boron nitride (cubic)

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2009 -January 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

boron nitride (cubic)

EC Number:

701-307-9

Cas Number:

10043-11-5

Molecular formula:

BN

IUPAC Name:

boron nitride (cubic)

Test material form:

solid: crystalline

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Test SystemSpecies/strain: Healthy rats, WISTAR Crl: WI(Han) (Full-Barrier)Source: Charles River, 97633 Sulzfeld, GermanySex: male and femaleThe female animals were nulliparous and non-pregnant.Body weight at the beginning of the study: females: 205 - 216 g, males 220 - 233 gAge at the beginning of the study: females: 13 weeks, males: 8 weeks oldNumber of animals: 5 male and 5 femaleThe animals were derived from a controlled full barrier maintained breeding system (SPF). According to Art. 9.2, No.7 of the German Act on Animal Welfare the animals were bred for experimental purposes.Housing and Feeding Conditions- Full-barrier in an air-conditioned room- Temperature: 22°C- Relative humidity: 55%- Artificial light, sequence being 12 hours light, 12 hours dark- Air change: 10 x / hour- Free access to Altromin 1324 maintenance diet for rats and mice (lot no. 1310)- Free access to tap water, sulphur acidified to a pH value of approx. 2.8 (drinking water, municipal residue control, microbiological control at regular intervals)- The animals were kept individually in IVC cages, type III H, polysulphone cages on Altromin saw fibre bedding (lot no. 060609)- Certificates of food, water and bedding are filed at BSL BIOSERVICE- Adequate acclimatisation period (at least five days)Preparation of the AnimalsThe animals were marked for individual identification by tail painting.Female animals: approximately 24 hours before the test, the fur was removed from the dorsal area of the trunk by using an electric clipperMale animals: approximately 25 hours before the test, the fur was removed from the dorsal area of the trunk by using an electric clipper. Care was taken to avoid abrading the skin, and only animals with healthy intact skin were used.No less than I0% of the body surface was cleared for the application.Prior to the application a detailed clinical observation was made of all animals.

Administration / exposure

Type of coverage:

occlusive

Vehicle:

water

Remarks:

Aqua ad injectionem (B. Braun Melsungen, lot no. 7494A191, expiry date: 11/2010) This vehicle was chosen due to its non-irritating characteristics.

Details on dermal exposure:

Preparation of the Test ltemThe test item was used as delivered by the sponsor.In order to ensure good skin contact, it was moistened with the vehicle.VehicleAqua ad injectionem (B. Braun Melsungen, lot no. 7494A191, expiry date: 11/2010)This vehicle was chosen due to its non-irritating characteristics.ApplicationThe test item was applied at a single dose, uniformly over an area which was approx. 10% of the total body surface.The test item was held in contact with the skin by a dressing throughout a 24-hour period. The dressing consisted of a gauze-dressing and non-irritating tape and was fixed with an additional dressing in a suitable manner.Observation PeriodAll animals were observed for 14 days after dosing.

Duration of exposure:

Exposure PeriodThe test item was held in contact with the skin throughout a 24-hov period. At the end of the exposure period residual test item was removed by using lukewarm tap water.

Doses:

Dose LevelThe test item was applied at a single dose of 2000 mg/kg body weight to each animal.

No. of animals per sex per dose:

5

Control animals:

not required

Details on study design:

Weight AssessmentThe animals were weighed on day 1 (prior to the application) and on days 8 and 15.Clinical ExaminationA careful clinical examination was made several times on the day of dosing (at least once during the first 30 minutes and with special attention given during the first 4 hours post-dose). As soon as symptoms were noticed they were recorded.Thereafter, the animals were observed for clinical signs once daily until the end of the observation period. All abnormalities were recorded.Cageside observations included changes in the skin and fur, eyes and mucous membranes. Also respiratory, circulatory, autonomic and central nervous systems and somatomotor activity and behaviour pattern were examined. Attention was directed to observations of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.PathologyAt the end of the observation period the animals were sacrificed with an overdosage of pentobarbital injected intraperitoneally Narcoren@, Merial; lot no.: 193089; expiry date:08/2012) at a dosage of approx. 8 mL/kg bw.All animals were subjected to gross necropsy. All gross pathological changes were recorded.Evaluation of ResultsIndividual reactions of each animal were recorded at each time of observation.Toxic response data were recorded by sex and dose level.Nature, severity and duration of clinical observations were described.The body weight changes were summarised in tabular form.Necropsy findings were described.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

The test item showed no acute dermal toxicity characteristics after a single dose application.

Clinical signs:

other: The test item showed no signs of dermal irritation and no acute dermal toxicity characteristics after a single dose application. Diarrhoea was observed in 1 of 5 male animals on day 2 and small scratches were observed in2 of 5 females and 1 of 5 male anim

Gross pathology:

With the exception of acute injection of blood vessels in the abdominal region, which is due to the euthanasia injection, no special gross pathological changes were recorded for any animal.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated informationCriteria used for interpretation of results: OECD GHS

Conclusions:

Under the conditions of the present study, the single dermal application of the test item Synthetic Cubic Boron Nitride Grade 2 (2 micron) Powder to rats at a dose of 2000 mg/kg body weight was associated neither with significant signs of skin irritation nor signs of toxicity or mortality.In conformity with the criteria given in Annex VI to Commission Directive 2001/59/EC the test item Synthetic Cubic Boron Nitride Grade 2 (2 micron) Powder has no obligatory labelling requirement for toxicity.The dermal LD50 was determined to be > 2000 mg Synthetic Cubic Boron Nitride Grade 2 (2 micron) Powder/kg body weight.According to Annex I of Regulation (EC) 1272/2008 the test item Synthetic Cubic Boron Nitride Grade 2 (2 micron) Powder does not requires classification for acute percutaneous toxicity since neither mortalities nor significant clinical signs of toxicity were observed at a dose of 2000 mg/kg body weight.According to OECD-GHS (Globally Harmonized Classification System) the test item Synthetic Cubic Boron Nitride Grade 2 (2 micron) Powder does not require classification for acute percutaneous toxicity since neither mortalities nor significant clinical signs of toxicity were observed at a dose of 2000 mg/kg body weight.