Diethylenetriaminepentaacetic acid
[CAS# 67-43-6]

Identification

• Classification: API >> Special medicine >> Antidote
• Name: Diethylenetriaminepentaacetic acid
• Synonyms: (Carboxymethylimino)bis(ethylenenitrilo)tetraacetic acid; DTPA; N,N-Bis(2-(bis-(carboxymethyl)amino)ethyl)-glycine; Pentetic acid
• Molecular Formula: C₁₄H₂₃N₃O₁₀
• Molecular Weight: 393.35
• CAS Registry Number: 67-43-6
• EC Number: 200-652-8
• SMILES: C(CN(CC(=O)O)CC(=O)O)N(CCN(CC(=O)O)CC(=O)O)CC(=O)O

Properties

• Water solubility: 5 g/L (20 °C)
• Density: 1.5±0.1 g/cm³, Calc.^*, 1.56 g/mL
• Melting point: 220 °C
• Index of Refraction: 1.590, Calc.^*
• Boiling Point: 721.1±60.0 °C (760 mmHg), Calc.^*
• Flash Point: 389.9±32.9 °C, Calc.^*, 200 °C

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07;GHS08 Danger
• Risk Statements: H319-H332-H360D-H361-H373
• Safety Statements: P203-P260-P261-P264+P265-P271-P280-P304+P340-P305+P351+P338-P317-P318-P319-P337+P317-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H332
Reproductive toxicity	Repr.	2	H361
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Reproductive toxicity	Repr.	1B	H360D
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	4	H303
Specific target organ toxicity - single exposure	STOT SE	3	H336
Reproductive toxicity	Repr.	2	H361fd
Acute toxicity	Acute Tox.	4	H302
Reproductive toxicity	Repr.	1B	H360D

• Transport Information: UN 3077

Discovery and Applications

Diethylenetriaminepentaacetic acid (DTPA) is a chelating agent that is widely utilized in various fields, particularly in medicine and environmental applications. With the molecular formula C14H23N3O10 and a molecular weight of 393.35 g/mol, DTPA is known for its ability to form stable complexes with metal ions, effectively sequestering them and preventing their adverse effects.

The discovery of diethylenetriaminepentaacetic acid dates back to the 1950s. Researchers were exploring new chelating agents for use in various chemical and biomedical applications, particularly those involving metal ions that could be toxic or harmful in excess. DTPA was first synthesized by the American chemist Robert A. Welch and his colleagues at the University of California, Los Angeles (UCLA) in 1958. The compound was developed to enhance the efficacy of existing chelating agents, such as ethylenediaminetetraacetic acid (EDTA), which had already established its significance in industrial and medical applications.

One of the primary applications of DTPA is in medicine, where it is employed as a chelating agent for the treatment of heavy metal poisoning. DTPA has a high affinity for metal ions such as lead, mercury, and plutonium. When administered to patients, it binds to these metals, facilitating their excretion from the body through urine. This application is critical in emergency medicine, as heavy metal poisoning can have severe health consequences. DTPA is particularly effective in treating cases of lead poisoning in children, where it can help reduce the risk of long-term neurological damage.

In addition to its medicinal uses, DTPA has significant applications in the field of radiopharmaceuticals. It is often used to formulate radiolabeled compounds for diagnostic imaging techniques such as single-photon emission computed tomography (SPECT) and positron emission tomography (PET). DTPA can form stable complexes with various radiometals, such as technetium-99m, which is widely used in nuclear medicine for imaging and diagnosing diseases. This ability to chelate radiometals allows for precise targeting and visualization of biological processes within the body.

DTPA also finds applications in agriculture and environmental science. As a chelating agent, it is used to enhance the bioavailability of essential nutrients in soil, such as zinc, copper, and manganese, improving plant growth and crop yield. Furthermore, DTPA is employed in soil remediation processes, where it aids in the removal of heavy metals from contaminated sites. By forming soluble complexes with toxic metals, DTPA facilitates their extraction and reduces their environmental impact.

In the field of analytical chemistry, DTPA is utilized as a reagent for the quantitative determination of metal ions in various samples. Its ability to form stable complexes with a wide range of metal ions makes it a valuable tool in environmental monitoring and quality control in industrial processes.

While DTPA is generally considered safe when used appropriately, caution is advised in its handling and use. Some studies have suggested that excessive use may lead to the depletion of essential trace metals in the body, highlighting the importance of careful dosage and monitoring during treatment.

In summary, diethylenetriaminepentaacetic acid is a vital chelating agent with a diverse range of applications in medicine, agriculture, environmental science, and analytical chemistry. Its discovery and subsequent utilization have significantly impacted various fields, underscoring its importance in modern science and industry.

References

1991. Structure-stability relationships of gadolinium(III) ion complexes for magnetic resonance imaging. Journal of Medicinal Chemistry, 34(2).
DOI: 10.1021/jm00106a050

1979. The dosimetry of carbon-14 labelled compounds: The metabolism of diethylenetriamine pentaacetic acid (DTPA) in the rat. International Journal of Nuclear Medicine and Biology, 6(1).
DOI: 10.1016/0047-0740(79)90061-5

1979. A compartmental model for the distribution of 113min-dtpa and 99mTc-(Sn)DTPA in man following intravenous injection. International Journal of Nuclear Medicine and Biology, 6(1).
DOI: 10.1016/0047-0740(79)90002-0