Methyl phenyl sulphide

Endpoint summary

Description of key information

Three in vitro irritation/corrosion studies are available to determine the potential irritancy of the test substance.  The EPISKIN Standard Model was used for the skin irritation study and the skin corrosion model and the Bovine Corneal Opacity and Permeability Test was used for the eye irritation study.  All studies were conducted according to the relevant guidelines.
Neither of the assays for corrosive effects gave positive results but the in vitro result for skin irritation did indicate the material should be classified asa  potential skin irritant.  Ocular irritation was assessed by read across to a QSAR analysis completed for phenyl sulphide.  On this basis thioanisole is classified as a  moderate eye irritant

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin Irritation/Corrosion:

In a study conducted by Verbaan (2010), the test substance, Thioanisole, was investigated for its potential to cause irritation when tested using an in vitro human skin model, a three dimensional epidermal model (EPISKIN Standard Model). 10ul of Thioanisole was applied undiluted directly on top of the skin tissue for an exposure period of 15 minutes. After a 42 hour incubation period, determination of sytotoxic effect was determined. Skin irritancy was expressed as the remaining cell viability after exposure to the test substance. The relative mean tissue viability obtained after 15 minutes treatment with Thioanisole compared to the negative control tissues was 11%. As the mean relative tissue viability for Thioanisole was below 50% after 15 minutes treatment, it was considered to be an irritant under the experimental conditions of this test. Based on this result, the test substance should be classified as a Category 2 irritant in accordance with Regulation EC No. 1272/2008 and should have the signal word Warning and the Hazard statement H315: Causes skin irritation associated with it. According to Directive 67/548/EEC, the test substance should be classified as an Irritant (Xi) and have the risk phrase R38: Irritating to skin associated with it.

A study by Buskens, C.A.F., 2010, details an in vitro skin corrosion test with Thioanisole which was performed using a human skin model. The possible corrosive potential of Thioanisole was tested through topical application for 3 minutes and 1 hour. The study was carried out in accordance with OECD and EC Guidelines. Thioanisole was applied undiluted (50 uL) directly on top of the skin tissue.

Skin corrosion is expressed as the remaining cell viability after exposure to the test substance. The relative mean tissue viability obtained after 3 -minute and 1 -hour treatments with Thioanisole compared to the negative control tissues was 109 % and 59 %, respectively. Because the mean relative tissue viability for Thioanisole was not below 50 % after the 3 -minute treatment and not below 15 % after the 1 -hour treatment Thioansiole is considered to be not corrosive. Based on these results, Thioanisole does not require classification according to Regulation EC No. 1272/2008 or Directive 67/548/EEC.

The key study was determined to be the study conducted by Verbaan (2010). The principle reason for this is that, while a corrosive study is available, as the test substance is classified as not corrosive according to the results of this study, the skin irritation study, conducted by Verbaan (2010), was necessary in order to determine the potential irritancy of the substance.

Eye Irritation/Corrosion:

In a study conducted by Verspeek-Rip (2010), a screening test examining the eye irritancy potential of Thioanisole was conducted using the Bovine Corneal Opacity and Permeability test (BCOP test). The possible ocular irritancy of Thioanisole was tested through topical application for 10±1minutes. The test substance was applied undiluted at a concentration of 750 µl directly on top of the corneas. Following treatment with the test substance, Thioanisole did not induce ocular irritation, with a mean in vitro irritancy score of 3.9 after 10 minutes of treatment. Based on these results, the test substance was not considered to be a severe irritant or corrosive.

QSAR analysis designed to evaluate eye irritation using 36 descriptors to describe test molecules, leading to a three class distinction of irritants where reactions would be expected to resolve within 24 hours, moderate to severe irritants where effects resolve within 21 days and severe irriants where effercts are not expected to resolve within 21 days. In the QSAR analysis fragments, substructural and topological descriptors were applied to the test molecules.

Phenyl sulphide is predicted by QSAR analysis to be a moderate to severe irritant. By read across thioanisole, methyl phenyl sulphide, is also anticipated to elicit ocular reactions leading to classification as a moderate eye irritant. This response would be consistent with indications from in vitro skin irritation testing that also classifies methyl phenyl sulphide as irritant.

Based on this read across information Thioanisole is classifed according to DPD and GHS systems as a moderate eye irritant with the appropriate risk and safety phrases.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: moderately irritating

Justification for classification or non-classification

Skin Irritation/Corrosion:

Based on the results of the key study, the test substance, Thioanisole, should be considered to be a Category 2 irritant in accordance with Regulation EC No. 1272/2008 and should have the signal word Warning and the Hazard statement

H315: Causes skin irritation associated with it. According to Directive 67/548/EEC, the test substance should be classified as an Irritant (Xi) and have the risk phrase R38: Irritating to skin associated with it.

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Eye Irritation/Corrosion:

Based on the results of the key study and weight of evidence from read across to phenyl sulphide and comparison with skin irritation data, Thioanisole should be considered to be a Category 2 irritant in accordance with Regulation EC No. 1272/2008 and should have the signal word Warning and the Hazard statement

H319: Causes serious eye irritation associated with it. According to Directive 67/548/EEC, the test substance should be classified as an Irritant (Xi) and have the risk phrase R36: Irritating to eyes associated with it