(2,3-dichlorophenyl)oxoacetonitrile

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:

other: Well documented study according to international accepted guidelines and GLP compliant.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

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:

(2,3-dichlorophenyl)oxoacetonitrile

EC Number:

278-747-9

EC Name:

(2,3-dichlorophenyl)oxoacetonitrile

Cas Number:

77668-42-9

Molecular formula:

C8H3Cl2NO

IUPAC Name:

2,3-dichlorobenzoyl cyanide

Test material form:

solid: crystalline

Details on test material:

Test item: 2,3-DICHLOROBENZOYL NITRILE
CAS No.: 77668-42-9
Batch No.: L36020N
Physical state: Yellow, crystalline powder
Colour: Light-yellow
Purity (GC): 96.48% (based on 2,3-DICHLOROBENZOYL NITRILE content)
Storage 15-30°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 mice
Source: TOXI-COOP ZRT.
Hygienic level at arrival: SPF
Hygienic level during the study: Good conventional
Number of animals: 28 animals/main test (4 animals/treatment group)
Sex: Female, nulliparous, non pregnant
Age of animals: Young adult mice; 10-11 weeks old (at start of the main test)
Body weight range at starting: 15.7-21.7 g
Acclimatization time: 7 days
Animal health: Only healthy animals were used

Housing during acclimatization period: Grouped caging in small groups
Housing 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 °C
Relative 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 four different concentrations (2,5; 1; 0,5; 0,25 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 tests to find the best solvent and the maximum applicable concentration according to the relevant guidelines. Due to significant adverse effects (systemic toxicity and/or irritation) observed at high test concentrations “2,3-DICHLOROBENZOYL NITRILE” (CAS No. 77668-42-9) was examined in the main test at 2.5 %, 1 %, 0.5 % and 0.25 % (w/v) non-toxic, non-irritant concentrations as formulations in the selected vehicle of N,N-Dimethylformamide (DMF). Appropriate positive control (α-Hexylcinnamaldehyde [HCA] in 25 % 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 % 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

Positive control results:

The positive control group animals were treated with 25 % (w/v) HCA solution (dissolved in AOO) concurrent to the test item groups. No mortality, cutaneous reactions or signs of toxicity were observed in the positive control group.
Significant lymphoproliferative response (SI ≥ 3) was noted for HCA (SI = 10.4). The results of the positive control item demonstrated appropriate performance of the test in accordance with the relevant guidelines and confirmed validity of the assay.

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. Based on the results EC3 value (dose calculated to induce a stimulation index of 3) of the test item was calculated. Dose-response relationship was evaluated by linear regression. All calculations were made by Microsoft Excel Software. (See Table1 fo 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 fo the values.)

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	8955	8890.0	1111.3	1.0
Positive control: 25% HCA in AOO	92586	92521.0	11565.1	10.4
2,3-DICHLOROBENZOYL NITRILE 2,5% in DMF	77283	77218.0	9652.3	5.8
2,3-DICHLOROBENZOYL NITRILE 1% in DMF	29287	29222.0	3652.8	2.2
2,3-DICHLOROBENZOYL NITRILE 0,5 % in DMF	12180	12115.0	1514.4	0.9
2,3-DICHLOROBENZOYL NITRILE 0,25% in DMF	9858	9793.0	1224.1	0.7
Vehicle control :for the test item: DMF	13336	13271.0	1658.9	1.0

 *Group DPM = measured DPM(group)- average DPM(background)

Applicant's summary and conclusion

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Remarks:

Migrated information

Conclusions:

In conclusion, under the conditions of the present Local Lymph Node Assay, “2,3-DICHLOROBENZOYL NITRILE” (CAS No. 77668-42-9) tested at the maximum applicable (non-toxic, non-irritant) concentration of 2.5 % (w/v) and at concentrations of 1 %, 0.5 % and 0.25 % as formulations in an appropriate vehicle (DMF) was shown to have sensitization potential.
Based on the EC3 value calculated using the dose-response curve “2,3-DICHLOROBENZOYL NITRILE” (CAS No. 77668-42-9) was classified as a moderate sensitizer in this LLNA according to the published data.