Reaction mass of 2,6-di-tert-butylphenol and 2,4,6-tri-tert-butylphenol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November 5, 1900 to December 7, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The sensitivity and reliability of the experimental technique was not assessed by use of substances which are known to have mild-to-moderate skin sensitisation properties. However, it is considered that this deviation does not affect the outcome of the study. No GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

GLP compliance:

no

Type of study:

guinea pig maximisation test

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tri-tert-butylphenol; 2,6-di-tert-butylphenol

EC Number:

907-745-9

Molecular formula:

Not applicable - Multiconstituent substance

IUPAC Name:

2,4,6-tri-tert-butylphenol; 2,6-di-tert-butylphenol

Details on test material:

- Physical state: Clear pale yellow liquid on receipt, but solidified on storage at 0-5 ºC.
- Storage condition of test material: On its arrival the test substance was stored in the dark at ambient temperature. Following receipt of further information, the storage conditions were changed on 13th September 1990 to in the dark at between 0-5 ºC.

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Porcellus
- Age at study initiation: 7-11 weeks
- Weight at study initiation: males: 522-685 g; females: 386-598 g
- Housing: Animals were housed initially in single sex groups of ten animals. In the two-day period before the study began they were re-allocated to cages accommodating two or three animals. Hanging galvanised steel cages with wire-mesh floors were used. Each cage measured 53 cm x 35 cm x 29 cm. Sawdust-filled trays for excreta were placed beneath each cage and changed twice weekly.
- Diet (e.g. ad libitum): Pelleted diet (FD1, SQC, Special Diet Services Ltd.), ad libitum.
- Water (e.g. ad libitum): From public supply, ad libitum.
- Acclimation period: two weeks.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-23 ºC.
- Humidity (%): 30-70%
- Air changes (per hr): not documented.
- Photoperiod (hrs dark / hrs light): 12 hour day and 12 hour night.


IN-LIFE DATES: From November 5, 1900 to December 7, 1990

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

corn oil

Induction 2

Concentration / amount:

Induction - Intradermal injections (2% m/v in corn oil):
Test animals:
Anterior sites: 0.1 ml of Freunds Complete Adjuvant (FCA)
Middle sites: 0.1 ml of test material in vehicle
Posterior sites: 0.1 ml of test material in 50:50 FCA/vehicle

Control animals:
Anterior sites: 0.1 ml of FCA
Middle sites: 0.1 ml of vehicle
Posterior sites: 0.1 ml of 50:50 FCA/vehicle

Induction - topical:
0.3 ml of the undiluted test material.

Challenge:
0.1 ml of the indiluted test material.

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

corn oil

Challenge 2

Concentration / amount:

Induction - Intradermal injections (2% m/v in corn oil):
Test animals:
Anterior sites: 0.1 ml of Freunds Complete Adjuvant (FCA)
Middle sites: 0.1 ml of test material in vehicle
Posterior sites: 0.1 ml of test material in 50:50 FCA/vehicle

Control animals:
Anterior sites: 0.1 ml of FCA
Middle sites: 0.1 ml of vehicle
Posterior sites: 0.1 ml of 50:50 FCA/vehicle

Induction - topical:
0.3 ml of the undiluted test material.

Challenge:
0.1 ml of the indiluted test material.

No. of animals per dose:

Ten animals per sex.
Control group: five animals per sex.

Details on study design:

RANGE FINDING TESTS:
Two male and two female guinea pigs were closely shorn in the shoulder region using electric clippers followed by an electric razor. 0.1 ml doses of several dilution of the test material were injected intradermally on each side of the mid-line. The animals were examined on the following day to determine the maximum concentration that caused no more than moderate irritation. This was selected for use in the intradermal phase of induction.
The flank of each animal in further groups of two male and two female guinea pigs was closely shorn. 0.3 ml doses of several dilutions of the test material were absorbed onto 16 cm2 Whatman No. 3 filter paper patches. The patches were applied to skin on the shorn flanks, covered by occlusive tape and retained by an elastic adhesieve bandage for 24 hours. On the day after removal of the patches and bandages the dermal test sites were examined for signs of irritation. The undiluted test material was chosen for use at topical induction and challenge as it had proved to be non-irritant in the range-finding test.

MAIN STUDY
A. INDUCTION EXPOSURE
0.1 ml doses of several dilution of the test material were injected intradermally as described under the heading "concentration". One week after induction by intradermal injection, the same area of dorsal skin was shaven using electric clippers. A 16 cm2 patch of Whatman No. 3 filter paper was moistened with 0.3 ml of the undiluted test material and placed over the sites of intradermal injections. The patches were covered with occlusive tape and held in place by elastic adhesive bandage for 48 hours.


B. CHALLENGE EXPOSURE
Challenge was carried out three weeks after the intradermal phase of induction. Hair was removed from one flank of all test and control animals by clipping and shaving. A 4cm2 patch of Whatman No. 3 filter paper moistened with 0.1 ml of the undiluted test material, was placed on the shaven area, covered by occlusive tape and held in position by elastic adhesive bandage. After 24 hours the patches were removed and the challenges sites examined for any response.

Challenge controls:

Control animals were treated with the same formulation of test material that was applied to test group animals.

Positive control substance(s):

no

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

No. with + reactions:

1

Total no. in group:

19

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. No with. + reactions: 1.0. Total no. in groups: 19.0.

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

No. with + reactions:

0

Total no. in group:

19

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. No with. + reactions: 0.0. Total no. in groups: 19.0.

Any other information on results incl. tables

One of the nineteen test animals showed positive responses 24 hours after the removal of the challenge patches but none showed positive responses after 48 hours.

The death of one guinea pig after the topical induction phase of the study was attributed to constriction of the thorax by application of an overtight dressing.

Table 7.4.1: Summary of the Sensitisation Response after Challenge

	Sensitisation Response
	Hours
	24	48
Test animals	1/19	0/19
Control animals	0/10	0/10

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test substance did not exhibit a potential to produce dermal sensitisation in the guinea-pig.

Executive summary:

A range-finding test was performed to determine the appropriate concentrations that could be used for both intradermal and topical induction as well as topical challenge. The first induction phase involved six intradermal injections. These doses were comprised of pairs of injections of the test substance in corn oil, the test substance combined with Complete Freund´s Adjuvant and corn oil and the Adjuvant alone. A control group (ten animals) was maintained under the same environmental conditions and received injections of corn oil, corn oil combined with complete Freund´s Adjuvant and Adjuvant alone. The second phase of induction was conducted by topical application for a period of 48 hours. Three weeks later, a challenge dose of the test material was applied for 24 hours. Twenty-four and 48 hours after challenge patch removal, the animals were scored for a sensitisation response. The test substance did not exhibit a potential to produce dermal sensitisation in the guinea-pig.