Synthesis and therapeutic testing of mono- and dialkyl esters of pentetic (diethylenetriaminepentaacetic) acid for decorporation of polymeric plutonium.

The synthesis, characterization, and therapeutic evaluation of a series of partially esterified derivatives of pentetic (diethylenetriaminepentaacetic) acid are reported. These compounds were prepared in an attempt to promote increased decorporation of insoluble colloidal forms of plutonium, which are removed by pentetic acid alone. The dimethyl, diethyl, dibutyl, dioctyl, monoethyl esters were synthesized by reaction of the appropriate alcohol with the dianhydride of pentetic acid. These esters were injected intravenously into mice as their calcium chelates in saline. None of the esters was effective in removing plutonium from the liver. All esters removed approximately 20% of the plutonium in the skeleton. However, when the esters were given together with pentetic acid, only the dioctyl ester showed enhanced removal of plutonium compared to pentetic acid alone. The small increase in effectiveness and the increased acute toxicity make these esters of limited practical interest in plutonium decorporation therapy.