Fluorobenzene

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-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 1

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Reference 2

Reference Type:

publication

Title:

Toxicological Evaluations Vol. 13

Author:

BG Chemie

Year:

1998

Bibliographic source:

Springer-Verlag Berlin Heidelberg, ISBN 3-540-62658-1

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

An appropriate guinea pig maximisation test was already available which does not justify conducting an additional LLNA due to animal welfare.

Test material

Test material information

Constituent 1

Reference substance name:

Fluorobenzene

EC Number:

207-321-7

EC Name:

Fluorobenzene

Cas Number:

462-06-6

Molecular formula:

C6H5F

IUPAC Name:

fluorobenzene

Details on test material:

- Name of test material (as cited in study report): Fluorobenzene
- Analytical purity: 99.7%
- Batch No. 01420
- Physical state: colourless liquid
- Storage condition of test material: in the refrigerator at 4°C

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: David Hall Limited, Darley Oaks, Newchurch, Burton-on-Trent, Staffordshire
- Age at study initiation: young adult (less than one year old)
- Weight at study initiation: 361-455 g
- Housing: in groups of 5 per aluminium cage
- Diet: FDI Guinea Pig Diet (Special Diets Services Limited, 1 Stepfield, Witham, Essex, CM8 3AD), supplemented with hay, ad libitum
- Water: tap water ad libitum
- Acclimation period: at least 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-22
- Humidity (%): 56 (mean)
- Photoperiod (hrs dark / hrs light): 12 / 12

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

paraffin oil

Concentration / amount:

1) 0.10 mL Freund's Complete Adjuvant
2) 0.10 mL test material 10% v/v paraffin oil
3) 0.10 ml of a 50:50 emulsion of test material in Freund's Complete Adjuvant

Day(s)/duration:

24 h

Induction 2

Route:

epicutaneous, occlusive

Vehicle:

paraffin oil

Concentration / amount:

Wetted Whatman paper charged with 100% test material

Day(s)/duration:

48 h

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Concentration / amount:

100 % of test material in paraffin oil

Day(s)/duration:

24 h

Adequacy of challenge:

other: maximum technically feasible

No. of animals per dose:

20

Details on study design:

The test was carried out using the following method:
1) Induction: A preliminary dose ranging test was carried out to assess suitable concentrations for injection and topical application on 4 previously untreated guinea pigs. Injections were in the shaved scapular region and topical application was on the shaved flanks. Two guinea pigs were subjected
to intradermal injections and a further 2 guinea pigs were exposed to topical application for 48 h of the test material at 4 different concentrations (injections 25%, 10%, 5% and 1% v/v in paraffin oil; topical application 100%, 50%, 25% and 10% v/v in paraffin oil). The injection sites were assessed for irritation 24, 48 and 72 h after injection, and the topical application sites were assessed for irritation 24 and 48 h after patch removal. Assessments were made using Scale A to be described.
Main Test - Injection Phase: In the main test, hair was shaved from an area 4 cm x 6 cm across the scapular region of 44 guinea pigs. These animals were allocated as follows: test group 20 guinea pigs, control group 20 guinea pigs, challenge dose ranging group 4 guinea pigs. The test group guinea pigs were each given 6 intradermal injections, 3 in a line each side of and parallel to the mid-line in the shaved region as follows: 0.10 ml Freund's Complete Adjuvant (anterior injection), 0.10 ml test material (middle injection), 0.10 ml of a 50:50 emulsion of test material in Freund's Complete Adjuvant (posterior injection). The test material was injected at a concentration of 10% v/v in paraffin oil. The concentration of Fluorobenzene in Freund's Complete Adjuvant was 10%. The 20 control group guinea pigs were similarly treated, but with the vehicle, paraffin oil, replacing the test material. One hour and 24 h after injection, the treated sites of both test and control groups were assessed for irritation using Scale A to be described. The 4 guinea pigs intended for dose ranging for challenge were each given a 0.1 ml intradermal injection of Freund's Complete Adjuvant on either side of the mid-line of the shaved scapular region.
Main Test - Topical Application Phase: Six days after the injection phase, the injection site of each of the test and control group animals was shaved again and then wetted with 10% aqueous SLS to provoke a mild inflammatory response to enhance the possibility of sensitisation. After 24 h, a 2 cm x 4 cm patch of Whatman chromatography paper, charged with the test material at a concentration of 100%, was applied to the pretreated area of each of the test group animals. The patch was covered by an overlapping piece of impermeable plastic adhesive tape (Blenderm). The whole area was then firmly bound with Sleek occlusive tape, and the dressing was left in place for 48 h before removal. The control group guinea pigs were similarly treated, but with the vehicle, paraffin oil, replacing the test material. One hour and 24 h after patch removal, the treated sites of both test and control groups were assessed for irritation using Scale A to be described. The 4 guinea pigs intended for dose ranging for challenge were untreated at this stage.
Assessment of Response at Induction according to Scale A: 0 = no visible change, 1 = slight reaction, 2 = moderate reaction, 3 = severe reaction and/or necrosis.

2) Challenge: Before challenging the test animals, a maximum non-irritant concentration of the test material was determined in a preliminary experiment on 4 dose ranging guinea pigs. The animals were pretreated at the induction phase with Freund's Complete Adjuvant only. The test material was applied to the shaved flanks of the guinea pigs for 24 h at concentrations of 100%,, 50%, 25% and 10% v/v in paraffin oil using the same method as topical induction. Reactions were assessed 24 h later using Scale B to be described.
Main Test - Challenge Phase: Two weeks after the start of topical induction, both the test and control group guinea pigs were challenged with the test material, Fluorobenzene, at a concentration of 100% and with the vehicle, paraffin oil. A 5 cm x 5 cm area of the left flank was shaved and the test and control materials were applied to the prepared test site on 2 cm x 2 cm pieces of filter paper. The patches were held in place for 24 h using the same method as topical induction, after which time they were removed. The degree of response was determined by trained assessors 24 and 48 h after removal of the challenge patch when an allergic response would be at a peak. The animals were shaved 3 h prior to the first challenge assessment. Any animal showing erythema at the site of challenge was considered to have shown a positive response.
Assessment of Response at Challenge according to Scale B: 0 = no visible change, 1 = slight or discrete erythema, 2 = moderate and confluent erythema, 3 = intense erythema and/or edema.

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Any other information on results incl. tables

Dose Ranging Test for Induction: Slight to moderate irritation was noted at sites injected with Fluorobenzene at concentrations of 25% and 10% v/v in paraffin oil. A concentration of 10% v/v in paraffin oil was selected for the injection phase of induction in the test group. No irritation was noted at sites treated topically with the test material. A concentration of 100% was selected for the topical application phase of induction in the test group.

 

Main Test – Induction: Slight irritation was noted in the test and control groups. Dose Ranging Test for Challenge: No irritation was noted at sites treated topically with Fluorobenzene at concentrations of 100%, 50%, 25% and 10% v/v in paraffin oil. A concentration of 100% was selected for challenge.

 

Main Test – Challenge: Following challenge with Fluorobenzene at a concentration of 100%, none of the 20 test group animals showed positive reactions to this application. None of the 20 control group animals, which had previously only been exposed to the vehicle, paraffin oil, showed a positive reaction to this application. There was no reaction in the test or control groups to challenge with the vehicle, paraffin oil.

 

Body Weight: Body weights were recorded at main test commencement and on test completion. Body weight gains were acceptable.

 

Clinical Signs: No clinical signs, other than skin reactions induced by treatment, were noted.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

There is no evidence from the test results that Fluorobenzene is a sensitiser in guinea pigs.