Synthesis and properties of neutral gadolinium and technetium-99m-labeled complexes

Abstract

Diethylenetriaminepentaacetic di(L-dopa ethyl ester) ligand (DTPA-2LDEE) was synthesized by reaction between diethylenetriaminepentaacetic dianhydride (DTPAA) and L-dopa ethyl ester (LDEE). This ligand reacted with gadolinium chloride and sodium pertechnetate to make the corresponding neutral gadolinium complex Gd-DTPA-2LDEE and technetium-99m-labeled complex ^99mTc-DTPA-2LDEE, respectively. The ligand and complexes were characterized and their properties in vitro and in vivo were also evaluated. Gd-DTPA-2LDEE possessed higher relaxation effectiveness and lower cytotoxicity to human hepatoma HepG-2 cells than Gd-DTPA. ^99mTc-DTPA-2LDEE had enhanced single-photon emission computed tomography (SPECT) signal enhancements of the kidneys in rats and provided longer duration time than that of ^99mTc-DTPA. Therefore, ^99mTc-DTPA-2LDEE can be selectively excreted by the kidneys and used as a potential radioactive probe in SPECT.

Graphical Abstract

Keywords:

• Single-photon emission computed tomography (SPECT)
• Magnetic resonance imaging (MRI)
• Gadolinium complex
• Technetium-99m-labeled complex
• Diethylenetriaminepentaacetic acid
• L-dopa ethyl ester

Funding

We thank the National Natural Science Foundation of China [grant number 51173140], [grant number 51373128]; Wuhan Scientific and Technological Project, Hubei Province [grant number 2013010501010131]; Key Science Foundation of Hubei Province [grant number 2009CDA052]; National Student Innovation and Enterprise Training Project in Local University [grant number 201310490011], [grant number 201210490007], [grant number 201210490021]; and Innovation Fund for post-graduate education [grant number CX201231], [grant number CX2013083]; Wuhan Institute of Technology, China.