Bontron E-108

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 December 2000 to 20 January 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 28/02/2000 Date of signature: 26/04/2000

Type of study:

guinea pig maximisation test

Test material

Test material information

Constituent 1

Details on test material:

Sponsor's identification :S178207
Description : white powder
Batch number : SBT-5-0254
Date received : 08 November 2000
Storage conditions :room temperature in the dark

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: David Hall Limited, Burton-on-Trent, Staffordshire, UK and Harlan UK Ltd., Blackthorn, Bicester, Oxon, UK.
- Age at study initiation: approximately eight to twelve weeks old.
- Weight at study initiation: 487 to 590g
- Housing: were housed singly or in pairs in solid-floor polypropylene cages furnished with woodflakes.
- Diet: - ad libitum (Guinea Pig FD1 Diet, Special Diets Services Limited, Witham, Essex, UK)
- Water: - ad libitum (mains tap water)
- Acclimation period:at least five days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 to 23°C
- Humidity (%): 30 to 70%
- Air changes (per hr): at least fifteen changes per hour
- Photoperiod (hrs dark / hrs light):lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness


IN-LIFE DATES: From: Day 0 To: Day 23 (48 hours after challenge)

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

arachis oil

Induction 2

Concentration / amount:

Intradermal Induction :5% w/w in arachis oil BP
Topical Induction :25% w/w in arachis oil BP
Topical Challenge :2% and 1% w/w in arachis oil BP

Challenge

Challenge 1

Route:

epicutaneous, semiocclusive

Vehicle:

arachis oil

Challenge 2

Concentration / amount:

Intradermal Induction :5% w/w in arachis oil BP
Topical Induction :25% w/w in arachis oil BP
Topical Challenge :2% and 1% w/w in arachis oil BP

No. of animals per dose:

A group of 15 guinea pigs was used for the main study, ten test and five control.

Details on study design:

RANGE FINDING TESTS:

Selection of Concentrations for Main Study (Sighting Tests)
The concentrations of test material to be used at each stage of the main study were determined by 'sighting tests' in which groups of guinea pigs were treated with various concentrations of test material. The procedures were as follows:

Selection of Concentration for Intradermal Induction
Intradermal injections (0.1 ml/injection site) were made on the clipped shoulder of two guinea pigs, using a range of concentrations (1% and 5% w/w in arachis oil BP). The degree of erythema at the injection sites was assessed approximately 24, 48, 72 hours and 7 days after injection. The degree of oedema was not evaluated. Any evidence of systemic toxicity was also recorded. The highest concentration that caused only mild to moderate skin irritation, and which was well tolerated systemically, was selected for the intradermal induction stage of the main study.

Selection of Concentration for Topical Induction
Two guinea pigs (intradermally injected with Freund's Complete Adjuvant nine days earlier) were treated with four preparations of the test material (50%, 25%, 10% and 5% w/w in arachis oil BP). Applications were made to the clipped flanks under occlusive dressings for an exposure period of 48 hours. The degree of erythema and oedema was evaluated approximately 1, 24 and 48 hours after dressing removal. The highest concentration producing only mild to moderate dermal irritation was selected for the topical induction stage of the main study.

Selection of Concentration for Topical Challenge
Four preparations of the test material (25%, 10%, 5% and 2% w/w in arachis oil BP) were applied to the clipped flanks of two guinea pigs under occlusive dressings for an exposure period of 24 hours. These guinea pigs did not form part of the main study but had been treated identically to the control animals of the main study, up to Day 14. The degree of erythema and oedema was evaluated approximately 1, 24 and 48 hours after dressing removal. The highest non-irritant concentration of the test material and one lower concentration were selected for the topical challenge stage of the main study.


MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3 separate injections

- Exposure period: not applicable, as exposure by intradermal injection

- Test groups: 15 guinea pigs

- Control group: 5 guinea pigs - test material omitted from the intradermal injections. Injection b) was therefore the vehicle alone, injection c) was a 50% formulation of the vehicle in a 1:1 preparation of Freund’s Complete Adjuvant plus distilled water.

- Site: A row of three injections (0.1 ml each) was made on each side of the mid-line into a 20 mm x 40 mm area.

- Frequency of applications: 1 intradermal injection only

- Duration: not applicable

- Concentrations: The injections were:
a) Freund's Complete Adjuvant plus distilled water in the ratio 1:1
b) a 5% w/w formulation of the test material in arachis oil BP
c) a 5% w/w formulation of the test material in a 1:1 preparation of Freund's Complete Adjuvant plus distilled water.



B. CHALLENGE EXPOSURE
- No. of exposures: 1 (either 2% w/w or 1% w/w)

- Day(s) of challenge: Day 21

- Exposure period: 24 hours

- Test groups: 15 guinea pigs

- Control group: 5 guinea pigs

- Site: an area of approximately 50 mm x 70 mm on both flanks of each animal, was clipped free of hair with veterinary clippers

- Concentrations: maximum non-irritant concentration (2% w/w in arachis oil BP). To ensure that the maximum non-irritant concentration was used at challenge, the test material at a concentration of 1% w/w in arachis oil BP was similarly applied to a skin site on the left shorn flank.

- Evaluation (hr after challenge): Approximately 24 and 48 hours after challenge dressing removal, the degree of erythema and oedema was quantified

Challenge controls:

Challenge of control animals not described in report.

Positive control substance(s):

yes

Remarks:

2-Mercaptobenzothiazole

Results and discussion

Positive control results:

2-mercaptobenzothiazole achieved either a 90% or 100% positive response in six control studies conducted in the three years prior to the study.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No erythema or oedema recorded.

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 1%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No erythema or oedema recorded..

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No erythema or oedema noted

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 1%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No erythema or oedema noted.

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

2%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No erythema or oedema noted

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 2%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No erythema or oedema noted.

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No erythema or oedema noted

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 2%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No erythema or oedema noted.

Any other information on results incl. tables

 Skin Reactions Observed After Intradermal Induction

Moderate and confluent erythema was noted at the intradermal induction sites of test group animals.

Skin Reactions Observed After Topical Induction

Discrete or patchy to moderate and confluent erythema and very slight oedema were noted at the topical induction sites of test group animals.

Skin Reactions Observed in Main Study After Topical Challenge

2% w/w in Arachis Oil BP

No skin reactions were noted at the challenge sites of the test or control group animals at the 24 or 48-hour observations.

1% w/w in Arachis Oil BP

No skin reactions were noted at the challenge sites of the test or control group animals at the 24 or 48-hour observations.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test material produced a 0% (0/9) sensitisation rate and was classified as a non-sensitiser to guinea pig skin under the conditions of the test.

Executive summary:

Introduction. The study was performed to assess the contact sensitisation potential of the test material in the albino guinea pig. The method was designed to meet the requirements of the following:

§        OECD Guidelines for the Testing of Chemicals No. 406 “Skin Sensitisation” (adopted 17 July 1992)

§        Commission Directive 96/54/EC Method B6 Acute Toxicity (Skin Sensitisation)

Method. Ten test and five control animals were used for the study. Two phases were involved in the main study; an induction of a response by intradermal injection and topical application and a topical challenge of that response.

Based on the results of sighting tests, the concentrations of test material for the induction and challenge phases were selected as:

Intradermal Induction               :          5% w/w in arachis oil BP

Topical Induction                     :          25% w/w in arachis oil BP

Topical Challenge                    :          2% and 1% w/w in arachis oil BP

Conclusion. Under the conditions of the test, the test material produced a 0% (0/9) sensitisation rate and was classified as a non-sensitiser to guinea pig skin.

The test material did not meet the criteria for classification as a sensitiser according to EU labelling regulations Commission Directive 93/21/EEC. No symbol and risk phrase are required.