2,3-dichlorobenzaldehyde

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:

2015

Report date:

2015

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-dichlorobenzaldehyde

EC Number:

228-711-3

EC Name:

2,3-dichlorobenzaldehyde

Cas Number:

6334-18-5

Molecular formula:

C7H4Cl2O

IUPAC Name:

2,3-dichlorobenzaldehyde

Test material form:

solid: crystalline

Details on test material:

Test item: 2,3-dichlorobenzaldehydeCas No.: 6334-18-5Storage: 15-30 °C

In vivo test system

Test animals

Species:

mouse

Strain:

CBA/Ca

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 conventional.Number of animals: 28 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: 19.0-23.0 g The weight variation in animals involved in the study did not exceed ± 20 % of the mean weight.Acclimatization 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

Concentration:

Test item concentration: 0.5; 0.25; 0.1 ; 0.05 % w/v

No. of animals per dose:

4 animals/treatment group

Details on study design:

Animals in the treatment groups were treated with the relevant vehicles (DMF or AOO), appropriate formulations of the test item or 25 % concentration of the positive control substance. The test item was administered at four different concentrations according to the results of the dose range finding test.

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 = 5.0). 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:

EC3

Value:

0.09

Remarks on result:

other: based on the dose response curve

Results 2

Parameter:

EC3

Value:

0.11

Remarks on result:

other: based on the regression curve

Results 3

Parameter:

SI

Value:

3.9

Remarks on result:

other: 2,3 -dichloro-benzaldehyde 0.5% in DMF

Results 4

Parameter:

SI

Value:

3.6

Remarks on result:

other: 2,3-dichloro-benzaldehyde 0.25 % in DMF

Results 5

Parameter:

SI

Value:

3.1

Remarks on result:

other: 2,3-dichloro-benzaldehyde 0.1 % in DMF

Results 6

Parameter:

SI

Value:

2.6

Remarks on result:

other: 2,3-dichloro-benzaldehyde 0.05% in DMF

Any other information on results incl. tables

Test GroupName	Measured DPM/group	Group* DPM	DPN (DPM/Node)	Stimulation IndexValues
Vehicle control for the positive control: AOO	23412	23388.5	2923.6	1.0
Positive control: 25 % HCA in AOO	117447	117423.5	14677.9	5.0
2,3 -dichloro-benzaldehyde 0.5% in DMF	16534	16510.5	2063.8	3.9
2,3-dichloro-benzaldehyde 0.25 % in DMF	15018	14994.5	1874.3	3.6
2,3-dichloro-benzaldehyde 0.1 % in DMF	12904	12880.5	1610.1	3.1
2,3-dichloro-benzaldehyde 0.05% in DMF	10880	10856.5	1357.1	2.6
Vehiclecontrol for the test item: DMF	4231	4207.5	525.9	1.0

*Group DPM = measured DPMgroup- average DPMbackground

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

Under the conditions of the present Local Lymph Node Assay, 2,3-DICHLORO-BENZALDEHYDE (CAS No. 6334-18-5) tested at the maximum feasible (non-toxic, non-irritant) concentration of 0.5 % and at concentrations of 0.25 %, 0.1 % and 0.05 % (w/v) as formulations in an appropriate vehicle (DMF) was shown to have skin sensitization potential.Based on the EC3 values calculated using dose-response and regression curve analysis the test item was considered as strong/extreme skin sensitizer.