Registration Dossier

Administrative data

Description of key information

Several in vivo tests with a 40-50% solution of tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate ("PBTCNa4") in rabbits are available. The test solution was applied on the inner surface on rabbit ears. In these tests PBTCNa4 was not irritating. 
In a further test the test item was classified as irritant, based on the content of phosphonic acids > 10%.
Aditionally for the evaluation of the skin corrosion/irritating properties of PBTCNa4 an artificial 3D-skin model test according to OECD TG 431/439 was used.
Two in vivo assay in rabbits equivalent or similar to OECD TG 405 are available. In these assays a 40-50% solution of PBTCNa4 in water was used. Additionally an in vitro study for assessing ocular irritation of compounds using a human epithelial corneal cell model was conducted.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation
Remarks:
other: artificial human 3D-Cornea model
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study
Principles of method if other than guideline:
In vitro study for assessing ocular irritation of compounds using a human epithelial corneal cell model. The model used is standardized and commercially available (SkinEthic™ Human Corneal Epithelial Model (HCE); SkinEthic, France).
GLP compliance:
yes
Species:
other: not applicable - human corneal epithelial model (HCE)
Strain:
other: not applicable - human corneal epithelial model (HCE)
Vehicle:
other: not applicable - human corneal epithelial model (HCE)
Controls:
other: not applicable - human corneal epithelial model (HCE)
Duration of treatment / exposure:
After an exposure period of 60 minutes, followed by a 16 hours post-treatment incubation period, the cell viability was measured
Observation period (in vivo):
not applicable - human corneal epithelial model (HCE)
Number of animals or in vitro replicates:
not applicable - human corneal epithelial model (HCE)
Irritation parameter:
other: cell viability
Basis:
mean
Time point:
other: 60 minutes followed by a 16 h post-treatment period
Score:
84.62
Max. score:
100
Reversibility:
other: not applicable - human corneal epithelial model (HCE)
Remarks on result:
other: non-irritant - scores in [%] viability

A test substance is predicted to be an ocular irritant if the mean relative tissue viability (%) exposed to the test substance is <50%.

As can be seen from the information in the Table below the test substance tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate was not detected as positive in this test model.

Compound                     Cell viability [%]       Evaluation

Test item                          101.56                 non-irritant

Positive control                    1.50                     irritant

Negative control               100.00               non-irritant

Interpretation of results:
not irritating
Remarks:
Migrated information
Executive summary:

This in vitro study for assessing ocular irritation of compounds using a human epithelial corneal cell model was performed in 2012. The model used is standardized and commercially available (SkinEthicTM Human Corneal Epithelial Model (HCE); SkinEthic, France).

Undiluted tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate was applied topically to the HCE tissue, i.e. 30 mg per insert (plus 30 µl PBS to moisten and ensure good contact with the skin; three replicates).

After an exposure period of 60 minutes, followed by a 16 hours post-treatment incubation period, the cell viability was 85% (rounded) as measured by a MTT conversion assay.

The results of the concurrent negative (NC, PBS) and positive control (PC, 1H-1,2,4-Triazole-3-thiol) demonstrated the viability (NC) and sensitivity (PC) of the test model.

The results show that tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate is predicted as non-irritant under the conditions of this test method.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

In the in-vivo assays tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate was not irritating to the eyes and skin of rabbits. This also applies for the in-vitro assays.

For the in vivo tests an aqueous solution was used. Therefore the tests are regarded as supporting studies and in-vitro tests with the water free test substance were conducted.


Justification for selection of skin irritation / corrosion endpoint:
For the evaluation of the skin corrosion/irritating properties of tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate an artificial 3D-skin model was used. Both studies are used for classification to differentiate if the substance is corrosive or irritant.
Additionally the results of in-vivo studies (40-50% solution of the test substance ) were taken into account.

Justification for selection of eye irritation endpoint:
For the evaluation of the eye irritant properties of tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate a test using a human epithelial corneal cell model was used.
Additionally the results of in-vivo studies (40-50% solution of the test substance ) were taken into account.

Justification for classification or non-classification

Tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate was not irritating to the skin and eyes in the in vivo and not irritating/corrosive in the in vitro assays. Therefore a classification is not justified.