Synthesis and Characterization of Gadolinium Diethylenetriamine Pentaacetate-Folate☆

In our preliminary radiopharmaceutical study, ¹⁵³Gd-DTPA-Folate has been successfully prepared, and tested for its bio-distribution. This continuing study is aimed at synthesizing and characterizing Gd-DTPA-Folate. The synthesis was started with the preparation of a derivative of folic acid, EDA-Folate, which was subsequently reacted with DTPA-Dianhydride to form DTPA-Folate. Finally, DTPA-Folate was reacted with Gd³⁺ to result in Gd-DTPA-Folate, on a 0.1-10 gram scale, with a yield of 97.2%. Experimental data collected from characterization of purified synthetic products using ultraviolet, infrared, and mass spectroscopy, indicated the formation of Gd-O and Gd-N bonds leading to the formation of Gd-DTPA-Folate molecule.