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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

There are two skin maximisation tests available that evaluate the contact allergenic potency of sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate. The study with the higher dose level at the challenge treatment (25 % test article in physiological saline) was used as key study.

Maximization test (Key study):

This test was based on the OECD Guideline No. 406 (Skin Sensitisation) and the EU method B.6 (Skin Sensitisation). The intradermal induction of sensitization was performed with a 5 % dilution of the test article in physiological saline and in an emulsion of Freund's Complete Adjuvant (FCA)/ physiological saline. The epidermal induction of sensitization was conducted under occlusion with the test article at 25 % in physiological saline. Two weeks after the epidermal induction application the challenge was completed by epidermal application of the test article at 25 % in physiological saline under occlusive dressing. A second challenge was performed two weeks after the first challenge with concentration of 25 %. The method was equal to that described for the first challenge with the exception that the flanks of all the guinea-pigs were changed. The animals of the control group were induced with FCA/physiological saline and challenged similarly to those of the test group. Cutaneous reactions, i.e. erythema and oedema formation were evaluated at 24 and 48 hours after removal of the dressing. At the vehicle control no positive reactions were evident after the first and second challenge application. Positive reactions (edema, erythema, necroses) were observed after first challenge in 3 respectively 2 animals after 24- and 48 -hours reading. At the second challenge positive reactions were observed in 2 respectively 1 animal(s) after the 24- and 48 -hours reading. The test substance is, therefore, considered not to be a sensitizer when used under the described test conditions.

Maximization test (Supporting study):

This test was based on the OECD Guideline No. 406 (Skin Sensitisation) and the EU method B.6 (Skin Sensitisation). The intradermal induction of sensitization was performed with a 5 % dilution of the test article in bi-distilled water and in an emulsion of Freund's Complete Adjuvant (FCA)/ physiological saline. The epidermal induction of sensitization was conducted under occlusion with the test article at 50 % in bi-distilled water. Two weeks after the epidermal induction application the challenge was completed by epidermal application of the test article at 10 % in bi-distilled water under occlusive dressing. The animals of the control group were induced with bi-distilled water and FCA/physiological saline and challenged similarly to those of the test group. Cutaneous reactions, i.e. erythema and oedema formation were evaluated at 24 and 48 hours after removal of the dressing. None of the animals of the control and test group were observed with skin reactions after challenge treatment with a non-irritant test article concentration of 10 % in bidistilled water. Therefore, the test article applied at a concentration of 10 % in bi-distilled water is considered not to be a sensitizer when used under the described test conditions.

LLNA (Key study):

In addition, a local lymph node skin sensitisation test with the test substance sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate in mice was performed according to OECD Guideline 429. The assay determines the level of T lymphocyte proliferation in the lymph nodes draining the site of chemical application, by measuring the amount of radiolabelled thymidine incorporated into the dividing cells. The test substance was applied as 3%, 10% or 30% w/v preparations in propylene glycol. The application of the test substance at concentrations of 3%, 10% and 30% w/v in propylene glycol resulted in an isotope incorporation which was less than 3-fold at all three concentrations. Consequently, the test substance is not considered to be a potential skin sensitizer. In a positive control study, hexylcinnamaldehyde was shown to have the capacity to cause skin sensitisation when applied as 1%, 3% or 10% w/v preparations in acetone, confirming the validity of the protocol used for this study.

Photoallerginicity test (Supporting study)

In order to assess the photoallergenic potential of sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate a photoallergenicity test according to the CTFA Safety Testing Guidelines was carried out in 30 female (20 test and 10 control) Albino Dunkin Hartley guinea pigs. For the induction of sensitization 30 % of the test article in bi-distilled water was applied epicutaneously to a skin area of 8 cm2 (marked previously with 4 intradermal injections of Freund's Complete Adjuvant (FCA)/physiological saline). The test sites were then exposed to 1.8 J/cm2 UV-B and 10 J/cm2 UV-A irradiation. This procedure was repeated 4 times within 2 weeks of the induction phase. Control animals were intradermally treated with FCA/physiological saline only. Three weeks after beginning of the induction a challenge was carried out by treating the experimental animals (test and control) epicutaneously on both flanks with the test article at the concentrations of 15 %, 10 %, 5 % and 1 % (dilutions in bidistilled water). Treated sites were then either exposed to 10 J/cm2 UV-A irradiation (left flank) or remained unirradiated (right flank). Cutaneous reactions, i.e. erythema and oedema formation were evaluated at 24, 48 and 72 hours after the challenge exposure. No toxic symptoms were evident in the guinea pigs of the control or test group. It can be concluded that the test does not exhibit photollergenic potential in the guinea pig under the study conditions.


Migrated from Short description of key information:
Two maximisation tests in guinea pigs were performed to determine the contact allergenic potency of the test article. These tests were based on the OECD Guideline No. 406 (Skin Sensitisation) and the EU method B.5 (Skin Sensitisation). In the first test none of the control and test group animals were observed with skin reactions after challenge treatment with a non-irritant test article concentration of 10 % in bi-distilled water. In the other test 10% and 5% of the animals of the test group (25 % test article in physiological saline) showed skin reactions 24 and 48 hours after removing the dressings, respectively. The test substance is, therefore, considered not to be a sensitizer when used under the given test conditions.

Additionally, a Local Lymph Node Assay (LLNA) was performed according to the OECD Guideline 429. Also in this study the test substance is not considered to be a potential skin sensitizer.

One photosensitisation test (photoallergenicity) was performed according to the CTFA Safety Testing Guidelines. In this study the test substance did not exhibit a photoallergenic or phototoxic potential in the guinea pig under the given study conditions.

Justification for classification or non-classification

In the evaluation of all available information, the test substance is not classified with regard to sensitisation according to Directive 67/548/EEC (DSD) and to Regulation (EC) No 1272/2008 (CLP), respectively.

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