5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-

Endpoint summary

Description of key information

Skin corrosion (OECD TG 431): the substance does not cause skin corrosion.

Skin irritation (OECD TG 439): the substance causes skin irritation.

In vitro eye irritation (OECD TG 492, 437, 405 in a WoE): The substance is not an eye irritant.

Respiratory irritation: the substance is not a respiratory irritant based on the results above and absence of human data.

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)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin corrosion

The substance was tested in vitro for skin corrosion in an EPISKIN Reconstructed Epidermis Model (OECD TG 431). Skin tissue was tested for direct MTT reduction before the start of the test. The substance was tested in duplicate on skin tissue at an amount of 20 mg. Sodium chloride (0.9% (w/v)) was used as vehicle. Sodium chloride (0.9% (w/v)) and glacial acetic acid were tested in duplicate as negative and positive control, respectively. Tissues were treated with the substance for an exposure time of 3, 60 and 240 minutes. The substance showed direct MTT reduction and therefore the viability assay was performed in parallel on viable and water-killed tissues. However, the results obtained showed a negligible degree of interference due to direct reduction of MTT and correction of the results was considered unnecessary. The relative mean viabilities of the test substance treated tissues were: 111.5%, 127.2% and 128.9% for the 3, 60 and 240 minutes exposure, respectively. Based on these findings, the substance is not corrosive to the skin.

Skin irritation

The substance was tested for skin irritation potential using the EPISKIN^TM Reconstructed Human Epidermis Model method (OECD TG 439). The substance was tested in triplicate at an amount of 10 mg (26.3 mg/cm^2). Sodium Dodecyl Sulphate (5% (w/v) and Phosphate Buffered Saline were tested in triplicate as positive and negative control, respectively. Tissues were treated with the substance for an exposure time of 15 minutes with a following post-incubation of 42 minutes. The substance showed direct MTT reduction and therefore the viability assay was performed in parallel on viable and water-killed tissues. However, the results obtained showed a negligible degree of interference due to direct reduction of MTT and correction of the results was considered unnecessary. The relative mean viability of the test substance treated tissues was 40%. The acceptance criteria for the assay were met and the assay was considered valid. Based on these findings, the substance is irritant to the skin.

Eye irritation

The substance was tested for eye irritation in two in vitro tests and one in vivo test. In a Weight of Evidence based on all available data it is concluded that the substance is not an eye irritant.

BCOP

The substance was tested for eye irritation in a BCOP test (OECD 437). Eye tissue was exposed to the substance, prepared as a 20% w/v solution in 0.9% w/v sodium chloride solution, for 240 minutes. Negative and positive controls were tested concurrently to confirm validity of the study. The IVIS for the test substance treated tissues was 30.0. Based on this result, no prediction of eye irritation can be made.

SkinEthic

Subsequently, the substance was tested for eye irritation using the SkinEthic reconstructed Human Corneal Epithelium model (OECD TG 492). The tissues were exposed to 30 mg of the substance for 10 minutes in triplicate. Phosphate buffered saline and sodium dodecyl saline were used as negative and positive control, respectively, and tested in triplicate to confirm the validity of the test. The substance directly reduced MTT and therefore the viability assay was performed in parallel on viable and freeze-killed tissues. However, the results obtained showed a negligible degree of MTT interference and therefore it was considered not necessary to correct the results. The relative mean viability of the test substance treated tissues was 100.7%. Based on this result, the substance is not eye irritating.

Eye irritation in vivo

Following the inconclusive and negative results in the in vitro studies, the substance was tested in an in vivo acute eye irritation study (OECD TG 405). One male and one female rabbit were exposed using a single application to approximately 96 mg of the substance. Diffuse corneal opacity was noted in one treated eye at the 24, 48 and 72-Hour observations. Iridial inflammation was noted in both treated eyes 1 and 24 hours after treatment and in one treated eye at the 48 Hour observation. Moderate conjunctival irritation was noted in both treated eyes 1 and 24 hours after treatment.  Moderate conjunctival irritation was noted in one treated eye and minimal conjunctival irritation was noted in the other treated eye at the 48 Hour observation with minimal conjunctival irritation noted in both treated eyes at the 72 Hour observation. Mean conjunctivae scores (24/48/72 h) were 2 and 1.33 for the male and female, respectively. Mean chemosis scores (24/48/72 h) were 1.33 for both male and female animals. Both treated eyes appeared normal at the 7 Day observation.

The substance is not an eye irritant based on the following reasoning from EU CLP: Substances should produce positive responses in at least 2 out of 3 animals. Positive responses are considered to be(a) corneal opacity ≥ 1; and/or (b) iritis ≥ 1; and/or (c) conjunctival redness ≥ 2; and/or (d) conjunctival oedema (chemosis) ≥ 2 calculated as the mean scores following grading at 24, 48 and 72 hours after instillation of the test material, and which fully reverses within an observation period of normally 21 days. Cornea effects of 1 was seen in one animal and redness of 2 was seen in the same animal. For a single cornea effect or a single redness effect the substance does not need to be classified and therefore the substance is not an eye irritant.

WoE for eye irritation

Using a Weight of Evidence approach, these three studies are evaluated together:

- Based on the results of the BCOP study, no prediction for eye irritation could be made.

- In the SkinEthic study the substance was not an eye irritant.

- The in vivo study was considered negative: cornea effects of 1 was only seen in one animal and redness of 2 was seen in the same animal. For a single cornea effect or a single redness effect the substance does not need to be classified. Based on this, the SkinEthic study (OECD TG 492) is considered the key study and the substance should not be classified for eye irritation.

Respiratory irritation

There are no occupational or consumer data indicating respiratory tract irritation. There are also no relevant experimental guidelines or results available that indicate respiratory irritation. Therefore respiratory irritation is not anticipated. The ECHA guidance (R7a: 7.2.12.1, 2017) presents that respiratory irritation may be indicated when the substance is a severe irritant. The substance is a skin irritant but not corrosive, it is not an eye irritant and in absence of human data the substance does not need to be classified as a respiratory irritant.

Justification for classification or non-classification

The substance has to be classified as skin irritation category 2 and shall be labelled with H315: Causes skin irritation according to EU CLP (EC no. 1272/2008 and its amendments).

The substance does not have to be classified for eye irritation or respiratory irritation according to EU CLP (EC no. 1272/2008 and its amendments).