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Administrative data

Description of key information

No experimental data were available concerning the skin sensitisation potential of isobutanol. To assess to sensitising potential of isobutanol, information are available taken from a QSAR calculation and from experimental data of the analogous substance Propan-1-ol (CAS No. 71-23-8).

QSAR
OASIS TIMES MIX V2.25.3: not sensitizing (BASF SE 2008)

Propan-1-ol
guinea pig, GMPT: negative (OECD 406, Gad et al. 1986)

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation, other
Remarks:
other: Calculation
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
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:
1. SOFTWARE: OASIS TIMES v2.27.19.13

2. MODEL (incl. version number): v.21.26

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL: CAS No.: 78-83-1, Smiles Code: CC(C)CO

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: skin sensitization
- Unambiguous algorithm: skin sensitization with autoxidation
- Defined domain of applicability: Isobutanol is in the applicability domain of the model
- Appropriate measures of goodness-of-fit and robustness and predictivity: For substances in the applicability domain, a predictivity of 100 % was found for 100 industrial chemicals for the distinction of non-sensitizers of GHS Category 1.
- Mechanistic interpretation: Model predictions are based on simulation of skin metabolism and covalent interactions with proteins.

5. APPLICABILITY DOMAIN
- Descriptor domain: The chemical fulfills the general properties requirements and is in the interpolation structural space.
- Structural and mechanistic domains: N/A
- Similarity with analogues in the training set: not reported

6. ADEQUACY OF THE RESULT
The substance falls within the applicability domain of the model and the predictivity of the model for substance within its applicability domain was found to be reliable. Therefore, the preditction of isobutanol as a non-sensitizer is considered acceptable for the purposes of EC 1907/2006 and classification and labelling according to GHS criteria.

For further information see attached files for justification (QMRF & QPRF)
Principles of method if other than guideline:
A quantitative structure-activity relationship (QSAR) system for the estimation of the skin sensitization potency that incorporates skin metabolism and consideres the potential of parent chemicals and/or their activated metabolites to react with skin proteins. A chemically divers training set was used and their skin sensitization potency assigned to one of three classes.
Key result
Parameter:
EC3
Remarks on result:
no indication of skin sensitisation based on QSAR/QSPR prediction

The QSAR program calculated a negative sensitization potential of the test substance.

OASIS Times Mix V.2.25.8 assessed 2 -methylpropan-1 -ol and one metabolite as non sensitiser.

Interpretation of results:
GHS criteria not met
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

No experimental data were available concerning the skin sensitisation potential of isobutanol. To assess to sensitising potential of isobutanol, information are available taken from a QSAR calculation and from experimental data of the analogous substance Propan-1-ol (CAS No. 71-23-8).

 

QSAR

The potential of butan-1 -ol for skin sensitising was calculated using the software OASIS TIMES MIX V2.25.3 (BASF SE 2008). The program predicted the parent substance and one metabolite as no sensitiser.

 

Propan-1 -ol

A guideline conform (OECD 406, guinea pig maximisation test) study was performed with 15 Hartley guinea pigs in the test group (Gad et al. 1986). Induction was performed via intradermal and occlusive epicutaneous application of the undiluted propan-1-ol; the challenge with the undiluted substance was administered occlusive epicutaneously. None of the animals showed signs of skin sensitisation.

 

Therefore, there is currently no indication for a sensitizing potential of isobutanol.

 

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Read-across justification

Regarding relevant physical-chemical properties (i.e. water solubility, lipophilicity), propan-1-ol possesses comparable characteristics as isobutanol. Additionally, according to their chemical structure both substances vary only in one -CH2 group and owns the same (alcoholic) functional group. The available data for propan-1-ol is therefore suitable for read-across to isobutanol.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Due to the negative results of a QSAR calculation for isobutanol and of the analogous substance propan-1-ol in a guinea pig maximisation test, isobutanol has not to be classified as skin sensitiser according to 1272/2008/EC (CLP) requirements.