4-chlororesorcinol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06.10.2003 - 10.05.2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

Deviations from the minimum level for relative humidity and temperature occurred. The initially treated animals exceeded the maximum age of 12 weeks as protocolled with two weeks. These protocol deviations did not aversely affect the study integrity.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

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:

4-chlororesorcinol

EC Number:

202-462-0

EC Name:

4-chlororesorcinol

Cas Number:

95-88-5

Molecular formula:

C6H5ClO2

IUPAC Name:

4-chlorobenzene-1,3-diol

Test material form:

other:

Remarks:

beige powder

Details on test material:

Molecular weight: 144.65

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Age:
Initially treated animals approx. 14 weeks old and the additionally treated animals approx. 10 weeks old
Body weight:
Variation was within +/- 20% of the sex mean
Conditions:
Animals were housed in a controlled environment, in which optimal conditions were considered to be approximately 15 air changes per hour, a temperature of 21.0 + 3.0°C (actual range: 18.8 -23.1 "C), a relative humidity of 30-70% (actual range: 29 - 70%) and 12 hours artificial fluorescent light and 12 hours darkness per day.
Accommodation:
Individual housing in labelled Macrolon cages (type I; height 12.5 cm) containing purified sawdust as bedding material (Woody-Clean type 314; Tecnilab-BMI BV, Someren , TheNetherlands). The acclimatisation period was at least 5 days before the start of treatment under laboratory conditions. Animals were group housed in polycarbonate cages (Macrolon II type; height 15 cm) during the acclimatisation period.
Diet:
Free access to standard pelleted laboratory animal diet.
Water:
Free access to tap-water.

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

2.5%, 5%, 10%, 25%

No. of animals per dose:

5

Details on study design:

Preliminary irritation study
A preliminary irritation study was conducted in order to select the highest test substance concentration to be used in the main study. In principle, this concen-
tration should be well tolerated systemically by the animals and may give moderate irritation (grade 3) at the highest. A series of four test substance concen-
trations were tested, the highest concentration being the maximum concentration that could technically be applied. The starting- and subsequent
concentrations were taken from the series: 100% (undiluted), 50%, 25%, 10%, 5%, 2.5%, 1% and if needed further lower concentrations using the same steps. The test system, procedures and techniques were identical to those used during days 1 to 3 of the main study unless otherwise specified.
Four young adult animals were selected (5-14 weeks old). Each animal was treated with one concentration on two consecutive days. Approximately 4 hours after the last exposure, the skin was cleaned of residual test substance with water and the irritation was assessed. No necropsy was performed and no bodyweights were determined after termination.

Main study
Test substance concentrations selected for the main study were based on the results of a preliminary study.
In the main study, three groups of five experimental animals were epidermally exposed to a 5%, 25% and 50% concentration respectively on three consecutive days. Five vehicle control animals were similarly treated, but with vehicle alone (Acetone/Olive oil (4:1 v/v).
Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised.
After precipitating the DNA of the lymph node cells, radioactivity measurements were done. Based on the results, additional groups were treated at 2.5 and 10%. Five vehicle control animals were similarly treated, but with vehicle alone. Four animals treated at 50% were found dead on day 3.

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

1.1

Test group / Remarks:

2,5% test substance

Remarks on result:

other: experimental

Results 2

Parameter:

SI

Value:

1.5

Test group / Remarks:

5% test substance

Remarks on result:

other: experimental

Results 3

Parameter:

SI

Value:

10.1

Test group / Remarks:

10% test substance

Remarks on result:

other: experimental

Results 4

Parameter:

SI

Value:

16.4

Test group / Remarks:

25% test substance

Remarks on result:

other: experimental

Results 5

Parameter:

SI

Test group / Remarks:

50% test substance

Remarks on result:

other: experimental

Results 6

Parameter:

SI

Value:

1

Test group / Remarks:

AcetoneIOlive oil (4:1 V/V)

Remarks on result:

other: vehicle control

Applicant's summary and conclusion

Interpretation of results:

sensitising

Conclusions:

The SI values calculated for the substance concentrations 2.5, 5, 10 and 25% were 1.1, 1.5, 10.1, 16.4 respectively. These data showed a dose-response and an EC3 value of 5.8% was calculated.
Based on these results and according to the recommendations made in the test guidelines (OECD No.429, EC 8.42 and EPA OPPTS 870.2600), A 012 should be regarded as a skin sensitiser.
Based on these results and according to the:
- OECD Harmonized lntegrated Hazard Classification System for Human Health and Environmental Effects of Chemical Substances (OECD, 1998), A 012 should be classified as contact sensitiser.
- EC criteria for classification and labelling requirements for dangerous substances and preparations (Council Directive 67/548/EEC), A 012 should be labelled as:
may cause sensitisation by skin contact (R 43).

Executive summary:

Assessment for Contact Hypersensitiviiy to A 012 in the Mouse (Local Lymph Node Assay).

The study was carried out based on the guidelines described in: OECD, Section 4, Health Effects, No.429 (2002), Paris Cedex; EC, Council Directive 67/548/EEC, Annex IV C, B.42 (Draft) (2001); Environmental Protection Agency (EPA): Health Effects Test Guidelines OPPTS 870.2600. "Skin Sensitisation" 2003.

Test substance concentrations selected for the main study were based on the results of a preliminary study. In the main study, three groups of five experimental animals were epidermally exposed to a 5%, 25% and 50% concentration respectively on three consecutive days. Five vehicle control animals were similarly treated, but with vehicle alone (Acetone/Olive oil (4:1 V/V).

Three days after the last exposure, all animals were injected with ³H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised.

After precipitating the DNA of the lymph node cells, radioactiviiy measurements were done. Based on the results, additional groups were treated at 2.5 and 10%. Five vehicle control animals were similarly treated, but with vehicle alone.

Four animals treated at 50% were found dead on day 3. Macroscopic post mortem examination revealed no abnormalities. No further mortaliiy occurred and no symptoms of systemic toxiciiy were observed in the surviving animals of the main study.

The sizes of the nodes of the 2.5 and 5% groups were considered to be normal. Enlarged nodes were found in the 10, 25 and 50% groups. One very large node was found in one control animal. No other macroscopic abnormalities of the nodes were noted.

Mean DPM/animal values for the experimental groups treated with test substance concentrations 5 and 25 % were 232 and 2473 respectively. The DPM Value for the only surviving animal treated at 50% was 2402. The mean DPM/animal value for the vehicle control group was 151.

In order to achieve more information regarding the SI=3 value, additional groups of animals were treated. Mean DPM/animal values for the experimental groups treated with test substance concentrations 2.5 and 10% were 145 and 1351 respectively. The mean DPM/animal value for the vehicle control group was 134.

The SI values calculated for the substance concentrations 2.5, 5, 10 and 25% were 1.1, 1.5, 10.1, 16.4 respectively.

These data showed a dose-response and an EC3 value of 5.8% was calculated.

Based on these results and according to the recommendations made in the test guidelines (OECD No.429, EC B.42 and EPA OPPTS 870.2600), A 012 should be regarded as a skin sensitiser.

Based on these results and according to the:

- OECD Harmonized lntegrated Hazard Classification System for Human Health and Environmental Effects of Chemical Substances (OECD, 1998), A 012 should be classified as contact sensitiser.

- EC criteria for classification and labelling requirements for dangerous substances and preparations (Council Directive 67/548/EEC), A 012 should be labelled as: may cause sensitisation by skin contact (R 43).