Cyclohexane, 1,4-bis(ethoxymethyl)-

Endpoint summary

Description of key information

Skin corrosion/irritation: 
- OECD 431 and 439: skin irritation potential
Eye damage/irritation:
- OECD 405: no eye irritating potential
- OECD 437: no ocular corrosion or severe irritation
- EpiOcular™: no eye irritation potential

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin corrosion/irritation:

A EpiDermTM Skin Corrosion / Irritation Test according to OECD 431 and 439 was performed to assess the potential of Cyclohexane, 1,4-bis(ethoxymethyl)- to cause dermal corrosion/irritation (BASF SE, 2013, 61V0766/12A492). Therfore, 50 μL (corrosion test) or 30 μL (irritation test) of the undiluted test substance was applied to a reconstructed three dimensional human epidermis model (EpiDerm™). For the corrosion test two EpiDerm™ tissue samples were incubated with the test substance for 3 minutes and 1 hour, respectively. The irritation test was performed with three EpiDerm™ tissue samples, which were incubated with the test substance for 1 hour followed by a 42-hours post-incubation period. Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as endpoint.

Results:

- Corrosion test: The mean viability of the test-substance treated tissues determined after an exposure period of 3 minutes was 91%, and it was 113% after an exposure period of 1 hour.

- Irritation test: The mean viability of the test-substance treated tissues determined after an exposure period of 1 hour with about 42 hours post-incubation was 9%.

Based on the observed results, Cyclohexane, 1,4-bis(ethoxymethyl)- shows a skin irritation potential in the EpiDerm™ skin corrosion/irritation test under the test conditions chosen.

Eye damage/irritation:

The potential of 1,4-bis(ethoxymethyl)-Cyclohexane 97% to cause damage to the conjunctiva, iris or cornea was assessed by a single ocular application of 0.1 mL of the undiluted test item to one eye of three New Zealand White rabbits (stepwise procedure starting with one animal and supplementing two additional animals). About, and not less than 24 hours after application the eye was rinsed with tap water.

The ocular reactions were assessed approximately 1, 24, 48 and 72 hours after application and in a weekly interval until day 7.

Additional eye examinations were performed at 24 and 48 h after application with the instillation of a fluorescein solution. Due to a negative finding at the 24 and 48 hour reading (no corneal lesions detectable with fluorescein) no further readings were performed with the aid of fluorescein.

The ocular reactions were reversible in all animals within 48 hours, 72 hours or 7 days after application, respectively.

Mean scores calculated for each animal over 24, 48 and 72 hours were 0.0, 0.0 and 0.0 for corneal opacity, 0.3, 0.0 and 0.0 for iris lesions, 1.0, 0.7 and 0.3 for redness of the conjunctiva and 0.7, 0.3 and 0.3 for chemosis.

Considering the described ocular reactions as well as the average score for irritation, 1,4-bis(ethoxymethyl)-Cyclohexane 97% does not show an eye irritating potential under the test conditions chosen.

A Bovine Corneal Opacity and Permeability Test (BCOP Test) according to OECD 437 was performed to assess the potential of Cyclohexane, 1,4-bis(ethoxymethyl)- to cause serious damage to the eyes (BASF SE, 2013, 63V0766/12V494). Therefore, 750 μL of the undiluted test substance was applied to the epithelial surface of isolated bovine corneas. Three corneas were treated with the test substance for 10 minutes followed by a 2-hours post-incubation period. In addition to the test substance a negative control (NC; de-ionized water) and a positive control (PC; 1% sodium hydroxide in de-ionized water) were applied to three corneas, each. Corneal opacity was measured quantitatively as the amount of light transmission through the cornea. Permeability was measured quantitatively as the amount of sodium fluorescein dye that passes across the full thickness of the cornea. Both measurements were used to calculate an In Vitro Irritancy Score of the test substance relative to the control corneas.

As a result, the Mean Opacity Value of the test substance was 5.1, the Mean Permeability Value 0.042 and the In Vitro Irritancy Score 5.7, respectively. Based on the observed results it was concluded, that Cyclohexane, 1,4-bis(ethoxymethyl)- does not cause ocular corrosion or severe irritation in the BCOP Test under the test conditions chosen.

The potential of Cyclohexane, 1,4-bis(ethoxymethyl)- to cause ocular irritation was assessed by a single topical application of 50 μL of the undiluted test substance to a reconstructed three dimensional human cornea model (EpiOcular™) (BASF SE, 2013, 62V0766/12A493). Two test runs were performed. Two EpiOcular™ tissue samples per test run were incubated with the test substance for 30 minutes followed by a 2-hours post-incubation period. Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability.

The mean viability of the test-substance treated tissues for the 1st test run was 60%. Based on this result (values for single tissues: 57.6% and 62.2%) the irritation potential could not be evaluated. Therefore a 2nd test run was performed. The mean viability of the test-substance treated tissues for the 2nd test run was 63% (values for single tissues: 62.1% and 64.5%).

Based on the observed results of the 1st and 2nd test run (mean viability of ca. 62%) it was concluded, that Cyclohexane, 1,4- bis(ethoxymethyl)- does not show an eye irritation potential in the EpiOcular™ eye irritation test under the test conditions chosen.

Justification for classification or non-classification

The present data on skin irritation fulfill the criteria laid down in regulation (EU) 1272/2008, and a classification as "skin irritant" (category 2) is warranted.

The present data on eye irritation do not fulfill the criteria laid down in regulation (EU) 1272/2008, and therefore, a non-classification is warranted.