1,1'-[ethane-1,2-diylbis(thio)]bisbenzene

Endpoint summary

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:

no adverse effect observed (not irritating)

Additional information

In vitro skin Irritation

An in vitro test was to conducted to evaluate the skin irritation potential of the 1,1'-[ethane-1,2-diylbis(thio)]bisbenzene using EPISKIN^TM reconstructed human epidermis model. The study was conducted as per OECD test guideline 439 following good laboratory practices. The treatment period was for 15 minutes followed by a post-exposure incubation period of 42 hours. At the end of the post-exposure incubation period tissues were taken for MTT-loading. After MTT-loading a total biopsy of each epidermis was made for extraction of formazan crystals. At the end of the formazan extraction period the optical density was measured at 570 nm. The percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues) was calculated. The relative mean viability of the test item treated tissues was 105.7% after the 15-minute exposure period and 42 -hours post-exposure incubation period. The relative mean viability of negative control was 100% and for positive control was 6.8%.The test substance is not an skin irritant.

In vitro Skin Corrosion Test

An in vitro study was conducted to evaluate the corrosivity potential of the 1,1'-[ethane-1,2-diylbis(thio)]bisbenzene using test guideline OECD 431, EpiDerm™ Human Skin Model method.The corrosivity potential of 1,1'-[ethane-1,2-diylbis(thio)]bisbenzene was evaluated for treatment periods of 3 and 60 minutes. Duplicate tissues samples were treated with the test item for exposure periods of 3 and 60 minutes. Negative and positive control groups were treated for each exposure period. At the end of the exposure period the test item was rinsed from each tissue before each tissue was taken for MTT-loading. After MTT loading each tissue was placed in isopropanol for MTT extraction. At the end of the formazan extraction period the optical density (OD) was measured at 570 nm. Percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues) of test item for 3 minute exposure was 105.6% and after 60 minute was 104.5%. Positive control showed the viability of 3.9 and 4.8% in 3 and 60 minutes exposure. The test item is not corrosive to skin.

In vitro Eye irritation

Test was conducted to determine whether a test item, 1,1'-[ethane-1,2 diylbis(thio)]bisbenzene can induce serious eye damage and to identify test items requiring classification for eye irritation or serious eye damage. The study was conducted as per OECD test guideline 437 following good laboratory practices. The test item was applied neat for 240 minutes.  Negative and positive control items were tested concurrently.  The two endpoints, decreased light transmission through the cornea (opacity) and increased passage of sodium fluorescein dye through the cornea (permeability) were combined in an empirically derived formula to generate an In Vitro Irritancy Score. The IVIS scores for the test item, the negative control and the positive control were 0.4, 0.7, and 101.4, respectively. The test substance is not an eye irritant.

Justification for classification or non-classification

In vitro test for skin irritancy and corrosivity including human skin model assays (EPISKIN™ and EpiDerm™) were performed with test material 1,1'-[ethane-1,2 diylbis(thio)]bisbenzene. Based on the study results, the test item is not irritant to not corrosive to skin. The test substance is not classified for UN GHS or CLP regulations. Based upon numerical scores of BCOP (OECD 437) eye irritation method, the test material, 1,1'- [ethane-1,2 diylbis(thio)] bisbenzene is not classified for Eye Damage/ Eye Irritation according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and according to UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS).