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Description of key information

• Non-irritating to skin (OECD 439, read-across)
• Non-irritating to eyes (valid in vitro methods and OECD 405, read-across)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Read-across from GLP guideline study. Read-across justification: A comparison of the read across substance (9DAME) and the target substance (ODDAME) shows that the two substances share structural similarities, increasing from a chain length of C10 to C18 with similar functional groups. See attahced for 'read across jusification' for ODDAME.
Qualifier:
according to guideline
Guideline:
other: OECD Guideline 439 (In vitro skin irritation: reconstructed human epidermis test method)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test system:
human skin model
Justification for test system used:
The Episkin model is a three-dimensional reconstructed human epidermis model consisting of adult human-derived epidermal keratinocytes seeded on a dermal substitute consisting of a collagen type I matrix loaded with type IV collagen. A highly differentiated and stratified epidermis model is obtained after a 13-day culture period comprising the main basal, supra basal, spinous and granular layers and a functional stratum corneum.
Vehicle:
unchanged (no vehicle)
Details on test system:
See any other information on materials and methods section.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
10 μL
Duration of treatment / exposure:
15 minutes
Duration of post-treatment incubation (if applicable):
42 hours
Number of replicates:
3
Vehicle:
not specified
Irritation / corrosion parameter:
other: other: relative viability of treated tissues
Run / experiment:
Mean
Value:
68.8
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other:
Remarks:
Basis: mean. Time point: 15 minutes. Remarks: ± 13.7 Percent .

DIRECT MTT REDUCTION

- The MTT solution containing the test item did not turn blue, which indicated that the test material did not directly reduce MTT.

 

TEST MATERIAL, POSITIVE CONTROL AND NEGATIVE CONTROL

- Individual and mean OD540 values, standard deviations and tissue viabilities for the test material, negative control and positive control are shown in Table 1 (attached).

- Mean viabilities and standard deviation of the test material and positive control relative to the negative control are also given in Table 1 (attached).

 

QUALITY CRITERIA

- Relative mean tissue viability for the positive control treated tissues was 4.5 % relative to the negative control treated tissues and the standard deviation value of the percentage viability was 1.4 %. The positive control acceptance criterion was therefore satisfied.

- Mean OD540 for the negative control treated tissues was 0.927 and the standard deviation value of the percentage viability was 8.7 %. The negative control acceptance criterion was therefore satisfied.

- Standard deviation calculated from individual percentage tissue viabilities of the three identically treated tissues was 13.7 %. The test item acceptance criterion was therefore satisfied.

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test material was determined to be non-irritant.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Read-across from a GLP guideline study. Read-across justification: A comparison of the read-across substance (9DAME) and the target substance (ODDAME) shows that the two substances share structural similarities, increasing from a chain length of C10 to C18 with similar functional groups. See attahced for 'read across jusification' for ODDAME.
Qualifier:
according to guideline
Guideline:
OECD Guideline 405 (Acute Eye Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Species:
rabbit
Strain:
New Zealand White
Details on test animals or tissues and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Leicestershire, UK
- Age at study initiation: 12-20 weeks
- Weight at study initiation: 2.23 or 2.26 kg
- Housing: The animals were individually housed in suspended cages.
- Diet: 2930C Teklad Global Rabbit diet available ad libitum.
- Water: Mains drinking water available ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-23 °C
- Humidity (%): 30-70%
- Air changes: at least 15 changes per hour
- Photoperiod: 12 hrs dark / 12 hrs light (06:00 to 18:00)
Vehicle:
unchanged (no vehicle)
Controls:
yes
Amount / concentration applied:
TEST MATERIAL
- Amount applied: 0.1 mL of the test item was placed into the conjunctival sac of the right eye. The upper and lower lids were held close together for about 1 second immediately after treatment to prevent loss of the test item, and then released.
Observation period (in vivo):
72 hours
Number of animals or in vitro replicates:
One animal was treated initially. After consideration of the ocular responses produced in the first animal, two additional animals were treated.
Details on study design:
CONTROLS
The left eye remained untreated and was used for control purposes.

REMOVAL OF TEST SUBSTANCE
- Washing: none

SCORING SYSTEM: Immediately after administration of the test item, an assessment of the initial pain reaction was made according to the 6 point scale shown in Appendix 1 (see section "Attached background material"). Assessment of ocular damage/ irritation was made approximately 1 hour and 24, 48 and 72 hours following treatment according to Draize (see Appendix 2 in section "Attached background material")

TOOL USED TO ASSESS SCORE: light source from a standard ophthalmoscope

BODYWEIGHT
Individual bodyweights were recorded on Day 0 (the day of dosing) and at the end of the observation period.
Irritation parameter:
cornea opacity score
Basis:
animal: 1, 2 and 3
Time point:
other: 1-72 hours
Score:
0
Max. score:
4
Remarks on result:
other: All scores were 0
Irritation parameter:
iris score
Basis:
animal: 1, 2 and 3
Time point:
other: 1-72 hours
Score:
0
Max. score:
2
Remarks on result:
other: All scores were 0
Irritation parameter:
other: conjuctivae redness score
Basis:
animal #1
Time point:
other: Mean of 24 h, 48 h and 72 h scores
Score:
0.33
Max. score:
3
Reversibility:
fully reversible within: 48 hours
Irritation parameter:
other: conjuctivae redness score
Basis:
animal #2
Time point:
other: Mean of 24 h, 48 h and 72 h scores
Score:
0.67
Max. score:
3
Reversibility:
fully reversible within: 72 hours
Irritation parameter:
other: conjuctivae redness score
Basis:
animal #3
Time point:
other: Mean of 24 h, 48 h and 72 h scores
Score:
0.67
Max. score:
3
Reversibility:
fully reversible within: 72 hours
Irritation parameter:
other: conjuctivae chemosis score
Basis:
animal #1
Time point:
other: Mean of 24 h, 48 h and 72 h scores
Score:
0.33
Max. score:
4
Reversibility:
fully reversible within: 48 hours
Irritation parameter:
other: conjuctivae chemosis score
Basis:
animal #2
Time point:
other: Mean of 24 h, 48 h and 72 h scores
Score:
0.33
Max. score:
4
Reversibility:
fully reversible within: 48 hours
Irritation parameter:
other: conjuctivae chemosis score
Basis:
animal #3
Time point:
other: Mean of 24 h, 48 h and 72 h scores
Score:
0.33
Max. score:
4
Reversibility:
fully reversible within: 48 hours
Irritant / corrosive response data:
No corneal or iridial effects were noted during the study.

Moderate conjunctival irritation was noted in all treated eyes one hour after treatment. Minimal conjunctival irritation was noted in all treated eyes at the 24 hour observation and in two treated eyes at the 48 hour observation.

One treated eye appeared normal at the 48 hour observation and two treated eyes appeared normal at the 72 hour observation.

The individual results are detailed in Table 2.
Other effects:
Bodyweight loss was noted in one animal and two animals showed expected gain in bodyweight during the study.

Table 2: Individual scores for ocular irritation

Rabbit number and sex

71614 Male

71646 Male

71647 Male

IPR = 2

IPR = 2

IPR = 2

Time after treatment

1

hour

24

hours

48

hours

72

hours

1

hour

24

hours

48

hours

72

hours

1

hour

24

hours

48

hours

72

hours

Cornea

Degree of opacity

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

Area

0

0

0

0

0

0

0

0

0

0

0

0

Iris

0

0

0

0

0

0

0

0

0

0

0

0

Conjunctivae

Redness

 

2

 

1

 

0

 

0

 

2

 

1

 

1

 

0

 

2

 

1

 

1

 

0

Chemosis

2

1

0

0

2

1

0

0

2

1

0

0

Discharge

2

1

0

0

2

1

0

0

2

1

0

0

IPR = initial pain reaction

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test item is considered to be not irritating to the rabbit eye and is not classified in accordance with CLP Regulation No (EC) 1272/2008.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Additional information

The skin and eye irritation potential of the test item octadecanedioic acid, 1,18-dimethyl ester (ODDAME) has been read-across from the substance 9-decenoic acid, methyl ester (9DAME) from the following studies.

Skin irritation:

A reliable in vitro study was performed in accordance with GLP and OECD Guideline 439 to evaluate the skin irritation potential of 9-decenoic acid, methyl ester using the EPISKIN™ reconstructed human epidermis model after a treatment period of 15 minutes followed by a post-exposure incubation period of 42 hours (Harlan Laboratories Ltd, 2012). The relative mean viability of the test item treated tissues was 68.8 % after the 15 minute exposure period. The test item, 9-decenoic acid, methyl ester was therefore considered to be non-irritant.

In vitro skin irritation studies performed in accordance with OECD Guideline 439 are considered to be valid replacements for the in vivo skin irritation study (OECD Guideline 404). The result of this study on 9-decenoic acid, methyl ester indicates that the test material is not a skin irritant and is considered to be valid without the need to verify the result by performing additional in vivo studies.

Eye irritation:

A reliable in vitro study was performed in accordance with GLP and to accepted scientific standards (Harlan Laboratories Ltd, 2012). The purpose of the study was to determine the eye irritation potential of 9-decenoic acid, methyl ester using the SkinEthic reconstructed Human Corneal Epithelium model after a treatment period of 10 minutes. Triplicate SkinEthic tissues were treated with 30 µL of the test item for 10 minutes. Cytotoxicity was determined by the reduction of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to formazan by viable cells in the test item treated tissues (quantitative measurement of tissue viability) relative to the negative control. The relative mean viability of the test item treated tissues was 113.5% and hence 9-decenoic acid, methyl ester is considered to be a non-irritant. A confirmatory in vivo test was therefore performed.

 

A reliable in vivo study was performed in accordance with GLP and OECD Guideline 405 to assess the irritancy potential of 9-decenoic acid, methyl ester to the eye of the New Zealand white rabbit (Harlan Laboratories Ltd, 2012). A single application of the test item to the non-irrigated eye of three rabbits produced moderate conjunctival irritation. One treated eye appeared normal at the 48 hour observation and two treated eyes appeared normal at the 72 hour observation. Based on the classification criteria for eye irritation according to Regulation (EC) No. 1272/2008, 9-decenoic acid, methyl ester is considered to be non-irritating to eyes.


Justification for classification or non-classification

The skin and eye irritation potential of the test item octadecanedioic acid, 1,18-dimethyl ester (ODDAME) has been read-across from the substance 9 -decenoic acid, methyl ester. In the in vitro skin irritation, the in vitro eye irritation and the in vivo eye irritation studies, 9-decenoic acid, methyl ester was non-irritant. Therefore the substance octadecanedioic acid, 1,18-dimethyl ester (ODDAME) is also be considered a non-irritant according to Regulation (EC) No. 1272/2008.