5-(4-hydroxyphenyl)imidazolidine-2,4-dione

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

end on 19-APR-2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: study performed according to OECD guideline, not GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

no

Type of study:

guinea pig maximisation test

Test material

Test material information

Constituent 1

Reference substance name:

5-(phenylmethyl)imidazolidine-2,4-dione

EC Number:

222-563-3

EC Name:

5-(phenylmethyl)imidazolidine-2,4-dione

Cas Number:

3530-82-3

IUPAC Name:

5-benzylimidazolidine-2,4-dione

Details on test material:

- Name of test material (as cited in study report): BHT
- Molecular formula (if other than submission substance): C10H10N2O2
- Molecular weight (if other than submission substance): 190.20
- Smiles notation (if other than submission substance): N1C(N[C@@H](C1=O)Cc1ccccc1)=O
- InChl (if other than submission substance): InChI=1/C10H10N2O2/c13-9-8(11-10(14)12-9)6-7-4-2-1-3-5-7/h1-5,8H,6H2,(H2,11,12,13,14)
- Structural formula attached as image file (if other than submission substance): see Fig. attached
- Substance type: monoconstituent substance
- Physical state: powder
- Stability under test conditions: data not available
- Storage condition of test material: at room temperature in the dark

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Kisslegg, Germany
- Age at study initiation: young adult animals (approx. 4 weeks old)
- Weight at study initiation: 338 g +/- 21 g on Day 1
- Housing: group housing of 5 animals per labelled metal cage with wire-mesh floors
- Diet: free access to standard guinea pig diet, including ascorbic acid (1 000 mg/kg); (Charles River Breeding and Maintenance Diet for Guinea Pigs, Altromin, Lage, Germany). Hay (B.M.I., Helmond, The Netherlands) was provided once a week.
- Water: Free access to tap water.
- Acclimation period: at least 5 days before the start of treatment under laboratory conditions

ENVIRONMENTAL CONDITIONS
- Temperature: 21 °C
- Humidity: 30-70%
- Air changes: approximately 15 air changes per hour
- Photoperiod: 12 hours artificial fluorescent light and 12 hours dark per day

IN-LIFE DATES: data not available

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

aqueous 1%

Induction 2

Concentration / amount:

induction (intradermal): 1%
induction (epidermal): 50%
challenge (epidermal): 50%

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

aqueous 1%

Challenge 2

Concentration / amount:

induction (intradermal): 1%
induction (epidermal): 50%
challenge (epidermal): 50%

No. of animals per dose:

Experimental group: 10 females.
Control group: 5 females.

Details on study design:

RANGE FINDING TESTS:
lntradermal iniections:
A series of four test substance concentrations was used, the highest concentration being the maximum concentration that could technically be injected. Each of two animals received two different concentrations in duplicate (0.1 mllsite) in the clipped scapular region. The injection sites were assessed for irritation 24 and 48 hours after treatment.
Epidermal application:
A series of four test substance concentrations was used, the highest concentration being the maximum concentration that could technically be applied. Two different concentrations were applied (0.5 ml each) per animal to the clipped flank, using Metalline patches (2x3 cm) mounted on Medical tape which were held in place with Micropore tape and subsequently a Coban elastic bandage.
The animals receiving intradermal injections were treated with the lowest concentrations and two further animals with the highest concentrations.
After 24 hours, the dressing was removed and the skin cleaned of residual test substance using water. The treated skin areas were assessed for irritation 24 and 48 hours after exposure.

MAIN STUDY
A. INDUCTION EXPOSURE
INDUCTION - Experimental animals:
Day 1 The scapular region was clipped and three pairs of intradermal injections (0.1 ml/site) were made in this area as follows:
A) A 1 :1 w/w mixture of Freunds' Complete Adjuvant (Difco, Detroit, U.S.A.) with water for injection (Fresenius AG, Bad Homburg, Germany).
B) The test substance at a 1 % concentration.
C) A 1 :1 w/w mixture of the test substance, at twice the concentration used in (B) and Freunds' Complete Adjuvant.
Day 3 The dermal reactions caused by the intradermal injections were assessed for irritation.
Day 7 The scapular area between the injection sites was clipped and subsequently rubbed with 10% sodium-dodecyl-sulfate (SDS, Boom, Meppel, The Netherlands) in vaseline using a spatula. This concentration of SDS provokes a mild inflammatory reaction.
Day 8 The 10% SDS treated area between the injection sites was treated with 0.5 ml of a 50% test substance concentration using a Metalline patch (2x3 cm) mounted on Medical tape, which was held in place with Micropore tape and subsequently Coban elastic bandage.
The dressing was removed after 48 hours exposure, the skin cleaned of residual test substance using water and the dermal reactions caused by the epidermal exposure were assessed for irritation.
INDUCTION - Control animals:
The control animals were treated as described for the experimental animals except that, instead of the test substance, vehicle alone was administered.

B. CHALLENGE EXPOSURE (all animals)
Day 21 One flank of all animals was clipped and treated by epidermal application of a 50% test substance concentration and the vehicle (0.1 5 ml each), using Patch Test Plasters (Leukotest , Beiersdorf Medical, Almere, The Netherlands). The patches were held in place with Micropore tape and subsequently Coban elastic bandage.
The dressing was removed after 24 hours exposure and the skin cleaned of residual test substance and vehicle using water. The treated sites were assessed for challenge reactions 24 and 48 hours after removal of the dressing.

Positive control substance(s):

yes

Remarks:

ALPHA-HEXYLCINNAMICALDEHYDE

Results and discussion

Positive control results:

The skin reactions in eight experimental animals observed in response to the 10% test substance concentration in the challenge phase were considered indicative of sensitisation, based on the absence of any response in the control animals. These results lead to a sensitisation rate of 80 per cent to the 10% concentration. From these results, it was concluded that the female guinea pig of the albino Dunkin Hartley strain is an appropriate animal model for the performance of studies designed to evaluate the sensitising potential of a substance in a Maximisation type of test.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

no effect

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 0%. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no effect.

Results 2

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no effect

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no effect.

Results 3

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

no effect

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0%. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no effect.

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no effect

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no effect.

Results 5

Reading:

other: 1st and 2nd reading

Group:

positive control

Dose level:

10%

No. with + reactions:

8

Total no. in group:

10

Remarks on result:

other: Reading: other: 1st and 2nd reading. Group: positive control. Dose level: 10%. No with. + reactions: 8.0. Total no. in groups: 10.0.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

BHT is not sensitising to the skin in the guinea pig Maximisation test

Executive summary:

In a dermal sensitization study with BHT in 1% aqueous carboxymethyl cellulose, young adult Dunkin Hartley strain, albino guinea pig (15 females) were tested using the method of Maximisation (OECD 406, not GLP).

Test substance concentrations selected for the main study were based on the results of a preliminary study.

In the main study, ten experimental animals were intradermally injected with a 1 % concentration and epidermally exposed to a 50% concentration. Five control animals were similarly treated, but with vehicle alone (1% aqueous carboxymethyl cellulose). Approximately 24 hours before the epidermal induction exposure all animals were treated with 10% SDS.

Two weeks after the epidermal application all animals were challenged with a 50% test substance concentration and the vehicle.

 

No skin reactions were evident after the challenge exposure in the experimental and control animals.

There was no evidence that BHT had caused skin hypersensitivity in the guinea pig, since no responses were observed in the experimental animals in the challenge phase. This result indicates a sensitisation rate of 0 per cent.

 

Based on these results and according to the EC criteria for classification and labelling requirements for dangerous substances and preparations (DSD directive and CLP regulation), BHT does not have to be classified and has no obligatory labelling requirement for sensitisation by skin contact.