Graphite

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-01-22 to 2010-03-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well performed GLP study according to OECD technical 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)

Remarks:

Certificate is attached to the full study report.

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

1

Reference substance name:

Graphite

EC Number:

231-955-3

EC Name:

Graphite

Cas Number:

7782-42-5

Molecular formula:

C

IUPAC Name:

carbon

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Strain Wistar Crl:(WI)WU
- Age at study initiation: 5 weeks at delivery
- Weight at study initiation: 149g - 160g
- Housing: Makrolon, type III cages, two rats of the same sex and dose group per cage; cages and absorbing softwood bedding material were changed twice a week or more often if necessary
- Diet (e.g. ad libitum): Ssniff V1534, Ssniff Spezialdiäten, Soest, Germany, ad libitum
- Water (e.g. ad libitum): Tap water from Hannover city water supplier, ad libitum
- Acclimation period: 2-3 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 2°C
- Humidity (%): 55% +/- 15%
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

- Expanded Graphite Powder was formulated in water (appropriate vehicle), resulting in a concentration of 200 mg/ml (slightly pasty suspension).
- 2 ml per 200 g b.w. of the animals of this formulation was administered by gavage to the rats amounting to a dose of 2000 mg/kg b.w. (exact volumes were calculated on the day of administration based on actual body weights).
- For the administration an oral flexible polymeric cannula was used.
- The night before administration and for 4 hours after treatment rats were fasted (food only; water ad libitum)

Doses:

2000mg/kg body weight

No. of animals per sex per dose:

6 (tested subsequently in groups of 3 rats each)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

DAILY AND WEEKLY OBSERVATIONS
- all animals were observed in their cages daily
- once a week they were carefully examined for abnormalities
- on the day of treatment all animals were observed several times for clinical symptoms
- thereafter, the frequency of observation was once a day (or more often if necessary) for the following 14 days
- clinical observation especially comprised: general condition, fur, grooming activity, visible mucous membranes, behavior and locomotor activity, central nervous symptoms, breathing pattern

BODY WEIGHTS
- at least once a week individual body weights were recorded to the nearest 0.1g for all animals
- in addition the animals were weighed on the morning before being treated

BODY TEMPERATURE BEFORE START AND AFTER END OF EXPOSURE
- was measured rectally to the nearest 0.1°C before and twice after treatment (1 and 4hrs)

REFLEXES UPON CESSATION OF EXPOSURE
- Grooming activity as detectable by fur condition, mobility, ataxia, visual placing, climbing reflex, pinna reflex, vibrissae reflex, auditory startly, pain sensitivity and seizures were investigated 1, 24 and 48hrs after treatment
- all parameters were assessed using a standardised scheme as influenced or not influenced (normal)

GROSS PATHOLOGY/NECROPSY
- all animals were carefully necropsied, comprising examination of the external surface, all orifices and the cranial, thoraic and abdominal cavities and their contents

Statistics:

- differences in rectal temperature before and after treatment of groups were considered case by case as statistically significant at the level p<0.05.
- t-test was used.

Results and discussion

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

No mortalities.

Clinical signs:

other: - No signs of discomfort or toxicity effects

Gross pathology:

- None of the rats showed any abnormalities upon necroscopy 14 days after the treatment

Other findings:

BODY TEMPERATURE
- See Table 2
- No abnormalities were observed

REFLEXES
- Reflexes did not show abnormalities 1, 24 or 48hrs after treatment of rats

Any other information on results incl. tables

Summary table of results

Limit test with Expanded Graphite Powder
	Treatment Group
Number of treated rats	6
Number of rats showing affected reflexes	0 / 0 / 0 1/24/48 hrs after treatment
Mean of body temperature (SD) 4 hrs after treatment	37.5 °C (0.6 °C)
Number of dead animals within 14-day post-observation period	0
Rats showing abnormalities in gross pathology on day 14 of post-observation period	0

Terminal body weights

Wistar WU, females	Terminal body weights (g) day 14 (individual data)	Terminal body weights (g) day 14 (means with standard deviation)
1201	198.6	204.2+5.3 (n=3) February 8, 2010
1202	204.8
1203	209.1
1204	192.7	193.4+1.4 (n=3) February 10, 2010
1205	195.0
1206	192.5

Applicant's summary and conclusion

Conclusions:

From the results observed in this acute oral toxicity study the following classification was derived for test item Expanded Graphite Powder: Unclassified (according to Regulation (EC) No 1272/2008).

Executive summary:

-      Six female Wistar rats received a single oral gavage dose of the test item Expanded Graphite Powder suspended in water, and administered at a dose of 2000 mg/kg body weight.

-      None of the animals showed any clinical signs of reaction to treatment.

-      All animals showed a continuous increase of body weights throughout the study period.

-      All six animals were killed as scheduled at study termination (after a 14-day observation period).

-      The animals did not show any abnormalities upon macroscopic examination.

-      From the results observed in this acute oral toxicity study the following classification was derived for test item Expanded Graphite Powder: Unclassified (according to Regulation (EC) No 1272/2008).

-      An LD₅₀was not determined in this study. An experimentally determined LD₅₀ is estimated to be > 2000 mg/kg body weight.