Pentetate calcium trisodium is also known as trisodium calcium diethylenetriaminepentaacetate and is commonly referred to as Ca-DTPA is indicated for treatment of individuals with known or suspected internal contamination with plutonium, americium, or curium to increase the rates of elimination. It is a white, water-soluble solid. It has a molecular formula of Na3CaC14H18N3O10 and a molecular weight of 497.4 Daltons. Ca-DTPA is supplied as a clear, colorless, hyperosmolar (1260 mOsmol/kg) solution in a colorless ampoule containing 5 mL. The ampoule contents are sterile, non-pyrogenic and suitable for intravenous administration. Each mL of solution contains the equivalent of 200 mg pentetate calcium trisodium (obtained from 158.17 mg pentetic acid, 40.24 mg calcium carbonate and NaOH) in water for injection, USP. The pH of the solution is adjusted with NaOH and is between 7.3 - 8.3. Ca-DTPA forms stable chelates with metal ions by exchanging calcium for a metal of greater binding capacity. The radioactive chelates are then excreted by glomerular filtration into the urine. In animal studies, Ca-DTPA forms less stable chelates with uranium and neptunium in vivo resulting in the deposition of these elements in tissues including the bone. The Food and Drug Administration (FDA) has determined that PENTETATE CALCIUM TRISODIUM (trisodium calcium diethylenetriaminepentaacetate (Ca-DTPA)) solution for intravenous or inhalation administration, equivalent to (EQ) 1 gram (g) base/5 milliliters (mL) (EQ 200 milligrams (mg) base/mL) was not withdrawn from sale for reasons of safety or effectiveness. This determination will allow FDA to approve abbreviated new drug applications (ANDAs) for PENTETATE CALCIUM TRISODIUM (Ca-DTPA) solution for intravenous or inhalation administration (EQ 1 g base/5 mL (EQ 200 mg base/mL)), if all other legal and regulatory requirements are met. Ca-DTPA treatments are not expected to be effective for uranium and neptunium. Radioactive iodine is not bound by DTPA