Potassium mercaptoacetate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003-06-02 - 2003-10-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

Potassium mercaptoacetate

EC Number:

252-038-4

EC Name:

Potassium mercaptoacetate

Cas Number:

34452-51-2

Molecular formula:

C2H4O2S.K

IUPAC Name:

potassium sulfanylacetate

Constituent 2

Reference substance name:

KTG

IUPAC Name:

KTG

Test material form:

solid - liquid: suspension

Details on test material:

- Batch No. 5155
- Purity: 42.9%

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%,25% or 50% 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:

16.5

Test group / Remarks:

linear interpolation between 10% and 50%

Results 2

Parameter:

SI

Value:

1.58

Test group / Remarks:

10%

Results 3

Parameter:

SI

Value:

4.83

Test group / Remarks:

25%

Results 4

Parameter:

SI

Value:

12.04

Test group / Remarks:

50%

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

Based on an EC3 of 16.5%, KTG is a moderate skin sensitiser (Skin Sens 1B).

Executive summary:

A sample of KTG 43% 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	1896	2.37	N/A
0.25	8	4315	5.39	2.27
0.5	8	3675	4.59	1.94
1.0	8	2445	6.06	1.29
0 (vehicle only)	8	4362	5.45	N/A
2.5	8	4659	5.82	1.07
5	8	5443	6.80	1.25
10	8	6868	8.59	1.58
0 (vehicle only)	8	4468	5.59	N/A
25	8	21601	27.00	4.83
50	8	53827	67.28	12.04

N/A: not applicable

The test substance was shown to have the capacity to cause skin sensitisation when applied as a 30% w/v preparation in propylene glycol. In conclusion, KTG is a skin sensitiser.