Silicon boride oxide

Endpoint summary

Description of key information

LD50 oral >2000 mg/kg bw
LD50 dermal >5000 mg/kg bw
LC50 inhalation >5.5 mg/L

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February - May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Qualifier:

according to guideline

Guideline:

other: Japan MAFF 8147

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

Young adult animals of comparable weight were used.
Acclimatization period of at least 5 days before the beginning of the experimental phase; during the acclimatization period, the animals were accustomed to the environmental conditions of the study and to the diet.
Individual animal identification by cage cards and tail marking.
The animals were housed in fully air-conditioned rooms. Central air-conditioning guaranteed a range of 22°C ± 3°C for temperature and of 30 – 70% for relative humidity. The day/night rhythm was 12 h light and 12 h darkness.
Single housing in Makrolon cages (type III).
Feeding: VRF1(P); SDS Special Diets Services, 67122 Altrip, Germany
Drinking water: Tap water ad libitum
Feed was withdrawn from the animals at least 16 hours before administration, but water was available ad libitum.

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Details on oral exposure:

0.5% solution of CMC in deionized water
A good homogeneity in water could not be guaranteed, because the test item preparation is a suspension. Therefore a 0.5% solution of CMC in deionized water was applicable.
The test item preparation was produced for each application group shortly before application by stirring with a high speed homogenizer (Ultra-Turrax) and a magnetic stirrer. Additionally the homogeneity of the test item preparation during application was ensured by stirring with a magnetic stirrer.
Form of application: Suspension
Concentration used: 20 g/100 ml
Administration volume: 10 ml/kg

Doses:

2000 mg/kg b.w. (2 test groups)

No. of animals per sex per dose:

2 test groups of 3 rats

Control animals:

no

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

None

Clinical signs:

other: No abnormalities

Gross pathology:

There were no macroscopic pathological findings at the end of the observation period.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September - October 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Qualifier:

according to guideline

Guideline:

other: Japan MAFF 8147

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age at exposure: 9 weeks
Body weight range at exposure: males: 240.6 to 258.1 g; females: 163.8 to 189.1 g
Housing conditions: Optimal hygienic conditions (OHC) inside a barrier system. Air-conditioned with 10 - 15 air changes per hour, continuously monitored environment with a temperature range of 22 ± 3°C, a relative humidity range of 30 - 70% and a 12 hour fluorescent light / 12 hour dark cycle.
The animals were housed in groups of 5 of the same sex in Makrolon type-IV cages with wire mesh tops and standard softwood bedding including paper enrichment.
Animals had ad libitum access to a pelleted standard Harlan Teklad 2914C rat maintenance diet, except during the period when the animals were restrained in exposure tubes. Community tap water from Füllinsdorf was available ad libitum in water bottles, except during the period when they were restrained in exposure tubes.

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5.5 mg/l

No. of animals per sex per dose:

5

Control animals:

no

Statistics:

No statistical analysis was performed as only one group was allocated to the study.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.5 mg/L air

Remarks on result:

other: gravimetrically determined mean aerosol concentration.

Mortality:

All animals survived the scheduled observation period.

Clinical signs:

other: Ruffled fur was recorded in all animals from the end of exposure until test day 3. Labored breathing was seen in two males starting during the last hour of exposure and lasting up to test day 2. There were no clinical signs from test day 4 of the observat

Body weight:

From test day 1 to test day 2, slight to marked body weight loss was noted in all males and four females. Stagnation of body weight was observed in the remaining female during this period. Thereafter normal body weight development was recorded in these animals.

Gross pathology:

There were no macroscopic findings.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 500 mg/m³ air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February - May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Qualifier:

according to guideline

Guideline:

other: Japan MAFF 8147

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Young adult animals of a comparable weight were used.
Acclimatization period of at least 5 days before the beginning of the experimental phase
The animals were housed in fully air-conditioned rooms with temperature of 22°C ± 3°C and relative humidity of 30 – 70%.
Air changes per hour: approx. 10
Day / night rhythm: 12 h / 12 h (6.00 a.m. – 6.00 p.m. / 6.00 p.m. – 6.00 a.m.)
Type of cage: Makrolon cage, type III
Number of animals per cage: single housing
Feeding: VRF1(P); SDS Special Diets Services, 67122 Altrip, Germany
Drinking water: Tap water ad libitum

Type of coverage:

semiocclusive

Vehicle:

CMC (carboxymethyl cellulose)

Duration of exposure:

24 hours

Doses:

5000 mg/kg

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

Observation period: 14 days
Individual body weight determination shortly before administration (day 0), weekly thereafter and on the last day of observation.
Recording of clinical signs several times on the day of administration, and at least once daily thereafter each workday for the individual animals.
A check for any dead or moribund animals was made at least once each workday, these records are archived by Bioassay.
Necropsy with gross-pathology examination on the last day of the observation period after sacrifice with CO2 in a chamber with increasing concentrations over time.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Mortality:

None

Clinical signs:

other: No signs of systemic toxicity or local effects were observed.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Additional information

Justification for selection of acute toxicity – oral endpoint
Guideline- and GLP study

Justification for selection of acute toxicity – inhalation endpoint
Guideline- and GLP study

Justification for selection of acute toxicity – dermal endpoint
Guideline- and GLP study

Justification for classification or non-classification

Based on the data available, silicon boride oxide does not fulfill the criteria for classification according to EC 1272/2008 (CLP). Therefore, non-classification is warranted.