Orally administered DTPA di-ethyl ester for decorporation of ²⁴¹Am in dogs: Assessment of safety and efficacy in an inhalation-contamination model

Abstract

Purpose: Currently two injectable products of diethylenetriaminepentaacetic acid (DTPA) are U.S. Food and Drug Administration (FDA)-approved for decorporation of ²⁴¹Am; however, an oral product is considered more amenable in a mass casualty situation. The di-ethyl ester of DTPA, named C2E2, is being developed as an oral drug for treatment of internal radionuclide contamination.

Materials and methods: Single-dose decorporation efficacy of C2E2 administered 24-h post contamination was determined in beagle dogs using a ²⁴¹Am nitrate inhalation contamination model. Single and multiple dose toxicity studies in beagle dogs were performed as part of an initial safety assessment program. In addition, the genotoxic potential of C2E2 was evaluated by the in vitro bacterial reverse mutation Ames test, mammalian cell chromosome aberration cytogenetic assay and an in vivo micronucleus test.

Results: Oral administration of C2E2 significantly increased ²⁴¹Am elimination over untreated controls and significantly reduced the retention of ²⁴¹Am in tissues, especially liver, kidney, lung and bone. Daily dosing of 200 mg/kg/day for 10 days was well tolerated in dogs. C2E2 was found to be neither mutagenic or clastogenic.

Conclusions: The di-ethyl ester of DTPA (C2E2) was shown to effectively enhance the elimination of ²⁴¹Am after oral administration in a dog inhalation-contamination model and was well tolerated in toxicity studies.

Keywords::

• Americium
• alpha emitters
• DTPA
• decorporation
• radionuclides

Declaration of interest

Drs Jay and Mumper are co-founders of Capture Pharmaceuticals, which owns intellectual property related to C2E2. However, no financial support from Capture Pharmaceuticals was provided in these studies. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.