Novel estradiol based metal complexes of Tc-99m

Aiming to contribute to the design of technetium imaging agents for estrogen receptor (ER) positive breast tumors, we have synthesized and evaluated the novel organometallic estradiol complexes (fac-[M(CO)3(κ3-10)]+ and fac-[M(CO)3(κ3-12) M = Re/99mTc) using two different bifunctional tridentate ligands (4 and 8). The rhenium complexes (13 and 14) were fully characterized by IR, 1H NMR, 13C NMR, mass spectrometry and elemental analyses. The 99mTc complexes (15 and 16) were obtained with high radiochemical purity and exhibited high in vitro radiochemical stability. To get a first insight into the relevance of these complexes for targeting ER positive tumors, ER binding affinity assays and cellular internalization studies in an ER expressing cell line, MCF-7, have also been performed suggesting a non ER mediated uptake.

Aiming to contribute for the design of technetium based radiotracers as molecular probes for the estrogen receptor, we have prepared and radiochemically and biologically evaluated two novel Re(I)/99mTc(I)-complexes containing 17α-substituted estradiol derivatives.Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of tricarbonyl complexes bearing different charge and donor atom sets.
► Novel organometallic Re/99mTc estradiol complexes were prepared.
► 99mTc complexes with high radiochemical purity and in vitro stability.
► Cellular/nuclear internalization studies of estradiol based complexes of Tc-99m.