Boron

Endpoint summary

Description of key information

Skin irritation: not irritating (OECD 404 (1992); GLP compliant)

Eye irritation: not irritating (OECD 405 (1987); GLP compliant)

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:

2001-02-27 to 2001-03-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

adopted 1992-07-17

Deviations:

yes

Remarks:

deviation from the guideline occurred, with no effect on the results of the study: individual body weights of the animals were not given

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Ltd., Bicester, Oxon, England
- Age at study initiation: at least 12 weeks of age
- Weight at study initiation: 2.6 to 2.8 kg
- Housing: animals were housed individually in stainless steel cages with perforated floors.
- Diet (ad libitum): a standard laboratory rabbit diet (Special Diet Services STANRAB (P) SQC pellet); the animals were fed hay on arrival and subsequently three times a week.
- Water (ad libitum): drinking water
- Acclimation period: five days prior to start of study

During the acclimatisation and study period the animals were given small (approximately 5 cm x 2 cm x 2 cm) soft white untreated wood blocks for environmental enrichment.

ENVIRONMENTAL CONDITIONS
- Temperature: 19 ± 2°C
- Relative humidity: 30 to 70%
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): approximately 0.5 g of the test substance moistened with distilled water.

VEHICLE
- Amount(s) applied (volume or weight with unit): 0.5 mL distilled water

Duration of treatment / exposure:

4 hours

Observation period:

approximately 60 minutes after removal of the dressings and approximately 24, 48 and 72 hours after exposure

Number of animals:

3 male rabbits

Details on study design:

TEST SITE
- Area of exposure: approximately 24 hours prior to application of the test substance, hair was removed with electric clippers from the dorso-lumber region of each rabbit exposing an area of skin approximately 100 mm x 100 mm.
The test substance was applied under a 2-ply 25 mm x 25 mm porous gauze pad, which had been moistened with distilled water, to one intact skin site on each animal.
- Type of wrap: each treatment site was covered with "Elastoplast" elastic adhesive dressing for four hours. The animals were not restrained during the exposure period and were returned to their cages immediately after treatment.

REMOVAL OF TEST SUBSTANCE
- Washing: the dressing and gauze pad were removed and the treatment site was washed with warm water (37°C) to remove any residual test substance. The treated area was blotted dry with absorbant paper.
- Time after start of exposure: at the end of the exposure period

SCORING SYSTEM: according to the Draize scoring system
Any other reaction not covered by this scoring system was described.

OBSERVATIONS:
- Clinical sings: all animals were observed daily for signs of ill health or toxicity.

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: Brown residual test substance staining (assessment of erythema not impaired) was observed at the approximately 60 minutes and 24 hour observations.

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: Brown residual test substance staining (assessment of erythema not impaired) was observed at the approximately 60 minutes and 24 hour observations.

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: Brown residual test substance staining (assessment of erythema not impaired) was observed at the approximately 60 minutes and 24 hour observations.

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

No dermal irritation was observed following a single semi-occlusive application of boron amorphous to intact rabbit skin for four hours. Brown residual test substance staining (which did not impair assessment of erythema) was noted for all animals during the study.

Other effects:

- Clinical signs: there were no signs of toxicity or ill health in any rabbit during the observation period.

Interpretation of results:

not classified

Conclusions:

A single semi-occlusive application of boron amorphous to intact rabbit skin for four hours elicited no dermal irritation.
According to the EC-Commission directive 67/548/EEC and its subsequent amendments, the test substance is not classified as skin irritant.
According to the EC-Regulation 1272/2008 and subsequent regulations, the test item is not classified as skin 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:

experimental study

Adequacy of study:

key study

Study period:

2001-03-07 to 2001-03-11

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:

adopted 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: Highgate Farm, Market Rasen, Lincolnshire, England
- Age at study initiation: at least 10 weeks of age
- Weight at study initiation: 2.7 to 3.4 kg
- Housing: the animals were housed individually in metal cages with perforated floors.
- Diet (ad libitum): a standard laboratory rabbit diet (Special Diet Services STANRAB (P) SQC pellet); the animals were fed hay on arrival and subsequently three times a week.
- Water (ad libitum): drinking water
- Acclimation period: a minimum period of eight days prior to the start of the study

During the acclimatisation and study period the animals were given small (approximately 5 cm x 2 cm x 2 cm) soft white untreated wood blocks for environmental enrichment.

ENVIRONMENTAL CONDITIONS
- Temperature: 19 ± 2°C
- Relative humidity: 30 to 70%
- 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): A volume of 0.1 mL of the test substance (53 to 66 mg of the test material; mean weight 61 mg) was placed in the lower everted lid of one eye of each animal.
The eyelids were then gently held together for one second before releasing. The contralateral eye remained untreated.

Duration of treatment / exposure:

not applicable

Observation period (in vivo):

1 hour and approximately 24, 48 and 72 hours after instillation

Number of animals or in vitro replicates:

3 male rabbits

Details on study design:

The eyes of each animal were examined prior to instillation of the test substance to ensure that there was no pre-existing corneal damage, iridial inflammation or conjunctival irritation.

INITIAL AND CONFIRMATORY TESTS
One animal was treated in advance of the other two, to ensure that if a severe response was produced, no further animals would be exposed.

SCORING SYSTEM: according to the Draize scoring system


TOOL USED TO ASSESS SCORE:
Observation of the eyes was aided by the use of a handheld light.

OBSERVATIONS:
- Clinical signs: all animals were observed daily for signs of ill health or toxicity.

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

other: Conjunctival redness (grade 1) was observed at the 1 hour observation.

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

other: Conjunctival redness (grade 1) was observed at the 1 hour observation.

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

other: Conjunctival redness (grade 1) was observed at the 1 hour observation.

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

No corneal damage or iridial inflammation was observed.
Transient hyperaemia of the blood vessels of the conjunctivae was seen in all three animals, resolving completely by one day after instillation

Other effects:

- Clinical signs: there were no signs of toxicity or ill health in any rabbit during the observation period.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

A single instillation of boron amorphous into the eye of the rabbit elicited transient, very slight conjunctival irritation in all animals.
According to the EC-Commission directive 67/548/EEC and its subsequent amendments, the test substance is not classified as eye irritant.
According to the EC-Regulation 1272/2008 and subsequent regulations, the test item is not classified as eye irritant.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation

One reliable study described in Blanchard (2001)(OECD 404 (1992); GLP compliant) is considered to be reliable without restrictions and is used as key study for this endpoint. The substance was determined not to be a skin irritant.

Eye irritation

One reliable study described in Blanchard (2001)(OECD 405 (1987); GLP compliant) is considered to be reliable without restrictions and is used as key study for this endpoint. The substance was determined not to be an eye irritant.

Respiratory irritation

In an acute inhalation toxicity test (Coombs, 2001), there were no substance-specific treatment related effects, no macroscopic findings and no clinical observations that would indicate any respiratory irritation. Together with the complete absence of any irritation effects in skin and eye irritation tests performed with metallic boron and the assumed inertness based on its practically negligible water solubility, there is no reason to assume any respiratory irritation potential whatsoever for metallic boron.

Justification for selection of skin irritation / corrosion endpoint:

Key study

Justification for selection of eye irritation endpoint:

Key study

Justification for classification or non-classification

Skin irritation

Reference Blanchard (2001) will be used as key study for skin irritation and will be used for classification. The skin irritation was scored according to the Draize scale. The mean scores (24, 48, 72 h) for erythema and oedema for all three animals were as follows:

Erythema: 0 (all animals)

Oedema: 0 (all animals)

Brown residual test substance staining (assessment of erythema not impaired) was observed at the approximately 60 minutes and 24 hour observations. The study was terminated after approximately 72 hours. According to regulation (EC) 1272/2008 and subsequent amendments the substance will not be classified as skin irritant.

Eye irritation

Reference Blanchard (2001) will be used as key study for eye irritation and will be used for classification. The eye irritation was scored according to the Draize scale. The mean scores (24, 48, 72 h) for cornea, iris, conjunctival redness and chemosis for all three animals were as follows:

Cornea: 0 (all animals)

Iris: 0 (all animals)

Conjunctival redness: 0 (all animals)

Chemosis: 0 (all animals)

Conjunctival redness (grade 1) was observed in all animals at the 1 hour observation. According to regulation (EC) 1272/2008 and subsequent amendments the substance will not be classified as eye irritant.

Corrosive to the respiratory tract

There were no signs of respiratory irritation in an acute inhalation toxicity test (Coombs 2001) and also an absence of any irritation effects in skin and eye irritation tests. Hence classification as corrosive to the respiratory tract is not warranted.