Estradiol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 1989 to December 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

1981

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

A valid Buehler test conducted comparable to guideline with acceptable restrictions is available, which is reliable with restrictions and adequate for classification and labelling purposes. Potency estimation is not mandatory when existing guideline and GLP conforming data are available, which were conducted before the new annex of the REACH Regulation entered into force. Moreover, only a minor indication for skin sensitisation was observed in this study, presumably rather based on the adhesive used in the patch and not due to the test substance, thus, no dose response information is needed. For this reason and for reasons of animal welfare no additional LLNA was conducted.

Test material

Test material information

Constituent 1

Reference substance name:

Estradiol

EC Number:

200-023-8

EC Name:

Estradiol

Cas Number:

50-28-2

Molecular formula:

C18H24O2

IUPAC Name:

estra-1,3,5(10)-triene-3,17-diol

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Wilmington, MA
- Diet (e.g. ad libitum): Ad libitum, Ralston Purina Guinea Pig Chow, Ralston Purina, St. Louis, MO
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Several days
- Indication of any skin lesions: No

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

water

Remarks:

Freund’s Adjuvant (1:1 commercial adjuvant with water) in an area over which the test article was immediately applied

Concentration / amount:

Freund’s Adjuvant (1:1 commercial adjuvant with water) in an area over which the test article was immediately applied

Day(s)/duration:

two injections with 0.1 mL of solution prior to topical application

Induction 2

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

5 cm² patch containing approx. 1.5 mg/patch

Day(s)/duration:

three application per week (Monday, Wednesday, and Friday)/ eight topical applications in total

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Remarks:

Estradiol TDD patch

Concentration / amount:

approx. 1.5 mg/patch

Day(s)/duration:

applied 14 days after last induction and with a duration of 24 h.

No. of animals per dose:

10

Details on study design:

RANGE FINDING TESTS: Due to the nature of the test article (an adhesive patch) and the
positive response of two animals during the challenge phase of the sensitization study, a guinea pig primary skin irritation study (5 animals) was conducted. The minimal irritation noted during the primary skin study suggests the erythema and edema noted during the challenge phase may have been due to irritation.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 8
- Exposure period: every second day
- Test groups: 1
- Control group: 1
- Site: dorsal shoulder girdle
- Frequency of applications: every second day (Monday, Wednesday, and Friday)
- Duration: 6h each
- Concentrations: approx. 1.5 mg/patch

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 14 days after last induction
- Exposure period: 24h
- Test groups: 1
- Control group: 1
- Site: dorsal shoulder girdle
- Concentrations: 1.5 mg/patch
- Evaluation (hr after challenge): 24 and 48 h

Shortly before the initial topical application two intradermal injections with Freund´s adjuvant were conducted in the same area at which the patches were placed.

Positive control substance(s):

yes

Remarks:

2,4-Dinitrochlorobenzene (DNCB)

Results and discussion

Positive control results:

Sensitization: 100%

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Remarks on result:

other: the performance of a negative control was not reported

Results 2

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Remarks on result:

other: the performance of a negative control was not reported

Results 3

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.05% DNCB

No. with + reactions:

10

Total no. in group:

10

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1.5 mg/patch

No. with + reactions:

1

Total no. in group:

10

Results 5

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

0.05% DNCB

No. with + reactions:

10

Total no. in group:

10

Results 6

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1.5 mg/patch

No. with + reactions:

2

Total no. in group:

10

Any other information on results incl. tables

Primary Skin Irritation test

	Irritation scores for abraded skin sites after removal
	One hour		Day 2
Animal Number	Erythema	Edema	Erythema	Edema
9G2929	1E	0	0	0
9G2934	0	0	0	0
9G2960	0	0	0	0
9G2965	1E	0	0	0
9G2930	0	0	0	0
Mean	0.4	0.0	0.0	0.0
Subtotal		0.4
Key	E= Epithelial Stripping

Results Test item

	One day		Two days
Animal Number	Erythema	Edema	Erythema	Edema
9G2907	0	0	0	0
9G2912	0	0	0	0
9G2917	0	0	0	0
9G2922	1E	0	0	0
9G2908	1	0	1	0
9G2913	0	0	0	0
9G2918	0	0	0	0
9G2923	0	0	0	0
9G2909	0	0	0	0
9G2914	0	0	0	0

Results Positive Control

	One day		Two days
Animal Number	Erythema	Edema	Erythema	Edema
9G2957	1	0	1	0
9G2962	1	0	0	0
9G2927	1	0	2	0
9G2932	1	1	1	0
9G2958	1	0	2	0
9G2963	2	0	2	1
9G2928	1	1	1	1
9G2933	1	0	1	0
9G2959	1	0	2	0
9G2964	2	0	2	0

 

 

 

 

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In the present test conducted similar to OECD 406 (1981); Bühler method, 10 Dunkin-Hartley guinea pigs were dermally exposed to Estradiol via TDD Patches containing approximately 1.5 mg Estradiol as indicated in the local tolerance test. The animals were exposed eight times every second day, prior to the initial application an intradermal application of Freund´s adjuvant was performed. Fourteen days after the last topical application the animals were again dermally exposed to the patches for 24h and the reactions were documented after 24h and 48h. Only slight Erythema nor Edema occurred after induction or challenge with the Estradiol TDD patches. Erythema was scored with 1 in two animals, in one animal the irritation was found to be due to the used adhesive of the patches causing epithelial stripping. In the second animal Erythema lasted until the second reading. According to CLP, EU GHS (Regulation (EC) No 1272/2008), a response of at least 30% of the test animals of an adjuvant type guinea pig test method for skin sensitisation is considered as positive. thus the substance does not meet the classification criteria for skin sensitization according to Regulation (EU) No. 1272/2008 (CLP) or the Globally Harmonized System for Classification and Labelling of Chemicals (GHS).

Executive summary:

In a dermal sensitisation study comparable to OECD guideline 406 (1981) with Estradiol TDD patches 10 young adult Hartley guinea pigs were tested using the method of Buehler.

Test concentrations were selected based on the results of an irritation screening study: the concentrations used in the pretest (approximately 1.5 mg/patch of the test substance) produced only a minor irritation in one animal. Thus, in the main study 1.5 mg of the test substance contained in the TDD patch were used for epicutaneous induction and challenge. Simultaneously to the initial topical induction an intradermal injection with Freund´s adjuvant was performed.

After challenge only minor visible changes of the treated skin sites were observed in the test group animals 24 and 48 h after patch removal (= grade 0.4).

The positive control DNCB produced a sensitisation rate of 100%.

The test material produced a response in 20% of animals. According to CLP, EU GHS (Regulation (EC) No 1272/2008), a response of at least 30% of the test animals of an adjuvant type guinea pig test method for skin sensitisation is considered as positive.

Estradiol is not a dermal sensitiser in this study.