4-ethenylphenyl acetate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09.07.-09.08.1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The guinea-pig is a good animal model for predicting delayed contact hypersensitivity in man.

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

434-600-2

EC Name:

-

Cas Number:

2628-16-2

Molecular formula:

CH3CO2C6H4CH=CH2

IUPAC Name:

4-ethenylphenyl acetate

Test material form:

liquid

Specific details on test material used for the study:

C-908 (Acetoxystyrene monomer - ASM), purity > 99%

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

Test Animals:
- Body weight 217 - 302 g at arrival
- bred under hygenic conditions

Animal husbandry:
- no more than five guinea pigs per stainless steel cage, measuring 55 x 60 x 23 cm with grid floors and tops
- located in a limited access building
- approx. 15 aire changes per hour
- temperature: 18°C (range 15 - 23°C)
- humidity: 55% r.h. (range 40 - 70% r.h.)
- artificial light with a 12 h light / dark cycle
- diet: petteted guinea-pig diet ad libitum
- water: free access to tap water

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

olive oil

Concentration / amount:

3% v/v

Day(s)/duration:

on day 1

Adequacy of induction:

other: well toleated dose as tested in a screening test

Induction 2

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

0.6 mL test substance

Day(s)/duration:

on day 8 for 48 hours

Adequacy of induction:

other: well toleated dose as tested in a screening test

Challenge

Challenge 1

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

neat substance

Day(s)/duration:

on day 22 for 24 hours

Adequacy of challenge:

other: well toleated dose as tested in a screening test

Challenge 2

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

olive oil

Concentration / amount:

30% v/v of the test substance

Day(s)/duration:

on day 22 for 24 hours

Adequacy of challenge:

other: well toleated dose as tested in a screening test

No. of animals per dose:

10 animals per sex per dose

Details on study design:

Preparation of the animals:
- examnation on delivery and needed to be in a good state of health
- weight assessment: animals weighed at arrival
- identification: tattooed ear-marks
- acclimatisation: 10 days
- application site: 4 x 6 cmoverlying the scapulae wsa clipped free of hair before treatment
- body weight: 318 - 439 g at the before treatment

Preparation of test material:
- fresh doses were prepared before administration
- test material in olive oil, Freunds Complete Adjuvant or olive oil and Freunds Complete Adjuvant

A primary skin irritation test has been performed in order to determine the concentration limits for the main study

Control group for the main study:
- treated identically to the test group (induction and challenge) except that during induction the test material was replaced by vehicle

Primary induction:
- intradermal injection at day 1
- three pairs of injections (0.1 mL) (see table below)
- dermal test site 4 x 2 cm
- dermal responses assessed after 24 and 48 h after injection

Secondary induction:
- clipped dorsa treated with 10% w/v sodium lauryl sulphate in petrolatum on day 7
- occluded topical application of 0.6 mL (test item or olive oil) on a 4 x 2.5 cm absorbent patch on day 8 for 48 hours
- dermal responses assessed after 24 and 48 h after removal of occlussive dressing

Challenge procedure:
- clipped area of 5 x 5 cm on both flanks
- left side: topical application of 0.03 mL of olive oil on day 22
- right side: topical application of 0.03 mL of test item to one site and 0.03 mL 30% test item v/v in olive oil to a second site
- covered by occlusive dressing for 24 h

Assessment of the challenge reactions:
- examined approx. 24 and 48 h, after removal of the occlusive dressing
- presence or absence of erythema and swellings were assessed and the degree of reaction scored on a five point scale (see table below)

Body weight:
- recorded a weekly intevalls

Mortality and termination procedure:
- dead animals were subjected to necropsy
- all surviving animals were sacrificed at termination of the study

Challenge controls:

treated identically to the test group (induction and challenge) except that during induction the test material was replaced by vehicle

Positive control substance(s):

no

Results and discussion

Positive control results:

not applicable

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100% test item

No. with + reactions:

10

Total no. in group:

19

Remarks on result:

positive indication of skin sensitisation

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100% test item

No. with + reactions:

18

Total no. in group:

19

Remarks on result:

positive indication of skin sensitisation

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

30% v/v test item in olive oil

No. with + reactions:

3

Total no. in group:

19

Remarks on result:

positive indication of skin sensitisation

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30% v/v test item in olive oil

No. with + reactions:

12

Total no. in group:

19

Remarks on result:

positive indication of skin sensitisation

Any other information on results incl. tables

Bodyweight and general health

All surviving animals generaly made expected bodyweight gains during the study.

One test group animal was found dead on day 11. This was considered as incidental and not related to the test item.

Incidence of significant dermal response to challenge with olive oil, neat test item and 30% v/v test item in olive oil

Group	Treatment	No. of animals	Incidence of significant responses^+		Total responders
			24 hours	48 hours
Control	Olive oil	20	1	5	6
Test	Olive oil	19*	2	4	4
Control	test item (as supplied)	20	6	5	7
Test	test item (as supplied)	19*	10	18	18
Control	30% v/v test item in olive oil	20	0	2	2
Test	30% v/v test item in olive oil	19*	3	12	13

⁺ slight erythema or a marked response (grade 1 or above)

* one male animal was found dead on day 11

Applicant's summary and conclusion

Interpretation of results:

other: Skin sensitizer according to criteria as determined in the GPMT.

Conclusions:

In conclusion, the response in pretreated animals clearly indicates that acetoxystyrene is a potent skin sensitizer in guinea pigs by the maximization procedure and caused delayed contact hypersensitivity.

Executive summary:

The present skin sensitization study was performed in guinea-pigs by the maximization procedure. The test was performed according to OECD TG 406 and in compliance to GLP. Ten males and ten females were used for the control groups, the olive oil, the neat test item and the 30% v/v test item in olive oil group. The animals were intradermally induced at day one (primary induction) and dermally induced (second induction) at day 8 for 48 hours under occlusion. The animals were challenged topically on day 22 and examined after approx. 24 and 48 h.

The incidence of significant dermal responses (slight erythema or more marked reaction) to challenge with the neat test item or 30% v/v test item in olive oil was considerably greater in test group animals than in the control animals. Altough the olive oil caused a slight irritant effect per se the severity of the response in the test group animals was far more severe than that of the control animals and was considered to be consistent with an allergic reaction.

Forty-eight hours after challenge exposure to neat acetoxystyrene, the maximum number of responding animals was 18 out of the 19 test animals. This response classifies the test material as an extreme sensitizer using the classification scheme proposed by Magnusson and Kligman. A positive response to the challenge dose was also observed in 12 of 19 animals with a 30% preparation of the test material in olive oil.

In conclusion, the test material itself produced some skin irritation in control animals. However, the response in pretreated animals clearly indicates that acetoxystyrene is a potent skin sensitizer in guinea pigs by the maximization procedure and caused delayed contact hypersensitivity in guinea-pigs.