Reaction products of 2-methylimidazole and 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

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:

other: The study was conducted according to the O.E.C.D. test guideline 406 with GLP compliance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Existing study available.

Test material

Test material information

Constituent 1

Reference substance name:

Reaction products of 2-methylimidazole and 2,2'-[(1- methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

EC Number:

701-436-0

Molecular formula:

(C15H16O2.C4H6N2.C3H5ClO)x

IUPAC Name:

Reaction products of 2-methylimidazole and 2,2'-[(1- methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

As per IUCLID5 Sections 1.1. 1.2. 1.4. and 4.1.

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

Young female nulliparous, non-pregnant albino guinea pigs of the Dunkin Hartley strain within the weight range 250-300gm were acquired from D.Hall, Darley Oaks, Burton-on-Trent, Staffordshire. The animals were housed in groups of up to 5 in stainless steel cages. A pelleted diet, SQC FDI guinea pig diet with added vitamin C (Special Diets Services, Witham, Essex) and mains drinking water were freely available.

The animal room was air conditioned with temperature in the range 18-26° C and relative humidity in the range 33-52% during the acclimatisation and study periods. Fluorescent lighting was controlled to give an artificial cycle of 12 hours light (0600-1800 hours)/12 hours dark per day.

The animals were acclimatised for 18 days the main study.

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

other: Ethanol for epicutaneous induction and Challenge phases. Corn oil was the vehicle used for the intradermal injections.

Induction 2

Concentration / amount:

25 % w/v for epicutaneous induction and the Challenge phase.

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

other: Ethanol for epicutaneous induction and Challenge phases. Corn oil was the vehicle used for the intradermal injections.

Challenge 2

Concentration / amount:

25 % w/v for epicutaneous induction and the Challenge phase.

No. of animals per dose:

20

Details on study design:

For the Maximization test thirty healthy animals within the weight range 430-492gm were selected for the study and randomly allocated to a group of 20 test animals and 10 control animals using a stratified bodyweight procedure. The dorsal area between the shoulders of each animal was clipped free of fur and 3 pairs of intradermal injections made within this area. Each injection was 0.lml and each pair of injections consisted of:

A) Test Group
1) 50% v/v Freund’s Complete Adjuvant (FCA) emulsified in water.
2) 0.1% w/v concentration of the test substance article in corn oil.
3) Test substance mixed with FCA and then emulsified 1:1 with water to give a final 0.1% w/v concentration of test substance.

B) Control Group
1) 50% v/v Freund’s Complete Adjuvant emulsified in water.
2) Corn oil.
3) Corn oil mixed with FCA and then emulsified 1:1 with water to give a final corn oil concentration o 50%.

Twenty four hours after administration of the intradermal induction all animals were examined for signs of irritation in the treated area. Moderate skin irritation was noted at the treated site on all animals in the test and control groups.

Six days after this intradermal induction, the injection sites on all test and control animals were painted with 0.5m1 10% sodium lauryl sulphate in order to provoke localised skin irritation. On the following day, the injection process was boosted by topical application of 25% w/v test substance in ethanol over the injection sites of the test animals. The injection sites of all animals were clipped free of fur and patches of Whatman No. 3 filter paper, 4 x 2cm, were saturated with 25% test substance and placed over the injection sites of animals in the test group. A strip of 5cm wide “Blenderm” surgical tape was placed over each patch to act as an occlusive barrier and the whole assembly held in position by wrapping the animals with a length of 5cm wide “Elastoplast” elastic adhesive bandage. Animals of the control group were similarly treated, the patch of filter paper being saturated with ethanol. The patches and dressings were removed from all animals after 48 hours. Twenty four hours after the removal of the topical induction patches, all animals in both groups were again examined for signs of skin irritation in the treated area. Moderate to marked irritation was apparent at the treated site on all test animals whilst minimal irritation was noted at the treated site on all control animals.

Fourteen days after the topical induction application, the fur was clipped from the back and flanks of all animals. Patches of Whatman No. 3 filter paper, 2cm x 2cm, were saturated with 25% w/v test substance in ethanol and placed on the left flank of all test and control animals. A patch soaked in ethanol alone was applied to the right flank of each animal. The patches were occluded and secured using the method previously described for topical application. After a contact period of 24 hours the patches and dressings were removed from all animals. Twenty four and 48 hours after removing the dressings the animals were examined and any dermal reaction scored.

Challenge controls:

No

Positive control substance(s):

yes

Remarks:

Hexyl cinnamic aldehyde at 30 % v/v.

Results and discussion

Positive control results:

Seven out of 10 animals in thepositive control test group gave positive responses to 30% HCA in acetone, resulting in a response incidence of 70%. None of the animals in the test group exhibited positive responses to acetone alone. None of the animals in the control group responded positively to 30% HCA or acetone alone. These results confirm that Hexyl cinnamic aldehyde is a Strong sensitiser under the conditions of this particular study and the test system is therefore considered to be validated.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25 % w/v

No. with + reactions:

5

Total no. in group:

20

Clinical observations:

No findings.

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25 % w/v. No with. + reactions: 5.0. Total no. in groups: 20.0. Clinical observations: No findings..

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25 % w/v.

No. with + reactions:

4

Total no. in group:

20

Clinical observations:

No findings.

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25 % w/v.. No with. + reactions: 4.0. Total no. in groups: 20.0. Clinical observations: No findings..

Any other information on results incl. tables

Following the challenge application, 5 animals in the test group exhibited positive responses to 25% w/v test substance in ethanol at the 24 hour examinations, giving a response incidence of 25%. However, only four animal had a positive response 48 hr after challenge. None of the test animals responded positively to ethanol alone. None of the animals in the control group responded positively to 25% test substance in ethanol or to ethanol alone at the 24 and 48 hour examinations, giving a response incidence of 0%.

Applicant's summary and conclusion

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: other: O.E.C.D. test guideline.

Conclusions:

It is considered that the test substance is a mild sensitiser in the guinea pig under the conditions of this Maximization study.

Executive summary:

The test substance, Bisphenol A, epichlorohydrin polymer, 2-methylimidazole condensate, was accessed for dermal

senitization potential in an O.E.C.D. test guideline 406 guinea pig Maximization study. At the 24 hr Challege observation five test animals responded with positive dermal reactions. Therefore, it is considered that the test substance is a mild sensitiser in the guinea pig under the conditions of this Maximization study.