Isopropyl acetoacetate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study is judged with reliability 1 even if not all information can be provided in the RSS. This is due to a two paged summary of the study provided by the study owner that did not contain all information needed to complete the RSS but a statement that the study is reliable without restrictions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

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:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Isopropyl acetoacetate

EC Number:

208-798-4

EC Name:

Isopropyl acetoacetate

Cas Number:

542-08-5

Molecular formula:

C7H12O3

IUPAC Name:

propan-2-yl 3-oxobutanoate

Test material form:

liquid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA/Ca

Remarks:

CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

Information not provided in LoA data.

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

12.5, 25, 50, 100 %

No. of animals per dose:

4

Details on study design:

PRE-SCREEN TESTS:
For determination of the highest non-irritant and technically applicable test item concentration, a non-GLP pretest was performed on two mice with concentrations of 6.25, 12.5, 25, 50, and 100 % (w/v).

MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentrations resulted in 3-fold or greater increase in incorporation of 3HTdR compared to the concurrent control, as indicated by the stimulation index. The estimated concentration of test item required to produce an S.I. of 3 is referred to as the EC3 value.

TREATMENT PREPARATION AND ADMINISTRATION:
Four female mice were treated with different concentrations of the test item and vehicle alone by topical application at the dorsum of each ear lobe (left and right) on three consecutive days. Five days after the first topical application, the mice were intravenously injected into a tail vein with radio-labelled thymidine (3H-methyl thymidine). Five hours after intravenous injection, the mice were sacrificed and the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of 3H-methyl thymidine measured in a beta-scintillation counter.

Positive control substance(s):

not specified

Results and discussion

Positive control results:

Information not provided in LoA data.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

0.36

Test group / Remarks:

100 %

Results 2

Parameter:

SI

Value:

0.48

Test group / Remarks:

50 %

Results 3

Parameter:

SI

Value:

0.76

Test group / Remarks:

25 %

Results 4

Parameter:

SI

Value:

1.62

Test group / Remarks:

12.5 %

Cellular proliferation data / Observations:

DETAILS ON STIMULATION INDEX CALCULATION :
The proliferative response of lymph node cells is expressed as the number of radioactive disintegrations per minute per lymph node and as the ratio of 3HTdR incorporated into lymph node cells of test lymph nodes relative to that recorded for control lymph nodes (stimulation index).
In this study stimulation indices of 1.62, 0.76, 0.48, and 0.36 were determined with the test item at concentrations of 12.5, 25, 50, and 100 % (w/v) in vehicle, respectively.

EC3 CALCULATION :
In this study the EC3 value could not be calculated, since none of the tested concentrations induced an S.I. greater than 3.

CLINICAL OBSERVATIONS:
No deaths occurred during the study period. No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period.

BODY WEIGHTS:
The body weights of the animals, recorded prior to the 1st application and prior to necropsy was within the range commonly recorded for animals of this strain and age.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item was determined to have no skin sensitising potential.

Executive summary:

Four female mice were treated with the test item at concentrations of 12.5, 25, 50 and 10 % (w/v) in a study according to OECD guideline 429. The test item was applied on the ears of the animals on three consecutive days. Five days after the first topical application, the mice were intravenously injected into a tail vein with radio-labelled thymidine (³H-methyl thymidine). Five hours after intravenous injection, the mice were sacrificed and the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of3H-methyl thymidine measured in a β-scintillation counter. No deaths occurred, no symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period. The body weights of the animals were within the range commonly recorded for animals of this strain and age. Stimulation indices of 1.62, 0.76, 0.48, and 0.36 were determined with the test item at concentrations of 12.5, 25, 50, and 100 % (w/v) in vehicle, respectively. Therefore, the test item was found to be not a skin sensitiser.