reaction mass of dipentarythritol and 3-mercaptopropionic acid

Skin sensitisation

Administrative data

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)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Dept. of Health, UK

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

(2-hydroxyethyl)ammonium mercaptoacetate

EC Number:

204-815-4

EC Name:

(2-hydroxyethyl)ammonium mercaptoacetate

Cas Number:

126-97-6

Molecular formula:

C2H7NO.C2H4O2S

IUPAC Name:

2-hydroxyethanaminium sulfanylacetate

Constituent 2

Reference substance name:

MEATG

IUPAC Name:

MEATG

Test material form:

solid - liquid: suspension

Details on test material:

- Batch No. 5156
- Content: 83.5% MEATG in water

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Study design: in vivo (LLNA)

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)

Results and discussion

Positive control results:

Hexylcinnamaldehyde was shown to be a skin sensitiser, confirming the validity of the protocol used for the study.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

12.6

Test group / Remarks:

linear interpolation between 10 and 25%

Results 2

Parameter:

SI

Value:

0.93

Test group / Remarks:

5%

Results 3

Parameter:

SI

Value:

2.39

Test group / Remarks:

10%

Results 4

Parameter:

SI

Value:

5.89

Test group / Remarks:

25%

Any other information on results incl. tables

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.

Applicant's summary and conclusion

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%