Synthesis and characterization of well-defined l-lactic acid-caprolactone co-oligomers and their rhenium (I) and technetium(I) conjugates

Staring from l-lactide and ε-caprolactone, the corresponding lactic-caprolactone cooligomer with hydroxyl and carboxylic acid groups were synthesized. These oligomers were connected with chelating groups through a long chain tether, ready for transition metal binding. Coordination of organometallic rhenium(I) and technetium(I) complexes generated the conjugates in high yield and short time, satisfying the requirements for short-lived radiopharmaceuticals in clinical applications. A reasonable pharmacophore model has been established to guide the design of well-defined lactic acid oligomer for nuclear medicine.

We prepared molecularly defined LA-CL oligomers with terminal functional groups. These oligomers were connected with chelating groups through a long chain tether. Coordination of organometallic rhenium(I) and technetium(I) complexes generated the conjugates in high yield and short time, satisfying the requirements for radiopharmaceuticals in clinical applications.Figure optionsDownload as PowerPoint slideHighlights
► Molecularly defined LA-CL cooligomer with –OH or –COOH groups were synthesized.
► The LA-tridentate-Re(I) complexes were synthesized and fully characterized.
► 99mTc(I) labeled LA conjugates was synthesized in a short time, and a high yield.
► The 99mTc(I)-LA maintain excellent in vitro stability in PBS.