Titanium diboride

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

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:

Titanium diboride

EC Number:

234-961-4

EC Name:

Titanium diboride

Cas Number:

12045-63-5

Molecular formula:

B2Ti

IUPAC Name:

titanium diboride

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Titanium Diboride TiB2 – 45 µm Batch No 703M1 test item sponsored by the lead registrant ESK Ceramics GmbH & Co. KG, Purity see chapter 1.4

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Species/strain: healthy rats, WISTAR rats Crl: WI(Han) (full barrier)

Source: Charles River, 97633 Sulzfeld, Germany

Sex: male and female; The female animals were non-pregnant and nulliparous.

Number of animals: 5 male and 5 female

Age at the beginning of the study: males: 9 weeks old, females: 16 weeks old

Body weight on the day of administration: males: 245 – 253 g; females: 213 – 227 g.

The 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 [9] the animals were bred for experimental purposes.

Housing and Feeding Conditions

- Full barrier in an air-conditioned room
- Temperature: 22 +- 3 °C
- Relative humidity: 55 +- 10%
- 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. 0715)
- Free access to tap water, sulphur acidified to a pH value of approximately 2.8 (drinking water, municipal residue control, microbiological controls at regular intervals)
- The animals were kept individually in IVC cages, type III H, polysulphone cages on Altromin saw fibre bedding (lot no. 261111)
- Certificates of food, water and bedding are filed at BSL BIOSERVICE
- Adequate acclimatisation period (at least five days) under laboratory conditions

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

Application
The test item was applied at a single dose, uniformly over an area which was approximately 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.


Exposure Period
The test item was held in contact with the skin throughout a 24-hour period. At the end of the exposure period the residual test item was removed using aqua ad injectionem (see Vehicle)
.

Vehicle
Aqua ad injectionem (Diprom, lot no. 10952-1, expiry date: 09/2013)

Duration of exposure:

24 h

Doses:

The 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 male and 5 female

Control animals:

not required

Details on study design:

Observation Period
The surviving animals /All animals were observed for 14 days after dosing.

Primary Skin Irritation
Signs of erythema and oedema were assessed using the scoring system laid down in OECD Guideline 404.

Weight Assessment
The animals were weighed on day 1 (prior to the application) and on days 8 and 15.

Clinical Examination
A 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.

Pathology
At the end of the observation period the surviving animals were sacrificed with an overdosage of pentobarbital injected intraperitoneally (Narcoren®, Merial; lot no. 218121; expiry date: 12/2014) at the dosage of approximately 8 mL/kg bw.
All animals were subjected to gross necropsy. All gross pathological changes were recorded and in case of findings the tissues were preserved for a possible histopathological evaluation. The preserved tissues of which no histopathological evaluation was made will be discarded 3 months after the release of the final report unless otherwise agreed upon with the sponsor.

Evaluation of Results
Individual 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 a tabular form.
Necropsy findings were described.

Statistics:

Not applicable, no clinical signs of irritation or mortality.

Results and discussion

Preliminary study:

not applicable

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

no deaths

Clinical signs:

other: other: no signs of systemic toxicity, dermal irritation,

Gross pathology:

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

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the present study, single dermal application of the test item Titanium Diboride to rats up to 2000 mg/kg body weight was associated with no mortality and neither signs of toxicity nor signs of irritation.

The dermal LD50 was determined to be > 2000 mg Titanium Diboride / kg body weight.

In conformity with the criteria given in Annex VI to Commission Directive 2001/59/EC [6] the test item Titanium Diboride has no obligatory labelling requirement for percutaneous toxicity.

According to Annex I of Regulation (EC) 1272/2008 [7] the test item Titanium Diboride has no obligatory labelling requirement for percutaneous toxicity and is unclassified.

According to GHS (Globally Harmonized Classification System) [8] the test item Titanium Diboride has no obligatory labelling requirement for percutaneous toxicity and is not classified.

Executive summary:

On the basis of the test results given below and in conformity with the criteria given in Annex VI to Commission Directive 2001/59/EC, the substance should be not classified.

On the basis of the test results given below and in conformity with the criteria given in Annex I of Regulation (EC) 1272/2008, the substance should be not classified.

On the basis of the test results given below and in conformity with the criteria given in GHS (Globally Harmonized System of Classification and Labelling of Chemicals), the substance should be not classified.

LD₅₀:             > 2000 mg/kg bw

Species/strain:                                         WISTAR Crl: WI(Han) rats

Vehicle (moistening):                               aqua ad injectionem

Number of animals:                                  5 male and 5 female

Duration of exposure:                             24 hours

Method:                                                  OECD 402; EC 440/2008, Method B.3; OPPTS 870.1200

 

Table1:  Results per Step

Sex	Dose (mg/kg bw)	Number of Animals	Number of Intercurrent Deaths
male	2000	5	0
female	2000	5	0

Signs of toxicity related to dose level used, time of onset and duration:

No treatment-related effects were observed.

Effect on organs (related to dose level):

No treatment-related effects were observed.

Signs of irritation:

No erythema or oedema was observed.