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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
other: Literature data
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
publication
Title:
Acute Toxicological Effects of Multi-Walled Carbon Nanotubes (MWCNT)
Author:
Murthy et al.
Year:
2011
Bibliographic source:
Carbon Nanotubes - Growth and Applications, Dr. Mohammad Naraghi (Ed.), InTech, DOI: 10.5772/18984

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
OECD Guidelines for Testing of Chemicals, Number 406 "Skin Sensitization", adopted by the Council on July 17,1992 (reported Paris, April 29,1993).
Deviations:
no
GLP compliance:
not specified
Type of study:
Buehler test
Justification for non-LLNA method:
no details given

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: nanomaterial
Details on test material:
MWCNT1: 5-8 microns in length with 3-8nm inside diameter and outside diameter of 140±30 nm; Product No. 659258, purchased from Sigma-Aldrich, USA.
Specific details on test material used for the study:
MWCNT1: 5-8 microns in length with 3-8 nm inside diameter and outside diameter of 140 ± 30 nm; Product No. 659258 purchased from Sigma-Aldrich, USA.
The multi-walled carbon nanotubes used in the study were produced by catalytic chemical vapor deposition (CCVD). MWCNT1 were composed of 99.9 % carbon with small amount (<0.1% Fe) of iron. The manufacturer specification for nanomaterial characterization was confirmed by the following techniques. MWCNT1 characteristics were assessed in the as-synthesized form prior to use for experiments or after dispersion in the vehicle (distilled water) for dosing. Solution characteristics were measured with dynamic light scattering (DLS).

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 300 - 400 g
- Housing: individually in standard stainless steel cages and sterilized paddy husk as bedding. Bedding material was changed daily, whereas water bottles were changed on alternate days
- Diet (e.g. ad libitum): ad libitum standard rabbit pellet food (supplier: M/s. Amrut Laboratory Animal Feed, Pune). The diet was supplemented with ascorbic acid.
- Water (e.g. ad libitum): ad libitum supply of UV treated water
The food and water was routinely analyzed and are considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3 °C
- Humidity (%): 50 ±20 %
- Photoperiod (hrs dark / hrs light): 12 h light/dark cycle

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
not specified
Remarks:
purified
Concentration / amount:
400 mg
Day(s)/duration:
induction (day 1), same treatment was repeated on day 7 and 14
Adequacy of induction:
not specified
Challenge
Route:
epicutaneous, occlusive
Vehicle:
not specified
Concentration / amount:
200 mg
Day(s)/duration:
challenge on day 28, observation 30 and 54 h after challenge exposure
Adequacy of challenge:
not specified
No. of animals per dose:
20 (test group)
10 (control group)
Details on study design:
- Exposure period: day 0, day 7, day 14
- Test groups: 20 animals
- Control group: 10 animals
- Site: One flank of each animal was closely clipped free of hair, without any abrasion, 24 hours before the induction exposure
- Frequency of applications: 3 times
- Duration: 6h
- Concentrations: 400 mg

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: day 28
- Test groups: 20 animals
- Control group: 10 animals
- Site: posterior flank of both treatment and control groups
- Concentrations: 200 mg
- Evaluation (hr after challenge): 30h and 54 h after application challenge
Positive control substance(s):
not specified

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
30
Group:
test group
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
None of the animals treated with MWCNT1 showed any dermal reactions
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
54
Group:
test group
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
None of the animals treated with MWCNT1 showed any dermal reactions
Remarks on result:
no indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
None of the animals treated with MWCNT1 exhibited any dermal reactions. Hence MWCNT1 could be considered as non sensitizer.
Executive summary:

In order to assess the cutaneous allergenic potential of MWCNT1, the Buehler-Test was performed in 30 (20 test and 10 control) male Dunkin Hartley guinea pigs, in accordance with OECD Guideline No. 406 and the Directive 96/54/EEC, B.6.

The test substance at a dose of 400 mg was applied to all the animals of treatment group for a period of 6 h. The same treatment was repeated on days 7 and 14. Similarly, the animals in control group were treated with distilled water. On day 28 the nanomaterial was applied on a cotton pad at a dose of 200 mg to both treatment and control groups for 6 h.

The skin reactions were observed and scored at 30 h and 54 h after application.

None of the animals treated with MWCNT1 did exhibited any dermal reactions. Hence MWCNT1 could be considered as non sensitizer.