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Description of key information

The available information on 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3)  provides no indication for skin irritating properties in the in vitro skin irritation study (EpiDerm™ test). No eye irritating potential was demonstrated in two in vitro eye irritation studies (EpiOcular™ and BCOP test) with 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3). 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Skin irritation

In the chosen key study according to OECD TG 439 and GLP, he potential of 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) to cause dermal irritation was assessed by a single topical application of 25 μL bulk volume of the undiluted test item to a reconstructed three dimensional human epidermis model (EpiDerm™) (BASF SE (2012), 61V0473/11A562). Three EpiDerm™ tissue samples were incubated with the test item for 1 hour followed by a 42‑hours post-incubation period. Tissue destruction was determined by measuring the metabolic activity of the tissue after test item exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, quantitatively measured by reduced Formazan production after incubation with MTT, was chosen as endpoint. The Formazan production of the test item‑treated epidermal tissues was assessed spectrophotometricallyviathe optical density at 570 nm and compared to that of negative control (NC) tissues concurrently applied with 30 µL PBS. The quotient of both values indicated the relative tissue viability. In this in vitro test system, irritant potential of the test item was predicted if the mean relative viability of test item‑treated tissues was ≤ 50 % as compared with the viability of concurrent NC tissues. Sodium dodecyl sulfate in water (SDS, 5 % w/v) was used as positive control (PC) item.

The mean viability of the test item-treated tissues determined after an exposure period of 1 hour with about 42 hours post-incubation was 101 %. The test item was not able to reduce MTT directly. Yellow discoloration of the tissues was observed after washing. The PC item demonstrated appropriate sensitivity (relative viability ≤ 20 %) of the tissues. Under the conditions of this in vitro study, the test item did not show a skin irritation potential in the EpiDerm™ skin irritation test. On the basis of this validated stand-alone in vitro test, 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) is not considered to be irritating to skin.

 

Eye irritation

The potential of 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) to cause serious damage to the eyes was assessed by a single topical application of 750μL of a 20 % aqueous test item preparation to the epithelial surface of isolated bovine corneas (BCOP test according to OECD TG 439 and GLP; BASF SE (2012), 63V0473/11A563). Three corneas were treated with this preparation for an exposure period of 4 hours. Deionised water served as negative control item (NC) and 20 % (w/v) Imidazole in deionised water served as positive control item (PC), applied to three corneas each. Corneal opacity was measured quantitatively as the amount of light transmission through the cornea using an opacitometer. Permeability was measured quantitatively as the amount of Sodium fluorescein dye that passed across the full thickness of the cornea by spectrophotometrical determination of the optical density at 490 nm. Both measurements were used to calculate an in vitro irritancy score (IVIS) of the test item relative to the control corneas. The IVIS value of the test item did not indicate a test item‑related risk of serious damage to eyes. The PC item demonstrated appropriate sensitivity of the test system. 

Under the conditions of this study, 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) did not cause serious eye damage in the BCOP test.

 

The potential of the test item to cause ocular irritation was assessed in a second in vitro study by a single topical application of 50μL bulk volume (about 8 mg) of the undiluted test item to a reconstructed three dimensional human cornea model (EpiOcular™, BASF SE (2012), 62V0473/11A564). Two EpiOcular™ tissue samples were incubated with the test item for 90 min followed by a 18-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 MTT, was chosen as endpoint. The Formazan production of test item treated epidermal tissues was assessed spectrophotometrically via the optical density at 570 nm and compared to that of negative control (NC) tissues concurrently treated with 50 µL of deionised water. The quotient of the values indicated the relative tissue viability. The test item was considered as irritant, if the mean relative tissue viability of the test item treated tissues was ≤ 50 %. Methyl acetate at a volume of 50 µL was used as positive control (PC) item.

The mean viability of the test item treated tissues determined after an exposure period of 90 min with about 18 hours post-incubation was 104 %. The test item was not able to reduce MTT directly. Yellow discoloration of the tissues was observed after washing. The PC item demonstrated appropriate sensitivity of the tissues. Under the experimental conditions employed, the test item did not show an eye irritation potential in the EpiOcular™ eye irritation test.

On this basis and with special regard to the results of the BCOP test (BASF SE (2012), 63V0473/11A563), 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)-cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) is not considered irritating to the eye in a weight of evidence.

 

 

Justification for classification or non-classification

The present data on skin and eye irritation do not fulfill the criteria laid down in 67/548/EEC and regulation (EU) 1272/2008, and therefore, a non-classification is warranted.