Hexanoic acid, 2-ethyl-, zinc salt, basic

Endpoint summary

Description of key information

Skin irritation: irritating (OECD 404, GLP)

Eye irritation: irritating (OECD 405; GLP)

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:

1996-11-20 to 1996-12-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

1992-07-17

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Broekman Institute, Someren, The Netherlands
- Age at study initiation: approx. 7 weeks
- Weight at study initiation: 1290 - 1555 g
- Housing: individually in labelled cages with perforated floors (Scanbur Denmark and equipped with an automatic drinking system (ITL, Bergen, The Netherlands)
- Diet: Standard laboratory rabbit diet (LKK-20, pellet diameter 4 mm, Hope Farms, Woerden,The Netherlands approx. 100 g/day; hay (BMI, Helmond, the Netherlands) was provided once a week
- Water (ad libitum): tap-water diluted with decalcified water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 21°C
- Relative humidity: 50%
- Air changes: approx. 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL of the undiluted test substance was applied to the skin

Duration of treatment / exposure:

4 hours

Observation period:

approximately 1, 24, 48 and 72 hours and 7, 14 and 21 days after the removal of the dressings and test substance

Number of animals:

3 male rabbits

Details on study design:

A health inspection was performed prior to the commencement of treatment, to ensure that the animals were in a good state of health. Special attention was paid to the skin to be treated, which was intact and free from abnormalities.
TEST SITE
- Area of exposure: approximately 24 hours before treatment, the dorsal fur was clipped with electric clippers, exposing an area of approximately 150 square centimeters (10 x 15 cm^2).
On test day 1 the test substance was applied to the skin of one flank, using a surgical gauze patch of 2 X 3 cm. The patch was mounted on Micropore tape (Supplier, 3M, St. Paul, U.S.A.) which was wrapped around the abdomen and secured with Coban elastic bandage (Supplier, 3M, St. Paul, U.S.A.).


REMOVAL OF TEST SUBSTANCE
- Washing: the dressing was removed and the remaining test substance removed using a tissue moistened with tap-water and subsequently a dry tissue.
- Time after start of exposure: four hours after the application

Whenever considered necessary the treated skin areas were re-clipped at least 3 hours before the observations, to facilitate the scoring.

SCORING SYSTEM: according to the Draize scale
The irritation scores and a description of all other (local) effects were recorded. Adjacent areas of the untreated skin of each animal served as controls.

OBSERVATIONS
- Mortality/Viability: twice daily
- Toxicity: at least once daily
- Body weight: day of treatment (prior to application)

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 21 days

Remarks on result:

other: Thick layer of scales was observed on day 7; Bald skin was observed on day 14

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: day 21

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2.33

Max. score:

4

Reversibility:

fully reversible within: day 21

Remarks on result:

other: Yellow discolouration of the skin in 40% of the treated area was observed 72 hours after test item administration and on day 7; Thick layer of scales was observed on day 7 and bald skin on day 14.

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: day 21

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: day 14

Remarks on result:

other: Yellow discolouration of the skin and a thick layer of scales were observed on day 7 and bald skin on day 14.

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: day 21

Irritant / corrosive response data:

Four hours exposure to the test substance resulted in well-defined or moderate to severe erythema and slight or moderate oedema in the treated skin areas of the three rabbits. Yellow discolouration of the skin was noted in two animals 72 hours and/or 7 days after exposure. A thick layer of scale was observed after 7 days and bald skin after 14 days in all animals.
The skin irritation had resolved within 21 days after exposure in all animals.
There was no evidence of a corrosive effect on the skin.
Greasy remnants of the test substance were present on the skin of all animals on day 1. Also, very slight erythema (grade 1) was observed in two animals 1 hour after exposure. Well-defined erythema was observed in the third animal 1 hour after exposure.

Other effects:

No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Interpretation of results:

irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

According to the EC-Commission directive 67/548/EEC and its subsequent amendments, the test substance is irritating to the skin.
According to the EC Regulation No. 1272/2008 and subsequent regulations, the substance is not classified.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-11-25 to 1996-12-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

1987-02-24

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Broekman Institue, Someren, The Netherlands
- Age at study initiation: approx. 7 weeks
- Weight at study initiation: 1289 - 1599 g
- Housing: individually in cages with perforated floors (Scanbur Denmark) and equipped with an automatic drinking system (ITL, Bergen, The Netherlands).
- Diet: standard laboratory rabbit diet (LKK-20, pellet diameter 4 mm, Hope Farms, Woerden, The Netherlands); approx. 100 g/day and hay (BMI, Helmond, The Netherlands) was provided once a week
- Water (ad libitum): tap-water diluted with decalcified water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 21°C
- Relative humidity: 50%
- Air changes: approx. 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL of the test substance was instilled in the conjunctival sac of one eye of each animal after gently pulling the lower lid away from the eyeball. The lids were then gently held together for about one second to prevent loss of the test substance. The other eye remained untreated and served as the reference control.

Duration of treatment / exposure:

not applicable

Observation period (in vivo):

approximately 1, 24, 48 and 72 hours and 7, 14 and 21 days after instillation of the test substance (Exception: eyes of one animal were also examined daily from 21 days up to 29 days after instillation)

Number of animals or in vitro replicates:

3 male rabbits

Details on study design:

A health inspection was performed prior to commencement of treatment, to ensure that the animals were in a good state of health. Special attention was paid to the eyes, which were free from any abnormality.

SCORING SYSTEM: according to the Draize scale

TOOL USED TO ASSESS SCORE:
Immediately after the 24 hour observation, a solution of 2% fluorescein in water (adjusted to pH 7.0) was instilled into both eyes of each animal to quantitatively determine corneal epithelial damage. When considered necessary, this procedure was repeated to assess recovery.

In case standard lighting was considered inadequate for observing minor effects, eye examinations were performed using an ophthalmic examination lamp.
In cases of equivocal results when comparing the treated and untreated eyes, the illustrated guide from Consumer Product Safety Commission, Washington, D.C. 20207 was used for additional control purposes.

OBSERVATIONS:
- Mortality/viability: twice daily
- Toxicity: at least once daily
- Body weight: day of treatment (prior to instillation).

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.67

Max. score:

4

Reversibility:

fully reversible within: 7 days

Remarks on result:

other: 24 h: no opacity; epithelial damage max. 25% of cornea; white covered eyelids / 48 h: white covered eyelids/ 72 h: epithelial damage max. 25% of cornea; reduced elasticity of eyelids / 7d: epithelial damage 10% of cornea; pannus; neovascularisation

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.33

Max. score:

2

Reversibility:

fully reversible within: 48 hours

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: 24 h: redness of nictitating membrane / 48 h & 72 h: redness of eyelids & sclera / 7 d: redness of sclera

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: 24, 48 & 72 h: chemosis of eyelids / 48 & 72 h: chemosis of nictitating membrane / 48 h, 72 h & 7 d: chemosis of sclera

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: 24 h: white covered eyelids

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2.33

Max. score:

3

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: 24 h, 48 h, 72 h & 7d: redness of eyelids / 24 & 48 h: redness of nictitating membrane & sclera

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Remarks on result:

other: 24 h: chemosis of eyelids; 48 h: chemosis of nictitating membrane and sclera

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.67

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: 24 h: no opacity; epithelial damage max. 25% of cornea; white covered eyelids / 48 h: white covered eyelids / 72 h: epithelial damage max. 25% of cornea / 7 d: epithelial damage max. 25% of cornea; eye lids stuck together & released by soaking with water

Remarks on result:

other: 14 d: epithelial damage 10% of cornea; pannus, neovascularisation

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: 7 d grade 1 was observed, fully reversible on 14 d

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

fully reversible within: 21 days

Remarks on result:

other: 24 h, 48 h & 7 d: redness of eyelids / 48 h , 72 h, 7 d & 14 d: redness of sclera

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.33

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: 24 h, 48 h & 72 h: chemosis of eyelids, nictitating membrane and sclera

Irritant / corrosive response data:

Two animals showed corneal injury consisting of opacity (maximum grade 1-2) and epithelial damage (maximum 25% of the corneal area). As a result of the corneal injury pannus, neovascularisation of the cornea, was apparent 7 days after instillation in one animal and 14 days after instillation in the second animal. The corneal injury had resolved within 14 days in the first animal and within 21 days in the second animal. No cornel injury was observed in the third animal. Iridic irritation grade 1 was observed in one animal after 1 hour, in the second animal after 1 and 24 hours and in the third animal after 1 hour and 7 days. The irritation of the conjunctivae consisted of redness, chemosis and discharge and had completely resolved within 14 days in two animals and within 21 days in the third animal.
A white covering was observed on the eyelids of all animals 24 and/or 48 hours after instillation. Reduced elasticity of the eyelids was noted in one animal 72 hours after instillation. The eyelids of another animal were struck together, 7 days after instillation and were released by soaking with abundant water.
Unexpectedly, one animal, which was free of any ocular irritation after 14 days, showed signs of ocular irritation between 21 and 29 days after instillation. The irritation consisted of corneal injury (opacity, epithelial damage and pannus), iridic irritation and conjunctival irritation. Minimal discharge persisted after 29 days (termination of the study). This irritation, which showed a relative slow recovery, was considered not to be related to the test substance treatment but to have been caused by accident. The latter results were excluded from interpretation.
There was no evidence of ocular corrosion.
No staining of peri-ocular tissue by the test substance was observed.

Other effects:

No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Interpretation of results:

irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test material is irritating to the eye.
According to 67/548/EC and subsequent regulations, the test substance is classified as an eye irritant.
According to the EC Regulation No. 1272/2008 and subsequent regulations, the test substance is classified as Category 2.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation

One reliable in vivo study described by Pels Rijcken (1997) (OECD 404; GLP compliant) is considered to be reliable without restrictions.

Eye irritation

One reliable in vivo study described by Pels Rijcken (1997) (OECD 405; GLP compliant) is considered to be reliable without restrictions. The substance was determined to be irritating to the eyes.

Justification for selection of skin irritation / corrosion endpoint:

Key study.

Justification for selection of eye irritation endpoint:

Key study.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: irritating

Justification for classification or non-classification

Skin irritation

Reference Pels Rijcken (1997) is considered as the key study for in vivo skin irritation and will be used for classification. The skin irritation was scored according to the Draize scale. The mean score (24, 48, 72 h) for erythema and oedema for all three animals were as follows:

Erythema: 2, 2.33 and 2

Oedema: 1, 2 and 2

In addition, yellow discolouration of the skin was noted in two animals 72 hours and/or 7 days after exposure. A thick layer of scales was observed after 7 days and bald skin after 14 days in all animals. The skin irritation had resolved within 21 days after exposure in all animals.The study was terminated after 21 days. The test substance is not classified according toregulation (EC) 1272/2008 and subsequent amendments. The test substance has to be classified as skin irritant according to Directive 67/548 EC.

Eye irritation

Reference Pels Rijcken (1997) is considered as the key study for in vivo eye irritation and will be used for classification. The eye irritation was scored according to the Draize scale. The mean score (24, 48, 72 h) for cornea, iris conjunctivae redness and chemosis all three animals were as follows:

Cornea: 0.67, 0 and 0.67

Iris: 0.33, 0 and 0

Conjunctivae redness: 3, 2.33 and 3

Chemosis: 2, 1 and 1.33

The study was terminated after the 21 days.According to regulation (EC) 1272/2008 and subsequent amendments the substance will be classified as irritating to eyes (Category 2).