Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

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

In this study the test item was assessed for its skin sensitising potential using the Local Lymph Node Assay (LLNA) in mice. Test item solutionat different concentrations was prepared in the vehicle DMF. For this purpose a local lymph node assay was performed using test item concentrations of 5, 10 and 25% (w/w). The highest concentration tested was the highest concentration that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation (as determined by two pre-experiments). The animals did neither show any signs of systemic toxicity nor local skin effects during the course of the study and no cases of mortality were observed. A statistically significant or biologically relevant increase in ear weights was not observed in any treated group in comparison to the vehicle control group. In this study Stimulation Indices (S.I.) of 2.14, 2.71 and 3.89 were determined with the test item at concentrations of 5, 10 and 25% (w/w) in DMF, respectively. A clear dose response was observed. A statistically significant and biologically relevant increase in DPM value and also in lymph node cell count was observed in all test item treated groups and a statistically significant and biologically relevant increase in lymph node weight was observed in the highest dose group in comparison to the vehicle control group. Furthermore, the cut-off value of 1.55 for a positive response regarding the lymph node cell count index reported for BALB/c mice was exceeded in all test item treated groups (indices of 1.6, 1.6 and 2.2, respectively). Thus, the test item was found to be a skin sensitizer and an EC3 value of 13.7% was derived.

After the second pre-test the animal treated with 10% test item concentration showed an erythema of the ear skin (score 1) between day 3 and 5. The animal treated with 25% test item concentration showed an erythema of the ear skin (score 1 or 2) between day 1 and 5. Furthermore, the increase in DMP ( appr. 2 fold) does not correlate with the increase in lymph node cell count (app. 4 fold). In an acute dermal irritations tudy the substance was found to be irritating to skin. In conclusion, there are hints that the skin irritation potential of the test item may have an influence on the outcome of the local lymph node assay. Therefore, a Bühler assay in guinea pig was proposed.

The aim of the Buehler test was to evaluate the possible allergenic activity of the test item after topical administration in guinea pigs. The induction phase was conducted with three topical applications of the test item to 20 guinea-pigs with occlusive dressing and a 13-day rest phase. The challenge phase, conducted under an occlusive dressing for 6 hours, consisted of a single topical application of the test item at 100% or an application of a negative control (liquid paraffin).

In the treatment group (treatment dose of 100%), a discrete erythema was noted in eleven animals (11/20) at the reading time 24 hours. No macroscopic cutaneous reactions attributable to allergy were observed 48 hours after the removal of the occlusive dressing. In the control group (associated with the treatment dose of 100%), a discrete erythema was noted in two animals (2/10) at the reading time 24 hours. No cutaneous intolerance reaction was observed 48 hours after the removal of the occlusive dressing. No cutaneous reaction was recorded in animals from the treated and control groups after the challenge phase, on the treated area with liquid paraffin (vehicle). As irritation was observed in the control group animals, only reactions in the test group animals that exceeded the most severe reactions seen in the control group animals were attributed to skin sensitization. Therefore, no sensitization reaction was noted in animals from the treated group 24 and 48 hours after the challenge phase, on the area challenged with the test item at 100%.

In view to confirm or infirm these results, a new challenge phase was performed with the test item diluted at 75% (w/w) in liquid paraffin and with liquid paraffin as control (vehicle), after a rest phase of 5 days. In the treatment group (treatment dose of 75%), a discrete to moderate erythema was noted in 20% (4/20), 5% (1/20) and 5% (1/20) at the reading time 24, 48, 72 hours, respectively. In the control group (associated with the treatment dose of 75%), a discrete erythema was noted in one animal (1/10) at the reading time 24 and 48 hours. No cutaneous intolerance reaction was observed 72 hours after the removal of the occlusive dressing. No cutaneous reaction was recorded in animals from the treated and control groups after the rechallenge phase, on the treated area with liquid paraffin (vehicle). As irritation was observed in the control group animals, only reactions in the test group animals that exceed the most severe reactions seen in the control group animals were attributed to skin sensitization. So, a sensitization reaction was noted in 10%, 5% and 5% of the animals from the treated group, 24, 48 and 72 hours after the challenge phase, on the area challenged with the test item at 75%. In conclusion, in view of these results, under these experimental conditions, the test item is not a skin sensitiser.


Migrated from Short description of key information:
The test item was assessed for its skin sensitising potential at concentrations of 5, 10 and 25% using the Local Lymph Node Assay (LLNA) in mice (OECD 429, GLP). The test material was found to be a skin sensitizer and an EC3 value of 13.7% was derived. There are hints that the skin irritation potential of the test item may have an influence on the outcome of the local lymph node assay. Therefore, a Bühler assay (OECD 406, GLP) in guinea pig was proposed. The Bühler assay was performed at concentrations of 100 % (induction and challenge) and 75% (re-challenge). Skin irritation was observed in control and test groups. The test item is not considered to be a skin sensitizer.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for skin sensitization under Directive 67/548/EEC.

                               

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for skin sensitization under Regulation (EC) No. 1272/2008.