Diamond

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2009 - February 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study generated according to international accepted testing guidelines.

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 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Diamond

EC Number:

231-953-2

EC Name:

Diamond

Cas Number:

7782-40-3

Molecular formula:

C

IUPAC Name:

carbon

Details on test material:

Name: Synthetic Diamond Grade 2 (2 micron) Powder
Physical State: solid
Density: 3.52 g/cm3
Purity: > 95 %

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

Test System
Species/strain: Healthy rats, WISTAR rats Crl: WI(Han) (Full-Banier)
Source: Charles River, 97633 Sulzfeld, Germany
Sex: female, non-pregnant, nulliparous
Number of animals: 3 per step
Age at the beginning of the study: 11 - 12 weeks old
Body weight at the beginning of the study:
Animals no. 1 - 3, step 1: 179 - 187 g;
Animals no. 4 - 6, step 2: 182 - 187 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 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 in groups 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, for details see Schedule)

Preparation of the Animals
The animals were marked for individual identification by tail painting.
Prior to the administration a detailed clinical observation was made of all animals.
Prior to the administration food was withheld from the test animals for 16 to 19 hours (access to water was permitted). Following the period of fasting the animals were weighed and the test item was administered. Food was provided again approximately 4 hours post dosing.

Gavage
The test item was administered at a single dose by gavage using a feeding tube.
The test item was administered at a dose volume of 5 ml/kg body weight.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

Aqua ad injectionem (sterile water, B. Braun Melsungen, lot no. 7949A191, expiry date: November 2010) This vehicle was chosen due to its non-toxic characteristics.

Details on oral exposure:

Dosage
The test item was administered at a single dose by gavage using a feeding tube.
The test item was administered at a dose volume of 5 ml/kg body weight.

Preparation of the Test ltem
In order to get the test item in a solution or suspension, which is applicable to the animals, several vehicles have been evaluated and preparation and solubility tests were performed.
The test item was weighed out into a tared plastic vial on a precision balance.
Homogeneity of the test item in the vehicle was maintained by vortexing the prepared suspension thoroughly before every dose administration.
For all animals of the first and second step, 2 g of the test item were dissolved in the vehicle to gain a final volume of 5 mL and to achieve a dose of 2000 mg/kg body weight at a dose volume of 5 mL/kg body weight.
The dose formulations were made shortly before each dosing occasion.

Vehicle
Aqua ad injectionem (B. Braun Melsungen, lot no. 7494AI9I, expiry date: November 2010)
This vehicle was chosen due to its minimal potential influence on irritation of the skin.

Doses:

Dose Level
The starting dose was selected to be 2000 mg/kg body weight. No compound related mortality was recorded for any animal of step 1 or 2. Based on these results and according to the acute toxic class method regime no further testing was required.

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

Observation Period
All animals were observed for 14 days after dosing for general clinical signs, morbidity and mortality.

Weight Assessment
The animals were weighed on day 1 (prior to the administration) 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. Particular attention was directed to observations of tremor, convulsions, salivation, diarrhoea, lethargy, sleep and coma.

Pathology
At the end of the observation period the animals were sacrificed with an overdosage of pentobarbital injected intraperitoneally Narcoren@, manufacturer: Material; lot no.: 193089; expiry date: August2012) at a dosage of approx. 8 mL/kg bw.
All animals were subjected to gross necropsy. All gross pathological changes were recorded.

Evaluation of Results
Results were interpreted according to OECD Guideline 423, Annex 2.
Individual reactions of each animal were recorded at each time of observation.
Toxic response data were recorded by dose level.
Nature, severity and duration of clinical observations were described.
Body weight changes were summarised in tabular form.
Necropsy findings were described.

Results and discussion

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

Under the conditions of the present study, single oral application of the test item Synthetic Diamond Grade 2 (2 micron) Powder to rats at a dose of 2000 mg/kg body weight was not associated with mortality.

Clinical signs:

other: The most relevant clinical findings in the animals treated with the test item at a dose of 2000 mg/kg bw were reduced spontaneous activity, slight dyspnoea, piloerection, apathy, half eyelid-closure, dark-red fundus oculi, closed eyes, prone position and

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:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

Under the conditions of the present study, single oral application of the test item Synthetic Diamond Grade 2 (2 micron) Powder to rats at a dose of 2000 mg/kg body weight was associated with slight signs of toxicity, but no mortality. The median lethal dose of Synthetic Diamond Grade 2 (2 micron) Powder after single oral administration to female rats, observed over a period of 14 days is:
LD56 cut off (rat): unclassified

In conformity with the criteria given in Annex VI to Commission Directive 2001/59/EC the test item Synthetic Diamond Grade 2 (2 micron) Powder has no obligatory labelling requirement for toxicity.

According to Annex I of Regulation (EC) 1272/2008 the test item Synthetic Diamond Grade 2 (2 micron) Powder was unclassified.

According to OECD-GHS (Globally Harmonised Classification System) the test item Synthetic Diamond Grade 2 (2 micron) Powder has no obligatory labelling requirement for toxicity.