2,3-dichlorobenzoic acid

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:

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-dichlorobenzoic acid

EC Number:

200-039-5

EC Name:

2,3-dichlorobenzoic acid

Cas Number:

50-45-3

Molecular formula:

C7H4Cl2O2

IUPAC Name:

2,3-dichlorobenzoic acid

Test material form:

solid: crystalline

Details on test material:

Test item: 2,3-DICHLOROBENZOIC ACID (CAS No.: 50-45-3)
Batch No.: L2A134N
Physical state: Solid, crystalline powder
Colour: White
Active ingredient content (titrimetry): 100.4%
Water content: 0.03 % (m/m)
Storage: 15-30°C, protected from moisture

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; 11-12 weeks old (at start of the main test)
Body weight range at starting: 17.0-22.0 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 (50; 25; 10; 5 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 the best solvent and the maximum applicable concentration according to the relevant guidelines. The test item was tested at the solubility limit of 50 % and at three lower concentrations (25 %, 10 % and 5 %) in 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 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 = 8.1). 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

Value:

0.7

Variability:

2,3-DICHLOROBENZOIC ACID 50% in DMF

Results 2

Parameter:

SI

Value:

0.9

Variability:

2,3-DICHLOROBENZOIC ACID 25% in DMF

Results 3

Parameter:

SI

Value:

1.9

Variability:

2,3-DICHLOROBENZOIC ACID 10 % in DMF

Results 4

Parameter:

SI

Value:

1.7

Variability:

2,3-DICHLOROBENZOIC ACID 5% in DMF

Any other information on results incl. tables

Test Group Name	Measured DPM/group	Group* DPM	DPN (DPM/Node)	Stimulation IndexValues
Vehicle control for the positive control: AOO	17750	17710.5	2213.8	1.0
Positive control: 25% HCA in AOO	144132	144092.5	18011.6	8.1
2,3-DICHLOROBENZOIC ACID 50% in DMF	4734	4694.5	586.8	0.7
2,3-DICHLOROBENZOIC ACID 25% in DMF	6703	6663.5	832.9	0.9
2,3-DICHLOROBENZOIC ACID 10 % in DMF	13746	13706.5	1713.3	1.9
2,3-DICHLOROBENZOIC ACID 5% in DMF	12192	12152.5	1519.1	1.7
Vehicle control :for the test item: DMF	7226	7186.5	898.3	1.0

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

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information

Conclusions:

Under the conditions of the present Local Lymph Node Assay, 2,3-DICHLOROBENZOIC ACID (CAS No. 50-45-3) tested at the maximum attainable concentration of 50 % (w/v, based on solubility) and at concentrations of 25 %, 10% and 5% as formulations in an appropriate vehicle (DMF) was shown to have no sensitization potential.