Bis(4-chlorophenyl) sulphone

Endpoint summary

Description of key information

The substance 4,4'-dichlorodiphenyl sulfone (DCDPS) was slightly irritating to the skin of dermally exposed rabbits in the key study performed  similar to test guideline OECD 404. Although, desquamation was noted at the end of the 8-day obervation period.
In the key eye irritation study performed similar to test guideline OECD 405, DCDPS caused eye irritation.

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:

Unfortunately no skin irritation study is available which was performed according to the current OECD404 guideline or which is adequately reported. Therefore a precise classification in accordance to Directive 67/548/EEC and Regulation 1272/2008 is not possible.

For a worst case assessment a skin irritation study with significant deviations from the guideline needs to be selected as the key study (BASF AG, 1981). In this study 3 rabbits were dermally exposed to DCDPS (500 mg/application site; 80 % in water). A 24h exposure period was applied (guideline 4h) using an occlusive dressing (guideline semiocclusive). The test item was applied to the intact and scarified skin of each rabbit (2.5 x 2.5 cm per application site). The rabbits were only observed for 8 days post application (guideline 14 days). Scoring of the application sites was performed according to Draize at 24 and 72 hours and after 8 days (guideline 24, 48, 72h).

For the intact skin, very slight erythema (mean 0.8) and no oedema were observed at 24 and 72 hours. On day 8 after patch removal, desquamation to a very mild degree was noted at 2/3 application sites. Due to the absence of a clear irritation reaction no relevance for classification can be deduced. The use of scarified skin is not a standard method for testing dermal irritation and hence, the scores are reported in the robust study summary only.

These observations are supported by an insufficiently reported study no skin irritation was observed when six rabbits were exposed to 500 mg DCDPS for 24 h under occlusive conditions (, 1976). Observations were obviously only made till 48 h after removal of the test substance.

In a similarly incompletely reported assay no irritation was observed when an aqueous paste of DCDPS (2 g/kg) was applied to backs of three rats under occlusive dressings for 24 hours (ICI, 1970). The skin was washed and the compound re-applied 24 hours later. Six applications were made, but no signs of irritation were observed.

During the course of a Local Lymph Node Assay, no signs of local irritation were noted on the ears of treated mice (Harlan CCR, 2010).

 

Eye irritation:

As for skin irritation, no eye irritation study is available which was performed according to the current OECD405 guideline or which is adequately reported. Therefore a precise classification in accordance to Directive 67/548/EEC and Regulation 1272/2008 is not possible.

Again for a worst case assessment an eye irritation study with significant deviations from the guideline needs to be selected as the key study (BASF AG, 1981).

In this study 0.78 mg of grained DCDPS was instilled into the conjunctival sac of each one eye of 3 rabbits. No washing was performed after 24h (guideline: washing). Animals then were observed for 8 days (guideline 14 days) and effects scored by the method of Draize at 24, 48 and 72 hours and on day 8. In all tested animals, the mean cornea score and the mean iris score were each 1, while the mean conjunctivae score and the mean chemosis score were each 2. At the end of the observation period, chemosis and iris effects had resolved. Cornea and conjunctivae effects were not fully reversible, but showed a clear tendency towards reversibility. Furthermore slight scar formation was noted in all test animals at the 48-hour and subsequent readings. Based on the effects observed a clear discrimination between primary irritating and/or secondary irritation based on mechanical distress caused by the solid, nearly unsoluble test sustance in the unwashed eyes is not possible. Furthermore only a very short observation period (8 days) was performed to address the reversibility.

The slight scar formation at the end of the observation period can therefore not be considered as relevant for classification.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: irritating

Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

Based on the Draize scores identified on the intact shaved skin no relevant irritation responses were observed. Therefore no classification for skin irritation is warranted according to Directive 67/548/EEC and Regulation 1272/2008.

With regard to the key eye irritation study, DCDPS is subject to classification with R36 (irritating to eyes) according to Directive 67/548/EEC and Category 2 (H319: Causes serious eye irritation) according to Regulation 1272/2008/EC. Due to the absent rinsing of the solid test substance and the short observation period of only 8 days, the reversibility of the observed effects could not be unequivocally evaluated.