Radiochemical Characterization of 67,68Ga Labeled DOTA Derivatives

Hung-Jen Huang; Jem-Mau Lo

doi:10.6180/jase.2003.6.1.03

Radiochemical Characterization of 67,68Ga Labeled DOTA Derivatives

Chemical Engineering

Hung-Jen Huang¹ and Jem-Mau Lo ¹

¹Department of Nuclear Science National Tsing Hua University Hsinchu, Taiwan 300, R.O.C

Received: January 7, 2003
Accepted: February 7, 2003
Publication Date: March 1, 2003

Download Citation: ||https://doi.org/10.6180/jase.2003.6.1.03

ABSTRACT

C-aryl derivatives of DOTA (N,N’,N”,N”’-tetrakis(carboxymethyl)- 1,4,7,10-tetraazacyclododecane) including phenyl-DOTA and 3-NO2- Ph-DOTA were synthesized by a template reductive reaction. 67GaCl3 or 68GaCl3 was taken and transformed into 67,68Ga-acetylacetone ( ^67,68Ga(acac)3) before labeling to the DOTA derivatives. The ⁶⁷Ga or ⁶⁸Ga labeled complexes were generated by ligand-ligand exchange of acetylacetonate with the DOTA derivatives. The labeling efficiency of PhDOTA with ^67,68Ga could be higher than 95% under the reaction being facilitated via sonication, at ambient temperature for 20 min. By a similar reaction, the labeling efficiency of 3-NO2-Ph-DOTA with ^67,68Ga was found to be lower (~ 40%). The stability of 67Ga-Ph-DOTA was high, maintaining at ≥ 98% yield even at 24 h post-preparation. The 68Ga labeled Ph-DOTA complex was radiochemically characterized to be anionic and hydrophilic. It is anticipated from the result that 68Ga in the form of Ga(III) may be six coordinated with Ph-DOTA by 4N from the ring and 2O from two of four pendent acetic groups, leaving other two acetic groups uncoordinated.

Keywords: 67Ga, 68Ga, DOTA, 67,68Ga-DOTA Derivatives, RadioChemical Characterization

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