2-methylcyclopentane-1,3-dione

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

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)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-methylcyclopentane-1,3-dione

EC Number:

212-153-2

EC Name:

2-methylcyclopentane-1,3-dione

Cas Number:

765-69-5

Molecular formula:

C6H8O2

IUPAC Name:

2-methylcyclopentane-1,3-dione

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Test item: Methyl-cyclopentanedioneCAS No.: 765-69-5Batch No.: S39129NPhysical state: solid, crystalline powderColour: beigeStorage: at a temperature of 15 to 30 °C

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Species and strain: CBA/Ca Ola Hsd miceSource: TOXI-COOP ZRT.Hygienic level at arrival: SPFHygienic level during the study: Good conventionalNumber of animals: 24 animals/main test (4 animals/treatment group)Sex: Female, nulliparous, non-pregnantAge of animals: Young adult mice; 10-11 weeks old (at start of the main test)Body weight range at starting: 17.6-22.2 gAcclimatization time: 7 daysAnimal health: Only healthy animals were usedHousing during acclimatization period: Grouped caging in small groupsHousing during the test: Grouped caging (4 animals/cage)Light: 12 hours daily, from 6.00 a.m. to 6.00 p.m.Temperature: 22 ± 3 °CRelative humidity: 30 – 70 %

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Remarks:

AOO (acetone:olive oil, 4:1) for positive control groups

Concentration:

The test item was administered at three different concentrations (5; 2,5; 1 w/v%) according to the results of the dose range finding test.

No. of animals per dose:

4 animal/dose

Details on study design:

Selection of test item concentrations was based on the results of a formulation evaluation and also results of preliminary irritation/toxicity test to find an appropriate solvent and the maximum applicable concentration according to the relevant guidelines [1-2]. Based on the preliminary test results the test item was examined in the main test at 5 %, 2.5 % and 1 % (w/v) concentrations as formulations in the selected vehicle of N,N-Dimethylformamide (DMF). Appropriate positive control (α-Hexylcinnamaldehyde [HCA] in 25 % (w/v) concentration), furthermore two negative control groups dosed with the vehicles of the test and positive control groups, respectively, were employed.The positive control item (25 % (w/v) HCA in Acetone: Olive oil 4:1 (v/v) mixture, AOO) induced the appropriate stimulation over the control, thus confirming the validity of the assay.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

The stimulation index (SI = the DPN of a treated (positive control or test item) group divided by the DPN of the respective negative control group) for each treatment group was also calculated. A stimulation index of 3 or greater is an indication of a positive result. When monotonic dose-response is seen, attempt is made to calculate EC3 (dose calculated to induce a stimulation index of 3) with the help of linear regression on dose-response relationship. All calculations were made by Microsoft Excel Software. (See Table1 for the values.)

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

DPM (disintegration per minute) was measured for each treatment group. The measured DPM values were corrected with the background DPM value. The average of the two measured DPM values of 5 % (w/v) TCA solutions was used as the background DPM value. The results were expressed as DPN (DPM divided by the number of pooled lymph nodes). (See Table1 for the values.)

Results 3

Parameter:

SI

Value:

0.5

Remarks on result:

other: Methyl-cyclopentanedione 5 % in DMF

Results 4

Parameter:

SI

Value:

0.6

Remarks on result:

other: Methy-cyclopentanedione 2.5 % in DMF

Results 5

Parameter:

SI

Value:

0.5

Remarks on result:

other: Methyl-cyclopentanedione 1 % in DMF

Any other information on results incl. tables

Test Group Name	Measured DPM/group	Group* DPM	DPN (DPM/Node)	Stimulation Index Values
Vehicle control for the positive control: AOO	7283	7258.0	907.3	1.0
Positive control: 25 % HCA in AOO	93261	93236.0	11654.5	12.8
Methyl-cyclopentanedione 5 % in DMF	2857	2832.0	354.0	0.5
Methy-cyclopentanedione 2.5 % in DMF	3069	3044.0	380.5	0.6
Methyl-cyclopentanedione 1 % in DMF	2956	2931.0	366.4	0.5
Vehicle control for the test item: DMF	5397	5372.0	671.5	1.0

 *Group DPM = measured DPMgroup- average DPMbackground

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information

Conclusions:

In conclusion, under the conditions of the present Local Lymph Node Assay, Methyl-cyclopentanedione (CAS No. 765-69-5) tested at the maximum attainable concentration of 5 % (based on solubility) and at concentrations of 2.5 % and 1 % (w/v) as formulations in an appropriate vehicle (DMF) was shown to have no skin sensitization potential.