1,2,3,4,4a,5,6,7-octahydro-2,5,5-trimethyl-2-naphthol

Endpoint summary

Description of key information

Skin corrosion: Not corrosive based on an OECD TG 431 test.

Skin irritation: Irritating based on an OECD TG 439 test.

Eye irritation: Severely irritating based on an OECD TG 438 test.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Additional information

Skin corrosion

The corrosive potential of the test item was tested through topical application for 3 minutes and 1 hour. The study procedures described in this report were according to OECD TG 431 and GLP principles. The test item (a liquid) was applied undiluted (50 μL) directly on top of the skin tissue. The positive control had a mean relative tissue viability of 7.2% after the 1-hour exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the acceptance limits of OECD TG 431 (lower acceptance limit ≥0.8 and upper acceptance limit ≤2.8) and the laboratory historical control data range. In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was ≤ 14%, except for the 1-hour test item treated tissues, which showed a Coefficient of Variation of 36%. However, since both individual values were in the same category, this minor deviation did not affect the study integrity indicating that the test system functioned properly. The relative mean tissue viability obtained after 3-minute and 1-hour treatments with the test item compared to the negative control tissues was 100% and 47%, respectively. Because the mean relative tissue viability for the test item was not below 50% after the 3-minute treatment and not below 15% after the 1-hour treatment the test item is considered to be not corrosive. In conclusion, the test item is not corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.

 

Skin irritation

The possible skin irritation potential of the test item was tested through topical application for 15 minutes on a human three dimensional epidermal model (EPISKIN Small model (EPISKINSM)). The study procedures described in this report were based on the most recent OECD TG 439 and GLP principles. The test item was applied undiluted (25 μL), directly on top of the skin tissue for 15 ± 0.5 minutes. After a 42 hour post-incubation period, determination of the cytotoxic (irritancy) effect was performed. Skin irritation is expressed as the remaining cell viability after exposure to the test item. The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with the test item compared to the negative control tissues was 12%. Since the mean relative tissue viability for the test item was below 50% after 15 ± 0.5 minutes treatment it is considered to be irritant. The positive control had a mean cell viability of 24% after 15 ± 0.5 minutes exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was ≤ 29%. The high standard deviation is caused by one skin tissue treated with positive control that showed a higher value. The standard deviations of the negative control (of which the OD values are used for the calculations) and test item treated tissues are all acceptable. Therefore, this deviation had no influence on the integrity of the study. The test item is irritant in the in vitro skin irritation test under the experimental conditions described in this report.

 

Eye irritation

An in vitro eye irritation study of the test item was performed in isolated chicken’s eyes. The irritation effects of the test item were evaluated according to the OECD TG 438 guideline and the classification scheme of Schutte et al (2009). After the zero reference measurements, the eyes were held in a horizontal position and the test item was applied onto the centre of the cornea such that the entire surface of the cornea was covered in all cases. After 10 seconds exposure time, the surface of the eyes was rinsed with physiological saline solution. Three eyes were treated with 30 μL test item. The three positive control eyes were treated in a similar way with 30 μL of 5% (w/v) Benzalkonium chloride solution. The negative control eye was treated with 30 μL of physiological saline (0.9% (w/v) NaCl solution). Corneal thickness, corneal opacity and fluorescein retention were measured and any morphological effects (e.g. pitting or loosening of the epithelium) were evaluated. The results from all eyes used in the study met the quality control standards. The negative control and positive control results were within the historical control data range in experiment. Thus, the study was considered to be valid. Slight corneal swelling change (mean = 12.6%) was observed during the four-hour observation period on test item treated eyes. Moderate cornea opacity change (severity 2 on two eyes and severity 3 on one eye) was observed. No significant fluorescein retention change (severity 0.5 on two eyes and no fluorescein retention change on one eye) was noted. Severe loosening of epithelium was observed in one eye at 75 minutes after the post treatment rinse. Due to the equivocal results of the Experiment I, an additional experiment was performed for clarification. In Experiment II slight corneal swelling change (mean = 16.6%) was observed during the four-hour observation period on test item treated eyes. Moderate cornea opacity change (severity 2 on all three eyes) was observed. Moderate fluorescein retention change (severity 0.5 on two eyes and no fluorescein retention change on one eye) was noted. Severe loosening of epithelium was observed in one eye at 75 minutes after the post treatment rinse. Based on this in vitro eye irritation assay in isolated chicken eyes with Ambrinol, according UN GHS Classification and to Schutte et al (2009), the test item is classed as Category 1.

Justification for classification or non-classification

Based on the results of the available in vitro skin studies, the substance has to be classified as Skin Irrit 2 and shall be labelled with H315: Causes skin irritation according to EU CLP (EC 1272/2008 and its amendments).

Based on the results of the available in vitro eye study, the substance has to be classified as Eye Damage 1 and shall be labelled with H318: Causes serious eye damage according to EU CLP (EC 1272/2008 and its amendments).