Hexanamide, N-(2-hydroxyethyl)-3,5,5-trimethyl-

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Considering the results of the in vitro skin irritation/corrosion studies, the test substance can be considered to be irritating to skin. However, in the absence of data and based on the available weight of evidence from the skin irritation and the surface tension studies, the test substance is considered to be corrosive to the eyes as a conservative approach.

Endpoint conclusion:

adverse effect observed (irritating)

Endpoint conclusion:

adverse effect observed (irreversible damage)

Endpoint conclusion:

no study available

Skin

Study1: A study was conducted to determine dermal irritation potential of the test substance, in anEpiSkin®in vitro irritation test, according to OECD 439, in compliance with GLP. Prior to the conduct of the irritation assay, a preliminary test was conducted to assess the intrinsic ability of the test substance to reduce methylthiazoldiphenyl-tetrazolium bromide (MTT) to formazan. The test substance did not reduce MTT to formazan. The dermal irritation potential was assessed by applying 10 μL of the test substance to the exposed surface of three EpiSkin tissues for 15 min. The surface area of the EpiSkin was 0.38 cm2, therefore the application rate was 26.3 μL/cm2. After the 15 min exposure period, the test substance was washed from the surface of the EpiSkin using Dulbecco’s phosphate-buffered saline (PBS). The EpiSkin tissues were then incubated for a recovery period of 42 h in a humidified incubator, set to maintain temperature and CO2 levels of 37°C and 5%, respectively. Following incubation, the tissues were transferred to assay medium containing MTT (0.3 mg/mL) and returned to the incubator for 3 h. Biopsies of the EpiSkin membranes were removed, added to acidified isopropanol, and refrigerated for ca 68 h in order to extract the formazan. The formazan production (cell viability) was assessed by measuring the optical density of the extracts at a wavelength of 550 nm. Three replicates of the positive control, aqueous sodium dodecyl sulphate (SDS) solution (5%, w/v), and the negative control, PBS, were tested in parallel to demonstrate the efficacy of the assay. The viability of each individual EpiSkin tissue was calculated as a percentage of the mean negative control viability (defined as 100%). Exposure to the test substance resulted in a mean EpiSkin viability of 9.56% ± 3.26% of the negative control value. Exposure to the positive control, aqueous SDS solution (5%, w/v), resulted in a mean EpiSkin viability of 13.36% of the negative control value. Under the conditions of the in vitroEpiSkin®study, the test substance was demonstrated to be an irritant to skin (Blackstock, 2013).

Study 2:

A study was conducted to determine the skin corrosion potential of the test substance in an in vitro Reconstructed Human Epidermis (RHE) test,according to OECD Guideline 431 and EU Method B.40 bis in compliance with GLP. In the study, two tissues of the human skin model EpiDerm^TM were treated with the test substancefor 3 minutes and 1 hour, respectively. The test substance was applied to each tissue and spread to match the tissue size. Demineralised water was used as negative control and 8 M KOH was used as positive control. After treatment, the respective substance was rinsed from the tissues. Then, cell viability of the tissues was evaluated by addition of MTT, which can be reduced to a blue formazan. Formazan production was evaluated by measuring the optical density (OD) of the resulting solution. Skin corrosion was expressed as the remaining cell viability after exposure to the test substance. After treatment with the negative control, the absorbance values were within the required acceptability criterion of mean OD ≥ 0.8 and ≤ 2.8 for both treatment intervals thus showing that the quality of the tissues was adequate for the testing. The OD was 1.609 (3 minutes experiment) and 1.681 (1 h experiment). The positive control showed clear corrosive effects for both treatment intervals. The mean relative tissue viability value was reduced to 4.5% for the 1 h treatment. After 3 minutes and 1 h treatment with the test substance, the mean value of relative tissue viability was increased to 102.1 and 51.2% respectively. These values were above the respective thresholds for corrosion potential (i.e., 50 and 15%). Therefore, under the conditions of the RHE study, the test substance was considered to be non-corrosive to skin (Himmelsbach, 2021)

Eye:

No study was available for eye irritation. However, considering the surface-active nature of the test substance and the skin irritation results, the test substance can be considered to cause serious eye damage as a conservative approach and in accordance with Annex XI, Section 1.2 (weight of evidence) of the REACH regulation.

Based on the results of the in vitro skin irritation/corrosion studies, the test substance warrants a Skin Irrit. 2; H315: ‘Causes skin irritation’ classifications according to EU CLP (EC 1272/2008) criteria. Further based on the available weight of evidence and as a conservative approach, the test substance has been classified as Eye Damage 1; H318: 'Causes serious eye damage'.

Cross-reference 2

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

The surface tension of the test substance was determined using the ring method according to OECD TG 115 (Sohar, 2013).

Saturated solution in deionized water (1g/L) has a surface tension of 37.2 mN/m at 23°C.