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EC number: 205-305-4 | CAS number: 137-66-6
Results of pre-tests: To determine the highest non-irritant test concentration that at the same time did not induce signs of systemic toxicity, a pre-test was performed in two animals. Two mice were treated by (epidermal) topical application to the dorsal surface of each ear with test item concentrations of 10 and 25% once daily each on three consecutive days. Prior to the first application of the test item and before sacrifice the body weight was determined. Clinical signs were recorded at least once daily. Eventual signs of local irritation were documented and a score was used to grade a possible erythema of the ear skin. Furthermore, prior to the first application of the test item (day 1), on day 3 and before sacrifice (day 6) the ear thickness was determined using a micrometer. Additionally, for both animals, the ears were punched after sacrifice (day 6) at the apical area using a biopsy punch (Ø 8 mm corresponding to 0.5 cm2) and were immediately pooled per animal and weighed using an analytical balance. Eventual ear irritation was considered to be excessive if an erythema of the ear skin of a score value ≥3 was observed at any observation time and/or if an increase in ear thickness of ≥25% was recorded on day 3 or day 6.
At the tested concentrations the animals did not show any signs of systemic toxicity. From day 1 to 6, the animals showed an erythema of the ear skin (day 1 to 5: Score 1, day 6 Score 4 (=eschar formation, detected during preparation)).
Therefore, a second pre-test was performed using test item concentrations of 2.5 and 5%. From day 1 to 6, the animals showed an erythema of the ear skin (Score 1 to 2). On day 6, upon preparation, both animals showed slight eschar formation.
Therefore, a third pre-test was performed using test item concentrations of 0.5 and 1%. From day 2 to 5, the animals showed an erythema of the ear skin (Score 1 to 2). On day 6 the animal treated with 1% of the test substance showed slight eschar
In the study the test item Ascorbyl Palmitate formulated in DMF (dimethylformamide) was assessed for its possible skin sensitising potential.
For this purpose a local lymph node assay was performed using test item concentrations of 0.1, 0.25, and 0.5% (w/w). The highest concentration tested was the highest concentration that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation as confirmed by three pre-experiments. The animals did not show any signs of systemic toxicity during the course of the study and no cases of mortality were observed. From days 2 to 4, the animals treated with a test item
concentration of 0.25 and 0.5% showed an erythema of the ear skin (Score 1). Animals treated with 0.1% test item concentration did not show any signs of local skin irritation. A relevant increase in ear weights was not observed.
In this study Stimulation Indices (S.I.) of 0.9, 0.9, and 1.1 were determined with the test item at concentrations of 0.1, 0.25, and 0.5% (w/w) in DMF, respectively.
The test item Ascorbyl Palmitate was not a skin sensitiser under the test conditions of this study.
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