Fatty acids, C18-(unsaturated) dimers and their monoesters and diesters with 2-ethylhexanol

Endpoint summary

Description of key information

SKIN IRRITATION
The skin irritation properties of 400160 were investigated in an in vitro skin irritation test (Reconstructed human epidermis model test). This test is a stand-alone replacement test for in vivo skin irritation testing. Hence, no in vivo study was conducted. The result of the in vitro study indicated no skin irritation potential. 
EYE IRRITATION 
The eye irritation properties of 400160 were assessed in an in vitro study (BCOP) and in an in vivo study (Draize test). No irritating effects could be observed in the in vitro study. A slight to moderate redness and chemosis was noted in the in vivo study which was totally reversible.
RESPIRATORY IRRITATION
The respiratory irritation of 400160 was not studied.

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/corrosion in vitro

An in-vitro study human skin model test (EU method B.46) was performed in order to evaluate the potential of 400160 to evoke skin irritation in a human skin model. 400160 was spread on the surface of three sections of an EpiDermTM tissue and incubated for 60 min. The negative control consisting of Dulbecco’s phosphate buffered saline was applied to another three tissue sections. As positive control a SDS solution (50 g/L) was used for three other tissue sections. An enzyme assay with MTT-reagent to determine cell viability was performed. The mean percentage values of formazan production were calculated in comparison to the negative control. The relative absorbance values were increased to 100.9% after the treatment with 400160. This value is well above the threshold for irritation (50%). The positive control showed a reduction of formazan production of 6.5%. In conclusion, it can be stated that the test item 400160 is considered as not skin irritant under the experimental conditions used in this study.

Skin irritation/corrosion in vivo

According to Annex VIII section 8.1.1., an in vivo skin irritation test does not have to be conducted when an acute toxicity study by the dermal route does not indicate skin irritation up to the limit dose level (2000 mg/kg bw). 400160 does not show any signs of skin irritation/corrosion in a relevant dermal toxicity test (see section 7.2.3. of this IUCLID file). The test was performed as limit test (2000 mg/kg bw).

Furthermore, the skin irritation potential of 400160 was determined in vitro using the “reconstructed human epidermis test method” according to OECD guideline 439. According to OECD guideline 439 par. 1 this test method can be used to determine the skin irritancy of chemicals as a stand-alone replacement test for in vivo skin irritation testing. Therefore, the in vivo skin irritation test can be waived due to animal welfare concerns.

Eye irritation in vitro

The BCOP test (OECD GL 437) was performed to assess the corneal irritation and damage potential of 400160 by quantitative measurements of changes in opacity and permeability in a bovine cornea. The test item solution in olive oil (10% w/v) was brought onto the cornea of a bovine eye which previously had been incubated with cMEM ( = complete Minimum Essential Medium) without Phenol red at 32±1°C for 1 h and whose opacity had been determined. The test item was incubated on the cornea for 10 min at 32±1°C. After removal of the test item solution, opacity and permeability values were measured. Physiological sodium chloride solution was used as negative control, olive oil was used as solvent control. The negative control and the solvent control showed no irritating effect on the corneas. 10% sodium hydroxide solution was used as positive control. The positive control induced severe irritation on the cornea, mean IVIS was 166.67. The negative control showed no irritation, mean IVIS was 0.81. For the test item solution, a mean IVIS of 0.6790 was calculated, corresponding to a classification as not eye irritant.

Eye irritation in vivo

The eye irritation properties of 400160 were tested according to OECD guideline 405. 0.1 mL of the test item was instilled into the conjunctival sac of one eye of young adult New Zealand White rabbits (3/male). Animals then were observed for 3 d, and in addition after 7 d to confirm reversibility. Irritation was scored according to the EU guideline. The conjunctivae reactions observed during the study were slight to moderate and totally reversible in the three animals: a slight to moderate redness noted 1 h after the test item instillation was totally reversible between d 3 and 7; a slight to moderate chemosis noted 1 h after the test item instillation was totally reversible between d 2 and 3. Therefore, 400160 is not an eye irritant and do not have to be classified.

Justification for selection of skin irritation / corrosion endpoint:
In vivo test as stand-alone replacement test for in vivo skin irritation test.

Justification for selection of eye irritation endpoint:
In vivo test is more conclusive than in vitro test.

Justification for classification or non-classification

Based on the results of the skin and eye irritation studies given above, 400160 is not classified as skin or eye irritant according to the current EU-CLP regulation.

A classification of 400160 for respiratory irritation is not possible, as no respiratory irritation study was conducted.