the automatic synthesis. The experimental conditions for this easy-to-use synthesis for routine production of 16alpha-[~(18)F]FES (1) are given in detail. Within 75 min 16alpha-[~(18)F]FES (1) is produced in typically 20% n.c.a., radiochemical yield (non decay corrected). Chemical and radiochemical purity is >95% and >99%, respectively.