Fatty acids, C18 unsaturated, ethyl & methyl esters

Endpoint summary

Description of key information

Skin irritation: Based on read-across from a structural analogue, Fatty acids, C18 unsaturated, ethyl & methyl esters has no skin irritating potential.
Eye irritation: No eye irritating potential.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

07 Apr - 29 Apr 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP guideline study, tested with the source substance Methyl linoleate (CAS No. 112-63-0). According to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

other: Kleinrussen, CHbb:HM

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Breeder Thomae GmbH, Biberach, Germany
- Age at study initiation: approx. 15 months
- Weight at study initiation: approx. 2600 g
- Housing: individual accommodation
- Diet (e.g. ad libitum): Ssniff rabbit diet K4 (Ssniff GmbH, Soest/D, Batch: 770392/02, 550492/O9) ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: at least 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-25
- Humidity (%): 45-70
- Air changes (per hr): 8
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

4h

Observation period:

1, 24, 48 and 72h; the observation period lasted 22 days

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: dorsal shaved skin, 6cm²
- Type of wrap if used: adhesive air- and vapour permeable gauze-patch which was fixed by a hypoallergenic adhesive gauze-bandage

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the relevant skin was cleaned from the residual test substance
- Time after start of exposure: 4h

SCORING SYSTEM: Draize

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: average 24, 48 and 72h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 22 days

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: average 24, 48 and 72h

Score:

2.67

Max. score:

4

Reversibility:

fully reversible within: 22 days

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: average 24, 48 and 72h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 14 days

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: average 24, 48 and 72h

Score:

1.33

Max. score:

4

Reversibility:

fully reversible within: 22 days

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: average 24, 48 and 72h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 22 days

Irritation parameter:

edema score

Basis:

animal #3

Time point:

other: average 24, 48 and 72h

Score:

1.33

Max. score:

4

Reversibility:

fully reversible within: 14 days

Irritant / corrosive response data:

The irritation effects of one experimental animal reversed within 7 days. The skin of this rabbit showed eschar. The observed effects of the other two experimental animals reversed completely within 22 days.

Table 1: Individual irritation scores

Skin effect	Erythema					Edema
Scoring	Scores at				Mean	Scores at				Mean
Animal No.	1h	24h	48h	72h	24-72h	1h	24h	48h	72h
1266/1	1	2	2	2	2.00	0	2	1	1	1.33
1297/1	1	2	3	3	2.67	0	1	2	3	2.00
1300/1	1	1	1	1	1.00	1	1	2	1	1.33

Linolsäure Methylester has not to be classified according to CLP. According to DSD it has to be classified as:

Xi, R38: Irritating to skin

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
(DSD: Xi, R38: Irritating to skin)

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:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with acceptable restrictions (purity: 80%)

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

(2012)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Version / remarks:

(1998)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

other: New Zealand albino

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Robinson Sevices (no further details)
- Age at study initiation: 11 weeks
- Weight at study initiation: 1956 - 2168 g
- Housing: individually housed in suspended stainless steel caging
- Diet: Harlan Teklad Global High Fiber Rabbit Diet #2031, a designated amount of the diet (approximately 150 g/day) and a Premium Timothy Cube (Ontario Dehy Inc.) were available to each rabbit
- Water: filtered tap water, ad lbitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 22
- Humidity (%): 53 - 56
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12 / 12

Vehicle:

unchanged (no vehicle)

Controls:

other: the untreated eye served as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL
Prior to instillation, 1 - 2 drops of ocular anesthetic (Tetracaine Hydrochloride Ophthalmic Solution USP, 0.5%) were placed into both the treated and control eye of each animal.

Duration of treatment / exposure:

single instillation (no washing)

Observation period (in vivo):

72 h
Reading time points: 1, 24, 48 and 72 h

Number of animals or in vitro replicates:

3 females

Details on study design:

SCORING SYSTEM: Draize

TOOL USED TO ASSESS SCORE: wight light source, fluorescein dye evaluation in the treated eye 24 h after administration

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

out of all 3 animals

Time point:

other: mean over 24, 48 and 72 h

Score:

0

Max. score:

3

Reversibility:

other: Reversibility: not applicable

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

out of all 3 animals

Time point:

other: mean over 24, 48 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: Reversibility: not applicable

Irritation parameter:

iris score

Basis:

mean

Remarks:

out of all 3 animals

Time point:

other: mean over 24, 48 and 72 h

Score:

0

Max. score:

2

Reversibility:

other: Reversibility: not applicable

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

out of all 3 animals

Time point:

other: mean over 24, 48 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: Reversibility: not applicable

Irritant / corrosive response data:

No local, occular effects indicative for eye irritation have been observed in any test animal at any reading time point.

Other effects:

All animals appeared active and healthy and gained body weight during the study. There was no ocular irritation or other signs of gross toxicity, adverse clinical effects, or abnormal behavior.

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Irritation

Justification for read-across

No data on skin irritation are available for Fatty acids, C18 unsaturated, ethyl & methyl esters whereas data regarding eye irritation are available for Fatty acids, C18 unsaturated, ethyl & methyl esters. In order to fulfil the standard data requirements regarding skin irritation defined in Regulation (EC) No 1907/2006, Annex VIII, 8.1, read-across to a structural analogue substance is conducted in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5.

According to Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met”. In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across) “to avoid the need to test every substance for every endpoint”.

Fatty acids, C18 unsaturated, ethyl & methyl esters is a multi-constituent substance specified by esters of ethanol and methanol with fatty acids C18 unsaturated (source canola oil) resulting in monoesters which meets the definition of an UVCB substance. Thus, the test substance represents fatty acid esters which undergo to a high extent hydrolysis by ubiquitous expressed gastrointestinal enzymes into the free fatty acid components and the respective alcohol moieties (Lehninger, 1970; Mattson and Volpenhein, 1972). Considering the common metabolism, the read-across approach is based on the presence of a common functional group, common precursors and the likelihood of common breakdown products via biological processes, which result in structurally similar chemicals with similar physico-chemical, toxicological and toxicokinetic behaviour. For further details on the read-across approach, please refer to the analogue justification in section 13 of the technical dossier.

As no data on skin irritation are available for Fatty acids, C18 unsaturated, ethyl & methyl esters, read-across to reliable data on the analogue substance Methyl linoleate (CAS 112-63-0) was conducted. Methyl linoleate (CAS 112-63-0) is a component of Fatty acids, C18 unsaturated, ethyl & methyl esters and is therefore regarded as a suitable analogue substance.

Skin Irritation

CAS 112-63-0

A primary dermal irritation study was performed with methyl linoleate (CAS 112-63-0) according to OECD Guideline 404 (Pittermann, 1992). The shaved dorsal skin of three Kleinrussen rabbits was exposed to 0.5 mL unchanged test material for 4 hours under semi-occlusive conditions. The rabbits were observed for 22 days. Skin reactions were assessed using the Draize scheme 1, 24, 48, 72 hours after removal of the test substance. After an exposure period of 4 hours slight to moderate erythema and edema were observed in all three animals. All irritation effects were fully reversible within 7 - 22 days following patch removal.

 

Eye irritation

An acute eye irritation study with EC 941-981-3 (purity: 80%) was performed according to OECD Guideline 405 with 3 female New Zealand albino rabbits (Slonina, 2015). One eye of the rabbits was exposed to 0.1 mL of the undiluted test substance and scored for eye reactions. The animals were observed for 72 h and scoring was performed 1, 24, 48 and 72 h after application. There was no conjunctival redness and no effects on conjunctival swelling, iris, or cornea observed at any reading time point.

 

Conclusion on skin and eye irritation properties

Skin and eye irritation properties have been investigated in vivo indicating no irritating properties of neither the target nor the analogue substance towards the skin or eyes. Therefore, based on these data, Fatty acids, C18 unsaturated, ethyl & methyl esters is not considered as skin or eye irritant.

A detailed reference list can be found in the CSR and in section 13 of the dossier.

Justification for selection of skin irritation / corrosion endpoint:
Hazard assessment is conducted by means of read-across from a structural analogue. The selected study is adequate and reliable based on the identified similarities in structure and intrinsic properties between source and target substance and overall quality assessment (refer to the endpoint discussion for further details).

Justification for selection of eye irritation endpoint:
The reliable GLP compliant OECD Guideline study was taken.

Justification for classification or non-classification

Based on available substance and analogue read-across data, the available data on skin and eye irritation do not meet the classification criteria according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.