Sodium pyruvate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

publication

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)

Version / remarks:

2002

Deviations:

no

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Methyl pyruvate

EC Number:

209-987-4

EC Name:

Methyl pyruvate

Cas Number:

600-22-6

Molecular formula:

C4H6O3

IUPAC Name:

methyl 2-oxopropanoate

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 7-12 weeks

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

1, 2.5, 5 and 10%

No. of animals per dose:

4

Details on study design:

ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: A substance was classified as a skin sensitizer, if, at one or more test concentrations, it induced a 3-fold or greater increase in LNC proliferative activity compared with concurrent vehicle-treated controls.

TREATMENT PREPARATION AND ADMINISTRATION: Mice were treated topically on the dorsum of both ears with 25 µL of test material or with an equal volume of the vehicle (AOO) alone. Treatment was performed daily for 3 consecutive days.

Results and discussion

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

2.4

Results 2

Parameter:

SI

Value:

1.2

Test group / Remarks:

concentration: 1 %

Results 3

Parameter:

SI

Value:

2.3

Test group / Remarks:

concentration: 2.5 %

Results 4

Parameter:

SI

Value:

4.7

Test group / Remarks:

concentration: 5 %

Results 5

Parameter:

SI

Value:

8

Test group / Remarks:

concentration: 10 %

Cellular proliferation data / Observations:

EC3 CALCULATION
The EC3 value was calculated by interpolating between 2 points on the SI axis, one immediately above and one immediately below the SI value of 3. The vehicle-treated control value (by definition, SI = 1) cannot be used for the latter. Where the data points lying immediately above and below the SI value of 3 have the co-ordinates (a, b) and (c, d), respectively, then the EC3 value may be calculated using the equation: EC3 = C + [3 - d/b - d](a - c)

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

The test item was determined to have a skin sensitising potential (GHS Category 1B).

Executive summary:

A local lymph node assay was performed according to OECD guideline 429 to assess the skin sensitising potential of the test item. The test was performed with four CBA mice per dose group. As vehicle acetone/olive oil (4:1) was used. The mice were treated topically in the dorsum with 25 µL of the test item (1, 2.5, 5 or 10 %.) or the vehicle alone. Treatment was performed daily for 3 consecutive days. 5 days following the initiation of exposure, all mice were injected via the tail vein with 250 µL of phosphate-buffered saline (PBS) containing 20 µCi of tritiated thymidine. Mice were sacrificed 5h later, and the draining lymph nodes excised and pooled for each experimental group. The determined stimulation indices were 1.2 (1 %), 2.3 (2.5 %), 4.7 (5 %) and 8.0 (10 %) and the determined EC3 value was 2.4. Therefore, the test item was determined to have a skin sensitising potential (GHS Category 1B).