Synthesis of high specific activity [75Br]- and [77Br]bromperidol and tissue distribution studies in the rat

Abstract
A rapid synthesis of [75Br]-and [77Br]bromperidol with specific activity exceeding 10,000 Ci/mmol is described in which a trimethylstannylated analog of bromperidol is used as a substrate for regiospecific no-carrier-added radiobromination. 4-[4-[4-(Trimethylstannyl)phenyl]-4-hydroxypiperidino]-4''-fluorobutyrophenone was synthesized by the reaction of (trimethylstannyl) sodium with haloperidol and purified by preparative HPLC [high-performance liquid chromatography]. Subsequent radiobromination with no-carrier-added 75Br- or 77Br- and in situ oxidation using H2O2/CH3COOH gave a corrected radiochemical yield of 35% with a 30 min preparation time. Tissue distribution studies in the rat show a rapid and prolonged uptake into the brain, liver and kidneys, and consistently low blood concentrations that differ quantitatively from previous studies using relatively low specific activity bromperidol. Potential clinical applications for this high specific activity radiobrominated neuroleptic are discussed.