2,5-xylenol

Endpoint summary

Description of key information

WoE QSAR predictions VEGA/CAESAR, result: 2,5-xylenol is predicted to be a skin sensitiser

WoE QSAR prediction QSAR Toolbox v4.1, result: 2,5-xylenol is predicted to be sensitising

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation, other

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

January 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

please refer to 'Attached justification'

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Guideline:

other: ECHA Guidanc R.6

Principles of method if other than guideline:

- Software tool(s) used including version: Vega v1.1.4
- Model(s) used: Skin sensitization model CAESAR v2.1.6
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Key result

Remarks on result:

positive indication of skin sensitisation based on QSAR/QSPR prediction

Prediction is Sensitizer. The result appears reliable due to calculated index values:

The predicted compound is into the Applicability Domain of the model (AD index = 0.931). Strongly similar compounds with known experimental value in the training set have been found (Similarity index = 0.867). Accuracy of prediction for similar molecules found in the training set is good (Accuracy index = 1). Similar molecules found in the training set have experimental values that agree with the predicted value (Concordance index = 1). Descriptors for this compound have values inside the descriptor range of the compounds of the training set (Descriptors range check = True). All atom centered fragment of the compound have been found in the compounds of the training set (ACF index = 1).

The prediction relies on 6 similar compounds (each with concordant experimental and predicted values) in the test and training data sets of the model: Creosol (CAS No 93-51 -6), anethole (CAS No 104-46-1), 1-naphthole (CAS No 90-15-3), 1-methoxy-4 -(2-propenyl)benzene (CAS No 140 -67-0), hydratropic acid (93-53-8), and benzaldehyde (CAS No 100 -52 -7).

Conclusions:

2,5-Xylenol is predicted by the CAESAR QSAR model for skin sensitization (v.2.1.6) to be a skin sensitiser. The result is considered to be reliable.

Executive summary:

2,5-Xylenol is predicted by the CAESAR QSAR model for skin sensitisation (v.2.1.6) to be a skin sensitiser. The model is implemented inside the VEGA platform and provides a qualitative prediction of skin sensitisation in the mouse Local Lymph Node Assay (LLNA).

The prediction relies on 6 similar compounds (each with concordant experimental and predicted values) in the test and training data sets: Creosol (CAS No 93-51 -6), anethole (CAS No 104-46-1), 1-naphthole (CAS No 90-15-3), 1-methoxy-4 -(2-propenyl)benzene (CAS No 140 -67-0), hydratropic acid (93-53-8), and benzaldehyde (CAS No 100 -52 -7).

The result appears reliable due to calculated index values: The predicted compound is into the Applicability Domain of the model (AD index = 0.931). Strongly similar compounds with known experimental value in the training set have been found (Similarity index = 0.867). Accuracy of prediction for similar molecules found in the training set is good (Accuracy index = 1). Similar molecules found in the training set have experimental values that agree with the predicted value (Concordance index = 1). Descriptors for this compound have values inside the descriptor range of the compounds of the training set (Descriptors range check = True). All atom centered fragment of the compound have been found in the compounds of the training set (ACF index = 1).

Reference 2

Endpoint:

skin sensitisation, other

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

2018-01-29

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

please refer to 'Attached justification'

Guideline:

other: ECHA Guidance R.6

Principles of method if other than guideline:

- Software tool(s) used including version: OECD QSAR Toolbox v4.1
- Model(s) used: Read-across (skin sensitisation)
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Key result

Remarks on result:

positive indication of skin sensitisation based on QSAR/QSPR prediction

Remarks:

OECD QSAR Toolbox v4.1

The substance is predicted to be sensitising by the OECD QSAR Toolbox v4.1. This prediction lies within the applicability domain of the model.

Conclusions:

2,5-xylenol is predicted to be sensitising. This prediction lies within the applicability domain of the model.

Executive summary:

Skin sensitisation of 2,5-xylenol was predited with the using the OECD QSAR Toolbox v4.1 (read-across approach), the substance is predicted to be sensitising. This prediction is based on data from LLNAs of three analogue substances: 2,3,6 -trimethylphenol (CAS 2416 -94 -6), 4 -tert-amylphenol (CAS 80 -46 -6) and Resorcin (CAS 108 -46 -3), which are concordantly positive. It lies within the applicability domain of the model.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Skin sensitisation:

The substance is classified according to Annex VI to Regulation (EC) No 1272/2008 as Skin Corr. 1B and therefore testing on skin sensitisation can be omitted. A QSAR approach is thus sufficient to cover the endpoint.

2,5-Xylenol is predicted by the CAESAR QSAR model for skin sensitisation (v.2.1.6) to be a skin sensitiser (Benfenati, 2018). The model is implemented inside the VEGA platform and provides a qualitative prediction of skin sensitisation in the mouse Local Lymph Node Assay (LLNA). The prediction relies on 6 similar compounds (each with concordant experimental and predicted values) in the test and training data sets: Creosol (CAS No 93-51 -6), anethole (CAS No 104-46-1), 1-naphthole (CAS No 90-15-3), 1-methoxy-4 -(2-propenyl)benzene (CAS No 140 -67-0), hydratropic acid (93-53-8), and benzaldehyde (CAS No 100 -52 -7). It lies within the applicability domain of this model.

The result obtained by the VEGA/CAESAR QSAR model appears reliable due to calculated index values: The predicted compound is into the Applicability Domain of the model (AD index = 0.931). Strongly similar compounds with known experimental value in the training set have been found (Similarity index = 0.867). Accuracy of prediction for similar molecules found in the training set is good (Accuracy index = 1). Similar molecules found in the training set have experimental values that agree with the predicted value (Concordance index = 1). Descriptors for this compound have values inside the descriptor range of the compounds of the training set (Descriptors range check = True). All atom centered fragment of the compound have been found in the compounds of the training set (ACF index = 1).

Also using the OECD QSAR Toolbox (read-across approach), the substance is predicted to be sensitising (Chemservice, 2018). This prediction is based on data from LLNAs of three analogue substances: 2,3,6 -trimethylphenol (CAS 2416 -94-6), 4 -tert-amylphenol (CAS 80-46-6) and Resorcin (CAS 108-46-3). It lies within the applicability domain of the model.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The substance is classified according to Annex VI to Regulation (EC) No 1272/2008 as Skin Corr. 1B and therefore testing on skin sensitisation can be omitted. Reliable predictions by the CAESAR QSAR model (v. 2.1.6), which is implemented in the VEGA platform, as well as the OECD QSAR Toolbox (v.4.1) showed a positive result. On the basis of the prediction, the substance is classified as skin sensitiser (Category 1, H317) according to Regulation (EC) No 1272/2008 (CLP Regulation).