No‐carrier‐added labeling of the neuroprotective Ebselen with selenium‐73 and selenium‐75

Abstract

Selenium-73 is a positron emitting non-standard radionuclide, which is suitable for positron emission tomography. A copper-catalyzed reaction allowed no-carrier-added labeling of the anti-inflammatory seleno-organic compound Ebselen with (73) Se and (75) Se under addition of sulfur carrier in a one-step reaction. The new authentically labeled radioselenium molecule is thus available for preclinical evaluation and positron emission tomography studies.

Target development for diversified irradiations at a medical cyclotron

“…The production of 120 I, 124 I and 75 Se was based on adaptation of the established technology for those radionuclides (cf. Qaim et al, 2003;Blessing et al, 1994) but the applications mentioned here are the newest, demonstrating typical utilizations of the present products (Herzog et al, 2008;Shah et al, 2014;Helfer et al, 2015). The production methodologies for 52 Mn, 76 Br and 48 V are new developments (cf.…”

Labelling with positron emitters of pnicogens and chalcogens

“…On transferring the conditions to the radiosyntheses with the positron emitter 73 Se, however, nca [ 73 Se]ebselen could only be obtained with an RCY of 22% (cf Scheme 11). 34…”

“…A possible disadvantage of 73 Se is its radioactive daughter arsenic‐73 (decay mode: EC; half‐life: 80.3 d). The contribution of this rather long‐lived decay product to the radiation dose is not yet determined and depends on the individual kinetics of the 73 Se tracer applied, as well as on those of the decay‐generated chemical forms of arsenic at the nca level, which has a strong influence on the excretion …”

“…After optimization of reaction parameters, nca [ 75 Se]ebselen could be synthesized with RCYs of 55% within 3 hours. On transferring the conditions to the radiosyntheses with the positron emitter 73 Se, however, nca [ 73 Se]ebselen could only be obtained with an RCY of 22% (cf Scheme ) …”