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Description of key information

BAL0001022, tested in DMF, did not show any sensitisation potential (non-sensitizer) in the Local Lymph Node Assay.

Key value for chemical safety assessment

Skin sensitisation

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

The aim of this study was to determine the skin sensitisation potential of BAL0001022 following dermal exposure in mice. The study was being performed with vertebrate animals as the applied regulatory in vitro alternative tests showed inconclusive/equivocal results. Therefore, an in vivo study was being run to provide reliable information about the skin sensitisation potential of the test item for regulatory acceptance.

The solubility of the test item was examined in a short Preliminary Compatibility Test. The following standard OECD vehicles were assessed: Acetone: Olive oil 4:1 (v/v) mixture, N,N-dimethylformamide (abbreviated as DMF). The best vehicle taking into account the test item characteristics, its usage and the requirements of the relevant OECD guideline was considered to be DMF. The 100% (w/v, i.e. 1 g per mL with added vehicle) dilution was the highest concentration suitable for the test. The 100% (w/v) formulation appeared, by visual examination, to be solution by visual examination.

 

A Preliminary Irritation/Toxicity Test was performed in CBA/CaOlaHsd mice using two doses (2 animals/dose): 100 and 50 % (w/v) in DMF and based on the results, 100 % (w/v) was selected as top dose for the main test.

In the main assay, twenty female CBA/CaOlaHsd mice were allocated to five groups, each groups comprised four animals.

-groups (three) of animals received BAL0001022 (formulated in DMF) at either 100, 50 or 25 % (w/v),

-a negative control group received the vehicle (DMF) only,

-a positive control group received 25 % (w/v) HCA (dissolved in DMF).

 

The test item solutions were applied to the dorsal surface of the ears of the experimental animals (25 µL/ear) for three consecutive days (Days 1, 2 and 3) and then maintained on study for an additional 3 days. Cell proliferation in the (local) lymph nodes was assessed by measuring disintegrations per minutes after the incorporation of tritiated methyl thymidine (3HTdR) into the lymph nodes and the values obtained were used to calculate stimulation indices (SI) in comparison with the control group.

 

There was no mortality or signs of systemic toxicity observed during the study. Alopecia around the ears was present in the 100 % (w/v) group from Day 3 (2 out of 4 animals) or Day 4 (2 out of 4 animals), and in the 50 % (w/v) group from Day 3 (4 out of 4 animals).

Test item precipitate / minimal amount of test item precipitate was observed on the ears of all test item treated animals during the study.

No marked group mean body weight losses (≥5%) were observed in any groups.

The SI values were 1.2, 1.2 and 1.4 at concentrations of 100, 50 and 25 % (w/v), respectively.

The SI value for the positive control substance a-Hexylcinnamaldehyde (HCA) dissolved in the same vehicle was 9.9 therefore demonstrating the appropriate performance of the assay. The lymphoproliferative response of the HCA was in line with historical control data was for the positive control chemical therefore confirming the validity of the assay.

 

In conclusion, under the conditions of the present assay, BAL0001022, tested in DMF, did not show any sensitisation potential (non-sensitizer) in the Local Lymph Node Assay.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

BAL0001022, tested in DMF, did not show any sensitisation potential (non-sensitizer) in the Local Lymph Node Assay. 

No classification/labelling is triggered according to Regulation (EC) No 1272/2008 (CLP) / GHS (rev. 7) 2017.