Methyl dodec-9-enoate

Endpoint summary

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:

2011-11-15 to 2011-11-21

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 target substance (9DDAME) and the read-across substance (9DAME) shows that the two substances share structural similarities, increasing from a chain length of C10 to C12 with similar functional groups and also have ‘mechanistic action’ similarities.

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)

Remarks:

Date of inspection 2011-07-19 to 2011-07-21; Date of signature 2011-08-31

Species:

other: not applicable

Strain:

not specified

Details on test animals or test system and environmental conditions:

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.

Type of coverage:

other: not applicable

Preparation of test site:

other: not applicable

Vehicle:

not specified

Controls:

other: not applicable

Amount / concentration applied:

10 μL

Duration of treatment / exposure:

15 minutes

Observation period:

Not applicable

Number of animals:

Not applicable

Details on study design:

MTT DYE METABOLISM, CELL VIABILITY ASSAY
- The MTT assay is a colourmetric method of determining cell viability based on reduction of the yellow tetrazolium salt (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to a blue formazan dye by mitochondrial succinate dehydrogenase in viable cells.
- One limitation of the assay is possible interference of the test material with MTT. A test item may directly reduce MTT, thus mimicking dehydrogenase activity of the cellular mitochondria. This property of the test item is only a problem if, at the time of the MTT test (after rinsing), there are still sufficient amounts of the test item present on or in the tissues. In this case, the true metabolic MTT reduction and the false direct MTT reduction can be differentiated and quantified.

Irritation / corrosion parameter:

other: other: relative viability of treated tissues

Value:

68.8

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 15 minutes. Remarks: ± 13.7 Percent . (migrated information)

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:

23 January 2012 to 02 February 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 target substance (9DDAME) and the read-across substance (9DAME) shows that the two substances share structural similarities, increasing from a chain length of C10 to C12 with similar functional groups and also have ‘mechanistic action’ similarities.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection 2011-07-19 to 2011-07-21; Date of signature 2011-08-31

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

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

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

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

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

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

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

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

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 9-dodecenoic acid, methyl ester (9DDAME) 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 of read-across: A comparison of target substance (9DDAME) and the read-across substance (9DAME) shows that the two substances share structural similarities, increasing from a chain length of C10 to C12 with similar functional groups and also have ‘mechanistic action’ similarities.

Justification for selection of skin irritation / corrosion endpoint:
The skin irritation/ corrosion potential of the test item 9-dodecenoic acid, methyl ester (9DDAME) has been read-across from a study conducted with the substance 9-decenoic acid, methyl ester (9DAME). The study was conducted according to OECD Guideline 439 and to GLP and is adequately reported. As such the study a been assigned a reliability 1.

Justification for selection of eye irritation endpoint:
The eye irritation potential of the test item 9-dodecenoic acid, methyl ester (9DDAME) has been read-across from a study conducted with the substance 9-decenoic acid, methyl ester (9DAME). The study was conducted according to OECD Guideline 405 and to GLP and is adequately reported. As such the study as been assigned a reliability 1

Justification for classification or non-classification

The skin and eye irritation potential of the test item 9 -dodecenoic acid, methyl ester 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 9-Dodecenoic acid, methyl ester is also be considered a non-irritant according to Regulation (EC) No. 1272/2008.