Activated Carbon - Low Density Skeleton

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 February 2010 - 10 March 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Performed under GLP. The study was assigned a Klimisch 2 rating due to the read-across purpose, in accordance with the ECHA Practical guide #6 on the reporting of read-across in IUCLID.

Justification for type of information:

The justification for read across is attached as a separate document to the "Toxicological information" summary

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 429 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Activated Carbon - High Density Skeleton

EC Number:

931-328-0

Molecular formula:

C

IUPAC Name:

Activated Carbon - High Density Skeleton

Details on test material:

- Name of test material (as cited in study report): Steam Activated Carbon
- Physical state: Solid
- Analytical purity: Confidential information
- Lot/batch No.: Confidential information
- Expiration date of the lot/batch: Confidential information
- Storage condition of test material: At room temperature, moisture protected

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories B.V., Postbus 6174, 5960 AD Horst, The Netherlands
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 19.0-22.8 g
- Housing: Individually, under standard laboratory conditions
- Diet (e.g. ad libitum): Ad libitum, pelleted standard diet
- Water (e.g. ad libitum): Ad libitum, tap water
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 25-65
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

0, 5, 10 and 25%

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: Highest concentration that can be technically used was 25% in propylene glycol
- Irritation: No severe irritant effects were tolerated choosing the test concentrations (time points: 1 hour and 24+/-4 hours after application, on day 7)

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response:
1. Exposure to at least one concentration of the test item resulted in an incorporation of 3HTdR at least 3-fold or greater than that recorded in control mice, as indicated by the stimulation index, and
2. Data are compatible with a conventional dose response, although allowance must be made (especially at high topical concentrations) for either local toxicity or immunological suppression

TREATMENT PREPARATION AND ADMINISTRATION:
Test item was placed into a volumetric flask on a tared balance and propylene glycol was quantitatively added. The different test item concentrations were prepared individually. Homogeneity of the test item in vehicle was maintained during treatment with stirring. The preparations were made freshly before each dosing occasion.
Application of test substance to the animal was performed according to guideline (proliferative capacity was determined by incorporation of 20.4 uCi 3H-methyl thymidine per mouse).

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Mean values and standard deviation were calculated for the body weights.

Results and discussion

Positive control results:

The positive control was found to induce sensitisation in the test system, which was clear but not excessive as required by the OECD guideline: a Stimulation Index (SI) of 1, 1.78, 2.54 and 4.88 at concentrations of 0%, 5%, 10% and 25% was calculated.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

1.43

Test group / Remarks:

5%

Results 2

Key result

Parameter:

SI

Value:

2.85

Test group / Remarks:

10%

Results 3

Key result

Parameter:

SI

Value:

2.38

Test group / Remarks:

25%

Results 4

Key result

Parameter:

EC3

Remarks on result:

other: An EC3 value could not be calculated or derived

Cellular proliferation data / Observations:

disintegrations per minute (DPM)
Control: 1292 dpm
5%: 1853 dpm
10%: 3685 dpm
25%: 3074 dpm

Any other information on results incl. tables

- No deaths were noted during study period

- No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period

- Body weight was within the range commonly recorded for animals of this stratin and age

- An EC3 value could not be calculated or derived for steam activated carbon

Applicant's summary and conclusion

Interpretation of results:

other: not classified

Remarks:

based on CLP criteria

Conclusions:

Under the conditions of this study, steam activated carbon did not induce sensitisation in the mouse. The highest SI calculated was 2.85, which is below the threshold of 3 for classification. Therefore, the test substance does not need to be classified for sensitisation based on the criteria outlined in Annex I of 1272/2008/EC .

Executive summary:

This Local Lymph Node Assay (OECD 429) was performed to determine the sensitising potential of steam activated carbon in mice. Test concentrations of 5%, 10% and 25% in propylene glycol were used (highest technically achievable concentration). As a positive control alpha-hexylcinnamicaldehyde was used. Proliferative capacity was determined by incorporation of 20.4 uCi 3H-methyl thymidine per mouse and subsequent liquid scintillation counting. Mortality, clinical signs and body weight were recorded.

No mortality or clinical signs were noted and body weights were within the range commonly recorded for the test animals.

The amount of disintegration per minute that were measured by liquid scintillation counting were (after correction for background counts): 1292, 1853, 3685 and 3074 for the concentrations of 0%, 5%, 10% and 25%, respectively. Accompanying Stimulation Indices (SI) that were calculated: 1.43, 2.85 and 2.38 for 5%, 10% and 25%, respectively.

Under the conditions of this study, steam activated carbon did not induce sensitisation in the mouse. The highest SI calculated was 2.85, which is below the threshold of 3 for classification. Therefore, the test substance does not need to be classified for sensitisation based on the criteria outlined in Annex I of 1272/2008/EC .