SDBR

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 May 1999 - 28 May 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

17 July 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

30 September 1996

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study performed before alternative methods were available.

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

424-970-3

EC Name:

-

Cas Number:

166255-23-8

Molecular formula:

C16-H14-O3.C6-H16-O3-Si

IUPAC Name:

Triethoxysilylpropyl Dibenzoyl Resorcinol

Test material form:

solid

Details on test material:

Appearance: light yellow solid lumps (2-3 cm)

Specific details on test material used for the study:

Storage: at ambient temperature

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Remarks:

Crl:(HA)BR

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River, Germany
- Microbiological status of animals, when known: SPF
- Age at study initiation: circa 3 weeks
- Weight at study initiation: 223-457g
- Housing: maximal 10 animals per cage
- Diet: standard laboratory diet (SDS Special Diets services, Whitham, England), ad libitum
- Water: tap water, ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3
- Humidity (%): 55-79
- Air changes (per hr): ca. 10
- Photoperiod (hrs dark / hrs light): 12/12

- IN-LIFE DATES: From: 4 May 1999 To: 28 May 1999

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

maize oil

Concentration / amount:

3%

Induction 2

Route:

epicutaneous, open

Vehicle:

maize oil

Concentration / amount:

30% (pretreatment with 10% SLS)

Challenge

Challenge 1

No.:

#1

Route:

epicutaneous, semiocclusive

Vehicle:

maize oil

Concentration / amount:

10%

Day(s)/duration:

14 days after last induction

Challenge 2

No.:

#2

Route:

epicutaneous, semiocclusive

Vehicle:

maize oil

Concentration / amount:

30%

Day(s)/duration:

14 days after last induction

No. of animals per dose:

Number of animals in test group: 10
Number of animals in negative control group: 5

Details on study design:

RANGE FINDING TESTS:
The response to intradermal treatment was examined in animals, that were treated with 3%, 1%, 0.3% and 0.1% of SDBR in maize oil. A sufficiently large area of the flanks was clipped free from hair and amounts of 0.1 mL of the concentrations were applied by intradermal injection.
The irritation response to topical treatment of various concentrations of the test item (1%, 3%, 10% and 30%) was examined in 2 other guinea pigs. The test item was brought into contact with the clipped skin and covered with a piece of hypoallergenic paper. The dressing was left in place for ca. 24 hours. Circa 24 and 48 hours after removal of the dressing, the skin was examined.

MAIN STUDY
A. INDUCTION EXPOSURE
Induction was achieved by an intradermal injection and one week later by topical application over the injection site.
For the intradermal injections an area of about 24cm2 of dorsal skin in the scapular region was clipped free from hair. Pairs of intradermal injections (0.1 mL each) were made simultaneously.
The following preparations were injected:
Test animals: two injections with Freund's Complete Adjuvant (FCA) and saline (1:1), two injections with SDBR solution and two injections with SDBR solution in FCA/diluent (1:1);
Control animals: two injections with FCA/ saline (1:1), two injections with the diluent and two injections with FCA/diluent (1:1).
Skin readings were made at ca. 24 hours after the treatment.

Six days after the intradermal injections, the dorsal skin in the scapular region of all test and control animals was closely clipped again, and subsequently treated with a 10% dilution of sodium lauryl sulfate in vaseline (open application). On the following day, the induction by topical application was made in this region. A circa 2x4 cm patch of Whatman No.3 MM filter was loaded with the selected concentration of the test substance. The loaded patch was placed over the sites of the intradermal injections and was secured in place for ca. 48 hours. The control animals were similarly treated with the vehicle only. Skin readings were made directly after removal of the patches.

B. CHALLENGE EXPOSURE
The topical challenge was carried out 14 days after the topical induction. An area of ca. 5x5 cm on the right and left flank of each test and control animal was clipped free from hair. Patches were loaded with the two test concentrations selected or with the vehicle alone. Subsequently, two patches loaded with the two test concentrations (10% and 30%) were placed on the clipped area of the right flank of each test and control animal and the patch loaded with the vehicle on the left flank. The patches were covered with Leukopor bandage, and held in place by Tensoplast for ca. 24 hours. Skin readings were made at ca. 24 and 48 hours after removal of the patches.

Positive control substance(s):

yes

Remarks:

A study with a positive control substance was performed in April 1999 (not as a part of this study).

Results and discussion

Positive control results:

The sensitivity of the test system was checked by means of a positive control study with formaldehyde (37%). This study was performed in April 1999 (results included in the study report).

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 %

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 2

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

30 %

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 3

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 5

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

5 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 6

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

5 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Any other information on results incl. tables

Preliminary test:

The degree of irritation observed after intradermal treatment with the 3% test concentration was considered suitable for intradermal treatment during unduction phase. A concentration higher than 3 % could not be injected by syringe.

A 30% concenctration was considered acceptable for topical treatment during the induction and challenge phase. A concentration above 30% was considered not feasible, as it was expected to form a very tough and dry paste. Since the 30% test concentration was not irritating, the induction site was pretretaed with 10% SLS in vaseline. In addition a 10% test concentration was also examined during challenge, because of an incidental slight erythema observed during the preliminary test.

Signs of irritation during induction:
After topical application of the vehicle alone, slight erythema was generally observed in the controls. After the 48-hours topical application of the selected test
concentration, slight erythema was also generally observed in the test animals.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results of a guinea pig maximization test performed according to OECD/EC guidelines and under GLP principles, SDBR is concluded not to be a skin sensitizer.