Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, 2-ethylhexyl ester

Endpoint summary

Description of key information

The test article caused mild reactions in both skin and eye irritation studies with rabbits. The scores were well below the regulatory threshold and the test article is considered to be not irritating.

The structural analogue substance was found to cause mild transient irritating effects on skin and eyes in rabbits, as tested in GLP and OECD testing guideline compliant studies. Effects were below the threshold of classification and labelling.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 13th, 1989 to June 16th, 1989.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

1981

Deviations:

no

Principles of method if other than guideline:

The study was performed according to the OECD TG 404 and to GLP, however with following deviation: testing was conducted under occlusive conditions instead of semiocclusive as recommended by the guideline.

GLP compliance:

yes

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Kleintierfarm Madoerin AG, CH-4414 Fuellinsdorf
- Age at study initiation: approximately 12-14 weeks
- Weight at study initiation: 2290-2380 g
- Housing: individually in metal cages (and identified by individually numbered ear tags)
- Diet: standard rabbit pellet (Nafag No. 814, Gossau, Switzerland) ad libitum
- Water: fresh water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20 +/- 3°C
- Humidity: 30-70%
- Photoperiod (hrs dark / hrs light): 12h / 12h

All batches of the diet are assayed for nutritive ingredients and contaminant level by the manufacturer.
The drinking water quality fulfilled the critical parameters in the specification of the "Schweizerisches Lebensmittelbuch" (Edition 1972).

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

other: A control gauze patch moistened with distilled water was applied to the contralateral flank.

Amount / concentration applied:

A gauze patch (approx. 12-16 cm ) bearing 0.5 mL of the test substance was applied to the right flank of each animal. The patches were loosely covered with an aluminum foil and held in place for 4 hours by an adhesive tape (Isoplast, Isoplast AG, CH-5200 Brugg).

Duration of treatment / exposure:

4 hours

Observation period:

The skin reactions were evaluated 1, 24, 48, and 72 hours after removing the gauze patches; skin reaction was assessed according to the OECD scoring system. Moreover, the animals were checked daily for systemic symptoms and mortality.

Number of animals:

3 male animals.

Irritation parameter:

erythema score

Basis:

mean

Remarks:

n = 3

Time point:

24/48/72 h

Score:

0.1

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: Erythema graded 1 was seen in all 3 animals at reading time point 1 hour and persisted until 24 hours in only one case. After 48 hours, recovery was complete.

Irritation parameter:

edema score

Basis:

mean

Remarks:

n = 3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: None of the animals showed edema.

Irritant / corrosive response data:

The substance applied for 4 hours to the skin of rabbit under occlusive conditions induced very slight erythema in all 3 animals but no edema. Erythema was seen at reading time point 1 hour following removal of the dressing and was graded 1(max. 4). At reading time point 24 hour, very slight erythema persisted in one of the 3 animals. At reading time point 48 hour, reversibility was completed in all 3 animals.

Other effects:

None

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions employed the test article induced minimal erythema reactions well below the threshold of significance when applied to the clipped albino rabbit skin.

Executive summary:

The substance was applied for 4 hours to the skin of 3 male rabbits according to the OECD TG 404, but under occlusive conditions. The treatment induced very slight erythema in all 3 animals but no edema. Erythema was seen at reading time point 1 hour following removal of the dressing and was graded 1(max. 4). At reading time point 24 hour, very slight erythema persisted in one of the 3 animals. At reading time point 48 hour, reversibility was completed in all 3 animals. Based on the scoring of the skin findings as recommended by the OECD guideline, the test item was not irritating to the skin of rabbit.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 23, 2017 - January 24, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

other: Japan MAFF Testing Guideline of 12 Nousan No. 8147, November 24, 2000 as this is in line with OECD 405

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga GmbH, Germany
- Age at study initiation: Approx.3 months
- Weight at study initiation: 2.62 kg – 2.83 kg
- Housing: Single housing, atainless steel wire mesh cages with grating with shallow cage body; floor area: 4225 cm2
- Diet: STANRAB (P) SQC; SDS Special Diets Services, 67122 Altrip, Germany, ad libitum
- Water: Tap water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20°C ± 3°
- Humidity (%): 30-70
- Air changes (per hr): approx. 10
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

other: the untreated eye was used as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL

Duration of treatment / exposure:

single instillation

Observation period (in vivo):

72 hours

Number of animals or in vitro replicates:

3 females

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes, with tap water
- Time after start of exposure: 24 h


SCORING SYSTEM: according to OECD guideline

TOOL USED TO ASSESS SCORE: fluorescein solution

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

1

Reversibility:

fully reversible within: 24 h

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.7

Max. score:

2

Reversibility:

fully reversible within: 72 h

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.7

Max. score:

2

Reversibility:

fully reversible within: 72 h

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

1

Reversibility:

fully reversible within: 24 h

Irritant / corrosive response data:

Neither corneal nor iris lesions were noted in all animals at any examination time point. Even after instillation of a fluorescein solution no corneal lesions were detectable after 24 and 48 hours.
Slight conjunctival redness (grade 1) was noted in one animal at hour 1 after application only. The two other animals showed obvious conjunctival redness (grade 2) at hour 1, which decreased to slight conjunctival redness (grade 1) from hour 24 until hour 48. Slight conjunctival chemosis (grade 1) was seen in two animals at hour 1, while obvious or severe discharge (grade 2 or 3) was noted in all animals 1 hour after application.
Injected scleral vessels in a circumscribed area were noted in all animals at hour 1 after application.

Interpretation of results:

GHS criteria not met

Conclusions:

Considering the described ocular reactions as well as the average score for irritation, the test item does not show an eye irritating potential under the test conditions chosen.

Executive summary:

The potential of the test item to cause damage to the conjunctiva, iris or cornea was assessed by a single ocular application of 0.1 mL of the undiluted test item to one eye of three New Zealand White rabbits (stepwise procedure starting with one animal and supplementing two additional animals). About, but not less than, 24 hours after application the eye was rinsed with tap water. The ocular reactions were assessed approximately 1, 24, 48 and 72 hours after application. Additional eye examinations were performed 24 and 48 h after application with the instillation of a fluorescein solution. Due to absence of detectable lesions following fluorescein instillation, all subsequent readings were performed without the aid of fluorescein. Neither corneal nor iris lesions were noted in all animals at any examination time point. Even after instillation of a fluorescein solution no corneal lesions were detectable after 24 and 48 hours. The following test item-related clinical observations were recorded during the course of the study: Slight to obvious conjunctival redness (grade 1 to 2), slight conjunctival chemosis (grade 1), obvious to severe discharge (grade 2 to 3), injected scleral vessels in a circumscribed area were noted in the animals at hour 1 after application only. The ocular reactions were reversible in one animal within 24 hours and in two animals within 72 hours after application. Mean scores calculated for each animal over 24, 48 and 72 hours were 0.0, 0.0 and 0.0 for corneal opacity and for iris lesions, 0.0, 0.7 and 0.7 for redness of the conjunctiva and 0.0, 0.0 and 0.0 for chemosis, respectively. Considering the described ocular reactions as well as the average score for irritation, the test item does not show an eye irritating potential under the test conditions chosen.

Reference 2

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 20th, 1989 to June 27th, 1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

(1987)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Kleintierfarm Madoerin AG, CH-4414 Fuellinsdorf
- Age at study initiation: approximately 12-14 weeks
- Weight at study initiation: 2500 to 2700 g
- Housing: individually in metal cages (and identified by individually numbered ear tags)
- Diet: standard rabbit pellet (Nafag No. 814, Gossau, Switzerland) ad libitum
- Water: fresh water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 +/- 3°C
- Humidity (%): 30-70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12h / 12h

All batches of the diet are assayed for nutritive ingredients and contaminant level by the manufacturer.
The drinking water quality fulfilled the critical parameters in the specification of the "Schweizerisches Lebensmittelbuch" (Edition 1972).

Vehicle:

unchanged (no vehicle)

Controls:

other: the untreated eye served for control

Amount / concentration applied:

0.1 mL was instilled into the conjunctival sac of the left eye of each animal. The right eye served as untreated control.

Duration of treatment / exposure:

0.1 mL was instilled into the conjunctival sac of the left eye of each animal, the lids were then held together for about one second in order to prevent loss of the test item. The treated eyes were not rinsed.

Observation period (in vivo):

72 hours, extended to 7 days because reactions were observed within 72 hours after instillation of the test item.

Number of animals or in vitro replicates:

3 female rabbits

Details on study design:

The ocular reactions were evaluated 1, 24, 48, and 72 hours after the instillation according to the OECD scoring system. A slit-lamp was used to facilitate the evaluation. Because reactions were observed within 72 hours after treatment, the observation period was extended to 7 days to determine the reversibility of the eye reactions.
Moreover, the animals were checked daily for systemic symptoms and mortality.

Irritation parameter:

cornea opacity score

Remarks:

(mean)

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

other: Corneal opacity was seen in none of the 3 animals

Irritation parameter:

iris score

Remarks:

(mean)

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

other: Effect in the iris graded 1 was seen in 1/3 animals at reading time point 1 hour only.

Irritation parameter:

conjunctivae score

Remarks:

(mean)

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.33

Max. score:

1

Reversibility:

fully reversible within: 48 h

Remarks on result:

other: Conjunctival redness graded 1 was seen at reading time points 1 and 24 hrs but no more thereafter.

Irritation parameter:

conjunctivae score

Remarks:

(mean)

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.66

Max. score:

1

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: Conjunctival redness graded 1 was seen at reading time points 1, 24 and 48 hours, and no more thereafter.

Irritation parameter:

conjunctivae score

Remarks:

(mean)

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.66

Max. score:

1

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: Conjunctival redness graded 1 was seen at reading time points 1, 24 and 48 hours, and no more thereafter.

Irritation parameter:

chemosis score

Remarks:

(mean)

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

other: Chemosis graded 1 was seen in each of the 3 animals at reading time point 1 h only.

Irritant / corrosive response data:

Under the experimental conditions employed, iritis, conjunctival redness and chemosis, all of them graded 1, were reported for all 3 animals at reading time point 1 hour; no corneal opacity was seen. Almost all findings disappeared within 24 to 48 hours, and complete reversibility was achieved at reading time point 72 hours.

Other effects:

None

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions employed the test article induced minimal irritation of the iris and conjunctiva well below the threshold of significance when instilled into the conjunctival sac of albino rabbits.

Executive summary:

The substance was instilled into the conjunctival sac of one eye in each of 3 female rabbits according to the OECD TG 405; the eyes were not rinsed. The treatment induced iritis, conjunctival redness and chemosis, all of them graded 1, in each of the 3 animals at reading time point 1 hour; no corneal opacity was seen. Almost all findings disappeared within 24 to 48 hours, and complete reversibility was achieved at reading time point 72 hours. Based on the scoring of the eye findings as recommended by the OECD guideline, the test item was not irritating to the eye of rabbit.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

The potential of the test item to cause acute dermal irritation or corrosivity was assessed by a single topical application of an amount of 0.5 mL of the test item for 4 hours to the intact skin of three New Zealand White rabbits (stepwise procedure starting with one animal, supplementing two additional animals), using a patch of 2.5 cm x 2.5 cm, covered with semi-occlusive dressing. After removal of the patch the application area was washed off. The cutaneous reactions were assessed immediately after removal of the patch, approximately 1, 24, 48 and 72 hours after removal of the patch and at weekly intervals until study day 14 at the latest. Very slight or well-defined erythema (grade 1 or 2) was noted in two animals immediately after removal the patch. At hour 1, very slight erythema was observed in all animals and persisted until hour 24, 48 or 72 after application, respectively. In one of these animals very slight erythema progressed to well-defined erythema on day 7. The cutaneous reactions were reversible in two animals within 3 days and in one animal within 14 days after removal of the patch. Mean scores over 24, 48 and 72 hours for each animal were 0.3, 1.0 and 0.7 for erythema and 0.0, 0.0 and 0.0 for edema, respectively Considering the described cutaneous reactions as well as the average score for irritation, XPDL 920 does not show a skin irritating potential under the test conditions chosen.

Eye irritation

The potential of the test item to cause damage to the conjunctiva, iris or cornea was assessed by a single ocular application of 0.1 mL of the undiluted test item to one eye of three New Zealand White rabbits (stepwise procedure starting with one animal and supplementing two additional animals). About, but not less than, 24 hours after application the eye was rinsed with tap water. The ocular reactions were assessed approximately 1, 24, 48 and 72 hours after application. Additional eye examinations were performed 24 and 48 h after application with the instillation of a fluorescein solution. Neither corneal nor iris lesions were noted in all animals at any examination time point. Even after instillation of a fluorescein solution no corneal lesions were detectable after 24 and 48 hours. Slight conjunctival redness (grade 1) was noted in one animal at hour 1 after application only. The two other animals showed obvious conjunctival redness (grade 2) at hour 1, which decreased to slight conjunctival redness (grade 1) from hour 24 until hour 48. Slight conjunctival chemosis (grade 1) was seen in two animals at hour 1, while obvious or severe discharge (grade 2 or 3) was noted in all animals 1 hour after application. Injected scleral vessels in a circumscribed area were noted in all animals at hour 1 after application. The ocular reactions were reversible in one animal within 24 hours and in two animals within 72 hours after application. Mean scores calculated for each animal over 24, 48 and 72 hours were 0.0, 0.0 and 0.0 for corneal opacity and for iris lesions, 0.0, 0.7 and 0.7 for redness of the conjunctiva and 0.0, 0.0 and 0.0 for chemosis, respectively. Considering the described ocular reactions as well as the average score for irritation, the test item does not show an eye irritating potential under the test conditions chosen.

Assessment of structural analogue substance (EC 406-040-9)

Skin irritation

Two skin irritation studies are available, both showing the same result of transient erythema. Low grade Edema scores were observed only at the one hour reading in a single animal. In the key study erythema graded 1 was seen in all 3 animals at reading time point 1 hour and persisted until 24 hours in only one case. After 48 hours, recovery was complete (Ciba-Geigy, 1989). In the supporting study, erythema was seen in 2/3 animals at reading time point 1 hour and was graded 1 and 2, respectively. Erythema graded 2 persisted until 24 hours. At reading time point 48 hours, erythema had completely disappeared (Ciba-Geigy, 1987).

Eye irritation

Two studies are avaliable assessing the ocular irritation potential of the test article. In the key study, the substance was instilled into the conjunctival sac of one eye in each of 3 female rabbits according to the OECD TG 405; the eyes were not rinsed (Ciba-Geigy, 1989). The treatment induced iritis, conjunctival redness and chemosis, all of them graded 1, in each of the 3 animals at reading time point 1 hour; no corneal opacity was seen. Almost all findings disappeared within 24 to 48 hours, and complete reversibility was achieved at reading time point 72 hours. The study was performed under GLP.

In the supporting study, the substance was instilled into the conjunctival sac of one eye in each of 3 female rabbits according to the OECD TG 405; the eyes were not rinsed (Ciba-Geigy, 1987). Conjunctival redness and chemosis graded 1-2 were reported for all 3 animals at reading time point 1 hour; neither corneal opacity nor effects in the iris was seen. Complete reversibility was achieved at reading time point 72 hours.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data for a structural analogue substance are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for skin or eye irritation under Regulation (EC) No 1272/2008, as amended for the eighth timeRegulation (EU) No 2016/218.