Pentetic acid
From Wikipedia, the free encyclopedia
| DTPA | |
|---|---|
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| IUPAC name | [[(Carboxymethyl)imino]bis(ethylenenitrilo)]- tetra-acetic acid |
| Other names | DTPA, Diethylene triaminepentaacetic acid,
Diethylenetriamine- N,N,N',N',N"-pentaacetic acid, N,N-Bis(2-(bis-(carboxymethyl)amino)ethyl)-glycine, Pentetic acid |
| Identifiers | |
| CAS number | [67-43-6] |
| RTECS number | MB8205000 |
| SMILES | O=C(O)CN(CCN(CC(=O)O)CC (=O)O)CCN(CC(=O)O)CC(=O)O |
| Properties | |
| Molecular formula | C14H23N3O10 |
| Molar mass | 393.3498 g/mol |
| Appearance | White crystalline solid |
| Melting point |
220°C (493.15 K, 428°F) |
| Boiling point |
decomposes at a higher temp. |
| Solubility in water | <0.5g/100ml |
| Hazards | |
| Flash point | Does not burn |
| Related compounds | |
| Related compounds | EDTA, NTA |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Diethylene triamine pentaacetic acid (DTPA) is an organic compound consisting of a diethylenetriamine backbone modified with five carboxymethyl groups. The molecule can be viewed as an elongated version of EDTA. DTPA is used as its conjugate base, often undefined, which has a high affinity for metal cations. Upon complexation to lanthanide and actinide ions, DTPA exists as the pentaanionic form, i.e. all five carboxylic acid groups are deprotonated.
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[edit] Uses
Since the 1960s, doctors have used DTPA as a chelating agent to treat internal contamination from radioactive materials such as americium, plutonium, californium, curium, and berkelium. Currently, DTPA is approved by the U.S. Food and Drug Administration (FDA) for chelation of only three radioactive materials: plutonium, americium, and curium. It is used as a soil extractant for available soil micronutrients like Zn,Fe,Cu and Mn at the pH of 7.3 with Calcium chloride and TEA. Furthermore, it is used as to chelate gadolinium to form a MRI contrast agent, such as Magnevist
[edit] Coordination chemistry
DTPA is the parent acid of an octadentate ligand, diethylene triamine pentaacetate. In some situations, all five acetate arms are not attached to the metal ion. It has been used to decontaminate humans who have been poisoned with plutonium, americium and other actinides. Upon formation of chelate complexes, these heavy metal ions are less readily unabsorb and are more readily eliminated in urine. It is normally used as the calcium or zinc salt. When given within the first day after internal contamination has occurred, Ca-DTPA is about 10 times more effective than Zn-DTPA at chelating plutonium, americium, and curium. After 24 hours have passed, Ca-DTPA and Zn-DTPA are equally effective in chelating these radioactive materials.[citation needed] "Internal contamination" is jargon for the unintention injestion of radioactive materials. Most cases of internal contamination result from working with radioactive materials.
[edit] Efficacy
DTPA cannot bind all of the radioactive materials that might get into a person’s body after a radiological or nuclear event, such as a terrorist attack with a “dirty bomb.” This medicine cannot prevent radioactive materials from entering the body. DTPA cannot reverse the health effects caused by radioactive materials once these materials have entered the body.
Chelating agents work best when given shortly after radioactive materials or poisons have entered the body. The more quickly a radioactive material or poison is removed from the body, the fewer and less serious the health effects will be. After 24 hours, plutonium, americium, and curium are harder to chelate. However, DTPA can still work to remove these radioactive materials from the body several days or even weeks after a person has been internally contaminated.
[edit] Safety
DTPA does not build up in the body or cause long-term health effects. People who are given repeat doses of Ca-DTPA within a short period of time may have nausea, vomiting, diarrhea, chills, fever, itching, and muscle cramps. Other side effects may include headache, lightheadedness, chest pain, and a metallic taste in the mouth.
Ca-DTPA (and Zn-DTPA) can chelate certain important minerals that the body needs (zinc, magnesium, and manganese). For example, the body needs zinc to make red blood cells, white blood cells, and platelets. Therefore, DTPA treatment may interfere with the normal production of blood cells. As a precaution, patients receiving long-term treatment with DTPA should be given a vitamin and mineral supplement that contains zinc.
[edit] References
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This article does not cite any references or sources. (November 2007) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed. |
- This article incorporates material from Facts about DTPA, a fact sheet produced by the United States Centers for Disease Control and Prevention.
