Distillates (coal tar), benzole fraction

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented publication which meets basic scientific principles (limited reporting on individual test data)

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1986

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The objective of the study was the method development and evaluation of the mouse ear swelling test. After having identified the most suitable test conditions, the test method was evaluated using 72 substances already rated as sensitizers or non sensizisers, based on results of independent sensitisation tests.
Mice are induced with test substance by daily epicutaneous applications on the abdomen for 4 days. After a rest period of 7 days, the challenge dose is applied to the ear of mice. 24 and 48 h later, the ear thickness is determined.

GLP compliance:

no

Type of study:

mouse ear swelling test

Justification for non-LLNA method:

In vivo skin sensitisation studies that were carried out or initiated before 10 May 2017, and that meet the requirements set out in Article 13(3), first subparagraph, and Article 13(4) shall be considered appropriate to address this standard information requirement.

Test material

Test material information

Constituent 1

Reference substance name:

Benzene

EC Number:

200-753-7

EC Name:

Benzene

Cas Number:

71-43-2

Molecular formula:

C6H6

IUPAC Name:

benzene

Details on test material:

- Name of test material (as cited in study report): benzene
- Analytical purity: ≥ 98%

In vivo test system

Test animals

Species:

mouse

Strain:

CF-1

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River breeding laboratories
- Age at study initiation: 6 to 8 weeks
- Weight at study initiation: no data
- Housing: 5 per cage in wire-bottom stainless-steel cages
- Diet (e.g. ad libitum): Purina Rodent Laboratory Chow 5001; ad libitum
- Water (e.g. ad libitum): water ad libitum
- Acclimation period: at least 5 days

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, open

Vehicle:

unchanged (no vehicle)

Concentration / amount:

100 µl

Day(s)/duration:

10

Challenge

No.:

#1

Route:

epicutaneous, open

Vehicle:

unchanged (no vehicle)

Concentration / amount:

100 µl

Day(s)/duration:

day 10

No. of animals per dose:

10 or 15

Details on study design:

RANGE FINDING TESTS: no data

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 4
- Exposure period: 10 days
- Test groups: 1 (10 or 15 animals)
- Control group: 1 (5 or 10 animals)
- Site: abdomen
- Frequency of applications: daily
- Duration: 4 days
- Concentrations: 100 µL pure test substance was topically applied to the center of the shaved area

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: day 10 of experiment
- Exposure period: single exposure
- Test groups: 1
- Control group: 1
- Site: left ear
- Concentrations: 100 µL pure test substance
- Evaluation (hr after challenge): 24 and 48 h (measurement of ear thickness)

OTHER
- During induction, prior to topical application of test substance, the application site was tape stripped.
- On day 0 (first day of induction) before tape stripping and topical application of test substance, two intradermal injections
of Freund's complete adjuvans totalling 0.05 mL were applied to the center of the shaved abdominal induction site.

Challenge controls:

The right ear of the test animals was used as control. It was treated the same way as the left (test) ear without applying test substance.

Results and discussion

In vivo (non-LLNA)

Results

Reading:

1st reading

Dose level:

100µL

No. with + reactions:

0

Total no. in group:

15

Any other information on results incl. tables

Mouse ear swelling test

Based on ear thickness measurements, 0% of test animals was sensitised. Thickness of treated left ears was not increased compared to thickness of control right ears (100 % swelling; % ear swelling = test ear thickness / control ear thickness * 100). Benzene was demonstrated to be not sensitising in this mouse ear swelling test (no details on results are reported).

 

Guinea pig maximisation test

In the guinea pig maximisation test, 0% sensitised test animals were observed. Benzene was not sensitising in this test (no details on results are reported).

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Benzene was tested undiluted (no vehicle) for skin sensitisation in a mouse ear swelling test and in a guinea pig maximisation test. In both tests, no evidence was observed for a skin sensitising potential of benzene. Based on these test results, benzene is not skin sensitising.