Registration Dossier

Administrative data

Description of key information

MeaTG 83% is a moderate skin sensitiser (Skin Sens 1B) with an EC3 of 12.6%

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2003-09-29 - 2003-12-16
Reliability:
1 (reliable without restriction)
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Dept. of Health, UK
Type of study:
mouse local lymphnode assay (LLNA)
Test material information:
Composition 1
Species:
mouse
Strain:
CBA
Sex:
female
Vehicle:
propylene glycol
Concentration:
The test substance was initially applied as 0.25%, 0.5% or 1.0% w/v preparation in propylene glycol. Further groups of animals were subsequently doses with 2.5%, 5%, 10%, 10% or 25% w/v preparations in propylene glycol.
No. of animals per dose:
4
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Positive control results:
Hexylcinnamaldehyde was shown to be a skin sensitiser, confirming the validity of the protocol used for the study.
Key result
Parameter:
EC3
Value:
12.6
Test group / Remarks:
linear interpolation between 10 and 25%
Parameter:
SI
Value:
0.93
Test group / Remarks:
5%
Parameter:
SI
Value:
2.39
Test group / Remarks:
10%
Parameter:
SI
Value:
5.89
Test group / Remarks:
25%

A sample of MeaTG 83% was assessed for its skin sensitisation potential using the mouse Local Lymph Node Assay. The assay determines the level of T lymphocyte proliferation in the lymph nodes draining the site of chemical application, by measuring the amount of radiolabelled thymidine incorporated into the dividing cells.

Concentration of test substance (% w/v)

Number of lymph nodes assayed

Disintegrations per minute (dpm)

dpm per lymph node

Test control ratio

0 (vehicle only)

8

1910

2.39

 N/A

0.25

8

3111

3.89

1.63

0.5

8

1648

2.06

0.86

1.0

8

2261

2.83

1.18

0 (vehicle only)

8

4362

5.45

N/A

2.5

8

4865

6.08

1.12

5

8

4039

5.05

0.93

10

8

2315

2.89

0.53

0 (vehicle only)

8

4468

5.59

 N/A

10

8

10676

13.35

2.39

25

8

26317

32.90

5.89

N/A: not applicable

The test substance was shown to have the capacity to cause skin sensitisation when applied as a 25% w/v preparation in propylene glycol. In conclusion, MeaTG 83% is a skin sensitiser.

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
MeaTG 83% is a moderate skin sensitiser with an EC3 of 12.6%
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

Experiences in humans confirmed the sensitizing potential of thioglycolates in general.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on sufficient animal and human data TGA and its salts can be classified as:

DSD: R43. May cause sensitisation by skin contact.

EU-GHS: Skin Sens. 1B. H317. May cause an allergic skin reaction.