2-methylpropyl-(R)-2-hydroxypropanoate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Publication. Meets national standard methods. Lactic acid used as read-across partner.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Compilation of historical local lymph node data for evaluation of skin sensitization alternative methods

Author:

Gerberick GF, Ryan CA, Kern PS, Schlatter H, Dearman RJ, Kimber I, Patlewicz GY and Basketter DA

Year:

2005

Bibliographic source:

Dermatitis 16(4): 157-202

Reference 2

Reference Type:

publication

Title:

Strategies for identifying false positive responses in predictive skin sensitization tests

Author:

Basketter DA, Gerberick GF and KImber I

Year:

1998

Bibliographic source:

Food Chem Toxicol 36: 327-33

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

not specified

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Lactic acid

EC Number:

200-018-0

EC Name:

Lactic acid

Cas Number:

50-21-5

IUPAC Name:

2-hydroxypropanoic acid

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): Lactic acid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

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

Study design: in vivo (LLNA)

Vehicle:

dimethyl sulphoxide

Concentration:

5.0, 10.0 and 25 %

No. of animals per dose:

No data

Details on study design:

Groups of CBA female mice were exposed topically on the dorsum of both ears to 25 µL of test material or to an equal volume of the relevant vehicle. Treatment was performed daily for 3 consecutive days. Five days after the initiation of exposure, all mice were injected via the tail vein with 250 µL of phosphate-buffered saline containing 20 µCi of tritated thymidine. The mice were sacrificed 5 hours later, and the draining auricular lymph nodes were excised and pooled for each experimental group or each individual animal. The incorporation of tritiated thymidine measured by beta scintillation counting was reported in disintegrations per minute. A stimulation index (SI) was calculated for each chemical-treated group as the ratio of the disintegrations per minute in the treated group (or mean disintegrations per minute when individual animals were assessed) to the disintegrations per minute or mean disintegrations per minute of the concurrent vehicle control group.

Positive control substance(s):

not specified

Statistics:

No data

Results and discussion

Positive control results:

No data

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: Dose group 5 %: 1.0 Dose group 10 %: 1.4 Dose group 25 %: 2.2

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: No data

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In a local lymph node assay in mice, lactic acid was tested negative for skin sensitisation.

Executive summary:

In a dermal sensitisation test according to OECD 429 female CBA mice were treated with concentrations of 5, 10 and 25 % lactic acid in DMSO. Stimulation indices of 1.0 (test group 5 %), 1.4 (test group 10 %) and 2.2 (test group 25 %) were measured. As the maximum stimulation index was < 3, lactic acid can be considered as not skin sensitising. This result is used in a read-across approach for the assessment of isobutyl-R-lactate.