4-[3-(4-chlorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]benzenesulphonamide

Endpoint summary

Description of key information

Not skin sensitising

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

No information on the skin sensitisation potential of the target substance is available. For this reason data on an analogue substance (similar substance 01) was taken into account. More details on the similarity between the two substances is reported in section 13.

human Cell Line Activation Test (h-CLAT)

The skin sensitization potential of “test item was studied following the method and testing procedures described into the OECD guideline 442E.

The extent of cytotoxicity induced on THP-1 cells by the test item was studied in two dose finding tests. The average test item concentration that results in 75 % cell viability compared to the solvent/vehicle control was 29.5 µg/ml.; the value was used for setting the dose-range for measuring CD86 and CD54 expression in the main test. Eight doses were used in three independent runs between 36 µg/mL – 10 µg/ml.

The increase in CD86 marker expression (RFI) was not equal to or greater than 150 % at any tested dose (with > 50 % of cell viability) compared to the respective negative controls in any of the independent runs. Therefore, all three runs were negative for CD86 marker expression.

The increase of CD54 marker expression (RFI) was greater than 200 % compared to the negative controls occasionally (with >50 % of cell viability) in the first independent runs. Nonetheless in the second and third runs no increase of CD54 expression was observed at any tested dose when the dose-levels were compared to the negative control. Based on the concordant results of the last two individual runs for CD54 expression, prediction was concluded as negative. Thus, the effective concentration was not determined for the test item.

Based on the results and the h-CLAT prediction model, the test item demonstrated a non-sensitizing potential in vitro under the experimental conditions of human Cell Line Activation Test.

KeratinoSens™ method

The skin sensitization potential of “test item was studied following the method and testing procedures described into the OECD guideline 442D (KeratinoSens™ method). In order to derive a prediction two independent tests for the test item and the positive control substance, respectively were conducted. Since the results of the two runs were concordantly negative, a third run was not needed to derive a conclusion. The luciferase activity induction obtained with the positive control, Trans-Cinnamaldehyde, was statistically significant above the threshold of 1.5-fold in all tests. For the test item, twelve doses ranging from 2000 μM to 0.98 μM were used in the first test and since strong cytotoxicity was observed a lower range from 15.625 μM to 0.181 μM was used in the second test. The test item induced cytotoxicity (viability below 70 %) in KeratinoSens™ cells compared to the solvent/vehicle. IC30 and IC50 values were determined as 4 μM and 7 μM respectively in the first run and the very same IC values were gained in the second run concordantly. Athough the test item exceeded the 1.5-fold threshold value for luciferase activity induction in the first test and an EC1.5 value was calculated as 27 μM, it occurred only at cytotoxic levels therefore the test was considered negative. In the second test the induction values of the test item did not exceed the 1.5-fold threshold, therefore EC1.5 values could not be determined. Moreover, no clear dose response could be observed in any of the tests.

Based on these results and the KeratinoSens™ prediction model, the test item Fluorescent Brightener 313 is concluded negative for skin sensitization potential under the experimental conditions of KeratinoSens™ method (ARE-Nrf2 Luciferase Test Method).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to the Guidance on the application of CLP criteria (ECHA, 2017): ''Validated in vitro/in chemico methods exist with the aim to identify a sensitising potential of a chemical. These include OECD TG442C (Peptide/protein binding), TG442D (keratinocyte response) and TG 442E (monocytic/dendritic cell response). The in vitro/in chemico tests are not regarded as stand alone tests and the result from such a test should be used together with other data in an overall assessment. Further, at present there is no agreed strategy on how to use in vitro/in chemico methods for direct estimation of sensitising potency, but data from such tests can be used together with other data in order to assess skin sensitisation potency. See also the Guidance on IR&CSA, especially Section R.7.3.4.1.''

Based on the results obtained in the two in vitro studies above described, the test substance was not classified as skin sensitizer .