Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

adapted July 17, 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Valid in vivo data with guinea pigs are available therefore no further needs to be performed

Test material

Test material information

Constituent 1

Reference substance name:

Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

EC Number:

255-392-8

EC Name:

Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

Cas Number:

41484-35-9

Molecular formula:

C38H58O6S

IUPAC Name:

2-[(2-{[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl]oxy}ethyl)sulfanyl]ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate

Details on test material:

- Physical state: solid, white
- Analytical purity: > 95%

- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:

guinea pig

Strain:

other: Pirbright White Strain (Tif: DHP)

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: CIBA-GEIGY Limited, Animal Production, 4332 Stein / Switzerland
- Weight at study initiation: 303 to 400 g
- Housing: individually in Macrolon cages (Type 3)
- Diet: ad libitum standard guinea pig pellets - NAFAG No. 845, Gossau SG
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 to 70
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

arachis oil

Concentration / amount:

5%

Induction 2

Route:

epicutaneous, occlusive

Vehicle:

other: vaseline

Concentration / amount:

50%

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: vaseline

Concentration / amount:

50%

No. of animals per dose:

10 females and 10 males (test group)
5 females and 5 males (control group)

Details on study design:

RANGE FINDING TESTS:
The concentration for the intradermal injections was selected on account of the solubility of the test article in standard vehicles and its local and systemic tolerability in a pretest. The following concentrations of test article have been prepared for intradermal injection: 5 % in Oleum arachidis. Since 5% test substance in Oleum arachidis could be injected and was well tolerated, this concentration was used for the intradermal induction. The concentrations for the epidermal applications were selected on account of the primary irritation potential of the test article. The following concentrations of test substance have been examined on separate animals for the determination of the maximum subirritant concentration: 10, 20, 30, and 50% in vaseline. The tested concentrations did not induce erythema reactions, therefore 50% test article was selected for epidermal induction and challenge.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal and epicutaneous, respectively)
- Exposure period: single injection (intradermal) and 48h (epicutaneous)
- Test groups:
Interdermal (3 pairs of injections, 0.1 ml each):
Injection 1: adjuvant/saline mixture 1:1 (v/v)
Injection 2: test article in Oleum arachidis (w/v)
Injection 3: test article in the adjuvant/saline mixture (w/v)
Epicutaneous: test substance in vaseline (w/w), occluded
- Control group: was treated with adjuvant and the vehicle during the induction period
- Site: neck (intradermal and epicutaneous)
- Concentrations: intradermal: 5%, epicutaneous: 50%

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: week 5
- Exposure period: 24 hours
- Test groups: test substance and vehicle only
- Control group: test substance and vehicle only
- Site: flank
- Concentrations: 50%
- Evaluation (hr after challenge): 24 and 48 hours

OTHER:
Epidermal induction: No skin irritation was observed in the pretest. Therefore the application site was pretreated with 10% sodium-laurylsulfate (open application) 24 hours prior to the epidermal induction application.

Positive control substance(s):

yes

Remarks:

Potassiumdichromate

Results and discussion

Positive control results:

The following concentrations of the reference compound and vehicles were used:
Intradermal induction: Concentration of compound: 0.2%, Vehicle: physiological saline
Epidermal induction: Concentration of compound: 5%, Vehicle: vaseline
Epidermal challenge: Concentration of compound: 1%, Vehicle: vaseline

Result: 90% of the tested animals in the test group showed positive reactions whereas 0% positive results were found in control group.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

5%

No. with + reactions:

0

Total no. in group:

10

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

5%

No. with + reactions:

0

Total no. in group:

10

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5%

No. with + reactions:

0

Total no. in group:

20

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5%

No. with + reactions:

0

Total no. in group:

20

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions employed, none of the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings. The test substance is therefore classified as not sensitising to skin in albino guinea pigs according to EU and GHS classification criteria.

Executive summary:

The test substance was investigated for its sensitizing potential in a GLP-compliant Maximization test according to OECD guideline 406. Pirbright White guinea pigs received intradermal induction treatments with 5% in oleum arachidis and one epicutanous induction treatment with 50% in vaseline. For intradermal induction, three pairs of injections (adjuvant/saline; test item in vehicle; test item in adjuvant/saline) were given. Epidermal challenge was performed by occlusive application for 24 h two weeks later (50% in vaseline). The control group was exposed to vehicle only during this procedure. No skin reactions were observed either for control or test group animals and therefore no animal was sensitized by the test article under the experimental conditions employed. The sensitivity of the strain is controlled every six month with p - phenylenediamine. In conclusion, the test substance is not considered to be a skin sensitizer in albino guinea pigs.