N-carboxymethyliminobis(ethylenenitrilo)tetra(acetic acid)

Endpoint summary

Description of key information

Multiple skin and eye irritation studies using the DTPA acid and the pentasodium and potassium salts

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin Irritation:

The various studies available for DTPA acid, pentapotassium salt and pentasodium salt indicate that DTPA is not irritating to the skin.

Whilst DTPA acid, and the pentasodium and potassium salts would not be irritating to the skin, the residual sodium hydroxide present in some formulations of pentasodium DTPA can result in the solution being irritant or even corrosive, however this is due entirely to the presence of the sodium hydroxide.

Eye Irritation:

DTPA acid appears to be irritating in a minimally reported study. There was no assessment of the irritancy according to the Draize criteria, and the assessment of irritancy was therefore entirely qualitative. Studies performed using the sodium salt generally indicate a lack of irritancy to eyes whereas a study using the potassium salt showed slight eye irritation while a 40% solution of the potassium salt did not. These salts are placed on the market as solutions of approximately 40% chelating agent in water. Some of these solutions contain residual hydroxide left over by the manufacturing process. As with the skin irritation, this residual hydroxide can significantly increase the irritation potential. However if one considers the DTPA salts on their own, then the data indicate that there is a lack of eye irritation potential according to current guidelines with regard to the sodium salt and only slight irritation in case of the potassium salt. Considering that DTPA-H5 is an acid, and considering the reported reactions (extensive conjunctivitis, and moderate corneal damage) it is noted that this substance would likely be considered as an irritant to the eyes if a new guideline study were performed.

Respiratory irritation:

No data are available relating to respiratory irritation.

Effects on eye irritation: irritating

Justification for classification or non-classification

Skin irritation / corrosion: not irritating

Eye irritation: Category 2 (GHS)

DTPA-H5 does not meet the requirements for classification for skin irritation, but should be classified for eye irritation GHS Cat. 2 as described in the Guidance on the Application of the CLP criteria, Version 4.0 (2013).