boron nitride (hexagonal)

Endpoint summary

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:

1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

GLP conform study following US regulation for the enforcement of the "Federal Hazardous Substances Act 16 CFR 1500". Reports are not as detailed as modern protocols but include all required information. The principles and methodology used for testing is comparable to modern OECD 404 guideline besides longer exposure time compared to OECD 404 which is no considered critical regarding reliability of the study. Interpretation of the results is different to OECD 404 protocols and frequency of observation is lower. This is not considered critical regarding reliability of the study as results are reported in a way that interpretation according to the OECD 406 guideline was possible and 3 of four animals did not show any response after 72h. Therefore, the study is considered to be reliable.

Qualifier:

according to guideline

Guideline:

other: US regulation for the Enforcement of the Federal Hazardous Substances Act (16 CFR 1500)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

longer exposure time, less frequent observations

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Clerco Research Farm
- Age at study initiation: young adult
- Housing: single, suspension cages with wire mesh floors
- Diet (e.g. ad libitum): purina laboratory rabbit chow
- Water (e.g. ad libitum): ad libitum
- Acclimation period: min 1 day

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12 hrs. light/12 hrs. dark

Type of coverage:

occlusive

Preparation of test site:

other: shaved and intact

Vehicle:

physiological saline

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g
VEHICLE
- Amount(s) applied (volume or weight with unit): Test material moistened with 0.5 ml physiol. saline

Duration of treatment / exposure:

24 h

Observation period:

72 h

Number of animals:

6 (3 male and 3 female)

Details on study design:

TEST SITE
- Area of exposure: 1" x 1" gauze square

SCORING SYSTEM:
Application sites are scored for each rabbit immediately after removal of test material (24 h) and after 72 hours. The scoring system used is the following:
Erythema and Eschar Formation (mostseverely affected area graded):
No erythema: 0
Very slight erythema (barely perceptible): 1
Well defined erythema: 2
Moderate to severe erythema: 3
Severe erythema (beet redness) to slight eschar formation (injuries in depth): 4
Edema Formation (most severely affected area graded):
No edema: 0
Very slight edema (barely perceptible): 1
Slight edema (edges of area well-defined by defnite raising): 2
Moderate (raised approximately 1mm): 3
Severe edema (raised more than 1 mm and extending beyond area of exposure): 4

The values for each rabbit were totaled and averaged for each of the categories:
1 Erythema and eschar formation, intact skin, 24h
2 Erythema and eschar formation, abraded skin, 24h
3 Erythema and eschar formation, intact skin, 72h
4 Erythema and eschar formation, abraded skin, 72h
5 Edema, abraded skin 24 h
6 Edema, intact skin 24 h
7 Edema, abraded skin 72 h
8 Edema, intact skin 72 h

The eight average scores are added and the results divided by four to obtain the Primary Irritation Index. A corrosive material is a material which causes destructive or irreversible damage to tissue. A primary irritant is one which gives a PII of five or more.

Irritation parameter:

erythema score

Basis:

mean

Time point:

48 h

Remarks on result:

not measured/tested

Irritation parameter:

edema score

Basis:

mean

Time point:

48 h

Remarks on result:

not measured/tested

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Score:

1.9

Max. score:

8

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: No changes in coloration or texture of the skin were noted. No evidence of corrosion was found.

Irritation parameter:

erythema score

Basis:

mean

Time point:

24 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 72h

Irritation parameter:

edema score

Basis:

mean

Time point:

24 h

Score:

1.5

Max. score:

4

Reversibility:

fully reversible within: 72h

Irritation parameter:

erythema score

Basis:

mean

Time point:

72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

edema score

Basis:

mean

Time point:

72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Interpretation of results:

GHS criteria not met

Conclusions:

Application of hexagonal boron nitride for 24 h to intact and abraded skin did not result in damage to the skin. Slight edema observed directly after 24 h exposure was not existent 48 h after end of exposure (72 h). Hexagonal boron nitride does neither have to be classified as irritant nor as corrosive.

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:

1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP conform study which was performed following US regulation for the enforcement of the "Federal Hazardous Substances Act 16 CFR 1500". Study protocol is slightly different to actual OECD guideline 403. Reports are not as detailed as modern protocols but includes all necessary information. The principles and methodology used for testing is comparable to modern guidelines. Observation period was shorter than according to OECD 403 guideline and the dose was smaller. Evaluation of results (scoring system) identical to OECD 403 guideline. The shorter observation period is not considered critical regarding reliability of the study as 5 of six animals did not show any symptoms 48 h after application. Therefore, the study is considered to be reliable.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

shorter observation period, dose smaller than recommended in OECD guideline

Qualifier:

according to guideline

Guideline:

other: US regulation for the Enforcement of the Federal Hazardous Substances Act (16 CFR 1500)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Clerko Research Farm
- Age at study initiation: young adult
- Housing: housed singly in suspension cages with wire mesh floors
- Diet (e.g. ad libitum): purina laboratory rabbit chow
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: min 1 day

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12 hrs light/12 hrs dark

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.048 g to one eye of each animal

Duration of treatment / exposure:

48 h (eyes were not rinsed)

Observation period (in vivo):

48 h (observations 1h, 24h and 48h after start of exposure)

Number of animals or in vitro replicates:

6

Details on study design:

Test substance was applied to one eye, the other served as control.
SCORING SYSTEM: identical to OECD 403 guideline
Observation according to the method of Draize (1959)

Irritation parameter:

chemosis score

Basis:

animal #6

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #5

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #4

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #6

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #5

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #4

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #6

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #5

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #4

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #6

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #5

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #4

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

overall irritation score

Basis:

animal #1

Time point:

other: 1h

Score:

2

Max. score:

110

Reversibility:

fully reversible within: 24 h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #1

Time point:

other: 24h

Score:

0

Max. score:

110

Reversibility:

fully reversible

Irritation parameter:

overall irritation score

Basis:

animal #2

Time point:

other: 1h

Score:

4

Max. score:

110

Reversibility:

fully reversible within: 48h

Remarks on result:

other: Only conjunctival redness grade 2 was observed

Irritation parameter:

overall irritation score

Basis:

animal #2

Time point:

other: 24h

Score:

2

Max. score:

110

Reversibility:

fully reversible within: 48h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #2

Time point:

other: 48h

Score:

0

Max. score:

110

Reversibility:

fully reversible

Irritation parameter:

overall irritation score

Basis:

animal #3

Time point:

other: 1h

Score:

2

Max. score:

110

Reversibility:

not fully reversible within: 48h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #3

Time point:

other: 24h

Score:

2

Max. score:

110

Reversibility:

not fully reversible within: 48h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #3

Time point:

other: 48h

Score:

2

Max. score:

110

Reversibility:

not fully reversible within: 48h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #4

Time point:

other: 1h

Score:

2

Max. score:

110

Reversibility:

fully reversible within: 24h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #4

Time point:

other: 24h

Score:

0

Max. score:

110

Reversibility:

not fully reversible within: 24h

Irritation parameter:

overall irritation score

Basis:

animal #5

Time point:

other: 1h

Score:

2

Max. score:

110

Reversibility:

fully reversible within: 24h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #5

Time point:

other: 24h

Score:

0

Max. score:

110

Reversibility:

fully reversible within: 24h

Irritation parameter:

overall irritation score

Basis:

animal #6

Time point:

other: 1h

Score:

2

Max. score:

110

Reversibility:

fully reversible within: 24h

Remarks on result:

other: Only conjunctival redness grade 1 was observed

Irritation parameter:

overall irritation score

Basis:

animal #6

Time point:

other: 24h

Score:

0

Max. score:

110

Reversibility:

fully reversible within: 24h

Interpretation of results:

GHS criteria not met

Conclusions:

When hexagonal boron nitride was applied to the eyes of New Zealand white rabbits, 1h after instillation, all animals showed conjunctivae redness grade 1 (5 of 6 animals) or grade 2 (one animal). 24 h after exposure, 3 of 6 animals still showed conjunctivae redness grade 1 and 48 h after exposure in only one animal conjunctivae redness grade 1 was observed. No other responses (of coroneal opacy or iris or conjunctival redness) have been observed during the observation period (48h after the test material has been applied to the eye) and no evidence of corrosion was noted. Against this background, the short observation period is not considered critical as 48 h after application 5 of six animals showed no symptoms. The reduced dose (0.048 g instead of 0.1 g) is also not considered critical regarding reliability of the study as all effects observed (conjunctival redness) most likely result from the physical properties of the substance and application of the twofold dose is assumed not to cause different or severe effects. Hexagonal boron nitride is therefore not classified as an irritant by occular application and does not have to be classified as corrosive to the eye.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available