Abstract
This chapter presents methods employed for the synthesis of 18F-fluoromisonidazole tracer for positron emission tomography. The synthetic strategies of fluorine-18 fluoromisonidazole (FMISO) can be divided into two main groups that include a nucleophilic substitution on a protected precursor with subsequent removal of the protection group or epoxide ring-opening, and the production of an 18F-labeled intermediate epifluorohydrin with subsequent coupling to the nitroimidazole moiety under basic conditions. The automated radiochemical synthesis of FMISO is modified from the TracerLab FXF-N through a two-step one-pot procedure that consisted of 18F-fluorination of 1-(2’-nitro-l’-imidazolyl)-2-O-tetrahydropyranyl-3-O-toluenesulphonyl propanediol (NITTP) as the precursor molecule and subsequent hydrolysis of the tetrahydropyranyl (THP)-protected product. The individual synthesis steps involved in the preparation of FMISO can be divided into three main categories. The first category involves fluorination of the precursor, including [18F]fluoride trapped by QMA cartridge, addition of eluent to elute [18F]fluoride from QMA cartridge, drying of [18F]fluoride with acetonitrile, addition precursor solution to reaction vessel, and [18F]fluorination at 100°C for 10 min. The second category involves hydrolysis of the protective group, including evaporation of acetonitrile, addition 1 N HC1 for hydrolysis, and hydrolysis at 100°C for 5 min. The third category involves neutralization/HPLC and formulation. Synthesis of FMISO is carried out by a two-pot automated synthesis procedure via Sep Paks separation on an automated [18F]fluorodeoxyglucose (FDG) synthesis module made by IBA. The uncorrected radiochemical yield is 21% on average, the radiochemical purity is >97%, and the total synthesis time is ∼50 min. Synthesis of FMISO is also performed by a one-pot automated synthesis procedure via HPLC separation at the TracerLab Mx FDG synthesis module.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call