Synthesis and basic evaluation of 7α-(3-[18F]fluoropropyl)-testosterone and 7α-(3-[18F]fluoropropyl)-dihydrotestosterone

Abstract

[F]15 is better than [F]7 in terms of radiochemical yield, in vitro binding affinity, prostate specific binding and stability against in vivo metabolic de-fluorination. However, the net uptake level of [F]15 in prostate might be insufficient for in vivo visualization. Although [F]7 and [F]15 improved in vivo stability against de-fluorination, other basic characterization data in rodents were not superior to the current standard tracer 16β-[F]fluoro-5α-dihydrotestosterone. It is also revealed that the shorter side chain length of 7α-[F]fluoromethyl-dihydrotestosterone is superior to the longer three carbon chain in [F]15, in terms of net prostate uptake and in vivo metabolic stability.