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Administrative data

Description of key information

Tert-butyl acrylate is a potential skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
only small number of animals tested, no results of the control animals are presented
Qualifier:
no guideline followed
Principles of method if other than guideline:
According to Magnusson & Kligman (Allergic contact dermatitis in the guinea pig. Springfield, Illinois USA: Charles C. Thomas, 1970).
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
No LLNA study performed with tert-butyl acrylate is available performed for assessment. The Guinea Pig Maximization Test (GPMT) has been carried out as an animal test to predict human sensitization for over a decade and is recommended by international test guidelines such as OECD.
Specific details on test material used for the study:
- Name of test material (as cited in study report): t-butyl acrylate
- Analytical purity: > 99%
Species:
guinea pig
Strain:
Himalayan
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Himalayan white spotted outbred strain (Inst. for Biomed. Research, Fuellinsdorf, CH)
- Weight at study initiation: 350 - 450 g
- Housing: in pairs
- Diet (e.g. ad libitum): pellet diet
- Water (e.g. ad libitum): water containing Vitamin C

ENVIRONMENTAL CONDITIONS
not reported
Route:
intradermal
Vehicle:
arachis oil
Remarks:
or FCA
Concentration / amount:
0.5 M / 0.1 mL
Day(s)/duration:
day 0
Route:
epicutaneous, occlusive
Vehicle:
other: 80% ethanol
Concentration / amount:
3 M / 1 mL
Day(s)/duration:
day 7
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
not specified
Concentration / amount:
0.3 M/ 0.025 mL
Day(s)/duration:
day 21
Adequacy of challenge:
highest non-irritant concentration
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
not specified
Concentration / amount:
0.3 M/ 0.025 mL
Day(s)/duration:
day 35
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
10
Details on study design:
RANGE FINDING TESTS:
The maximum non-irritating concentration was determined after a single epidermal application and macroscopic readings after 24 and 48 h.

MAIN STUDY
A. INDUCTION EXPOSURE
Day 0
The 3 pairs of intradermal injections were made just within the boundaries of the 2 x 4 cm patch to be applied one week later, and were:
(1) 0.1 mL FCA alone (blended with an equal amount of water);
(2) 0.1 mL of the acrylate in ol. arachis (peanut oil);
(3) 0.1 mL of the acrylate in FCA (the acrylate was first suspended in FCA before an equal volume of water was added)

Day 0 control group
These animals received the same treatment but the acrylate was omitted.

Day 7
The test substance was dissolved in ethanol 80% in a concentration giving a slight to moderate irritation (as determined by the irritation test by open application) and was applied in an amount of 1 mL on a 2 X 4 cm Whatmann (3 mm) filter paper. The patch was covered by an impermeable adhesive tape.

Day 7 control group
The animals were exposed to the vehicle only in the same way as the experimental group.

- Concentrations: 0.5 M = ca. 64 mg/mL; 3 M = ca. 192 mg/mL


B. CHALLENGE EXPOSURE
Day 21: In both groups the right flank was shaved. The acrylates dissolved in pet., peanut oil or Aramek were applied in an amount of 0.025 mL in an aluminium chamber (Finn Chamber, Helsinki) or on Silver Patch (v.d Bend, Brielle). The highest concentration tested was the maximum nonirritating concentration (m.n.i.c.). The bandage was the same as used for the induction on day 7. It was left in place for 24 h. 3 h prior to the reading the flank was shaved. A second reading was made at 48 h.

Day 35: In both groups the left flank was shaved. The acrylates, in the same amount and vehicle as on day 21, were applied in an amount of 0.025 ml with a pipette on an area of 2 square cm, marked with a circular stamp. The test sites were left uncovered and read at 24 h and 48 h.
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.3 M
No. with + reactions:
4
Total no. in group:
10
Key result
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
0.3 M
No. with + reactions:
4
Total no. in group:
10
Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
only small number of animals tested, no results of the control animals are presented
Qualifier:
no guideline followed
Principles of method if other than guideline:
The study was conducted according to the method described by Klecak (1977) and Klecak and Geleick (1977).

Klecak (1977), Dermatoxicology and Pharmacology. Eds, Marzulli F N, Maibach H I. New York: John Wiley & Sons.
Klecak and Geleick (1977), Journal of the Society of Cosmetic Chemists, 28: 53.
GLP compliance:
not specified
Type of study:
Freund's complete adjuvant test
Justification for non-LLNA method:
No LLNA study performed with tert-butyl acrylate is available performed for assessment. The Freund's complete adjuvant test has been carried out as an animal test to predict human sensitization.
Specific details on test material used for the study:
- Name of test material (as cited in study report): t-butyl acrylate
- Analytical purity: > 99%
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Dunkin-Hartley outbred strain (Olac Ltd., Bicester, England)
- Weight at study initiation: 350 - 450 g
- Housing: in pairs
- Diet (e.g. ad libitum): pellet diet
- Water (e.g. ad libitum): water containing Vitamin C

ENVIRONMENTAL CONDITIONS
not reported
Route:
intradermal
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.5 M/ 0.1 mL
Day(s)/duration:
No. of exposures: 5 Exposure period: d0 - d9
No.:
#1
Route:
epicutaneous, open
Vehicle:
unchanged (no vehicle)
Concentration / amount:
undiluted / 0.025 mL
Day(s)/duration:
day 21
Adequacy of challenge:
highest non-irritant concentration
No.:
#2
Route:
epicutaneous, open
Vehicle:
unchanged (no vehicle)
Concentration / amount:
undiluted / 0.025 mL
Day(s)/duration:
day 35
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
8
Details on study design:
RANGE FINDING TESTS:
The maximum non-irritating concentration was determined after single epidermal application and macroscopic readings after 24 and 48 h.

MAIN STUDY
A. INDUCTION EXPOSURE
After the acrylate was emulsified in FCA, an equal volume of distilled water was added. On days 0, 2, 4, 7 and 9 intradermal injections with 0.1 ml of this emulsion were given in the shoulder area from the left to the right paw. Control animals were similarly treated with FCA, blended with an equal volume of distilled water.

- No. of exposures: 5
- Exposure period: d0 - d9
- Test groups: 1 with 8 animals, treated with 5* 0.1 mL of 0.5 M test substance emulsufied in FCA
- Control group: 1 with 4 to 6 animals, treated with 5* 0.1 mL of distilled water emulsufied in FCA
- Site: shoulder area
- Concentrations: 0.5 M = ca. 64 mg/mL


B. CHALLENGE EXPOSURE
All the animals were tested epicutaneously on day 21 (right flank) and day 35 (left flank). On day 21 right flank and on day 35 left flank of both groups were shaved. The test substance and the vehicle was applied in an amount of 0.025 ml with a pipette on an area of 2 square cm, marked with a circular stamp. The test sites were left uncovered and read at 24 h and 48 h.

- No. of exposures: 2
- Day(s) of challenge: d21, d35
- Test groups: 1 with 8 animals, treated with 2* 0.025 mL of undiluted test substance and two unspecified lower doses
- Control group: 1 with 4 to 6 animals, treated with 2* 0.025 mL of undiluted test substance and two unspecified lower doses
- Site: right flank (d21) and left flank (d35)
- Concentrations: undiluted
- Evaluation (hr after challenge): 24 and 48 h
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
undiluted
No. with + reactions:
4
Total no. in group:
8
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
undiluted
No. with + reactions:
4
Total no. in group:
8
Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
Please find the attached justification.
Reason / purpose for cross-reference:
read-across source
Key result
Parameter:
EC3
Value:
11.2
Remarks on result:
other: Result read-across source CAS No. 141-32-2. Correction for molecular weight is not required
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

Tert-butyl acrylate was tested for skin sensitization in the Freund's complete adjuvant test and the maximization test in guinea pigs (Van der Walle, 1982). In the Freund's complete adjuvant test, 5 intradermal inductions with 0.1 mL 0.5 M tert-butyl acrylate were performed within day 0 to 9 of the test. Challenge and re-challenge were done on day 21 and day 35, respectively, with 0.025 mL undiluted tert-butyl acrylate applied epicutanously. 4 of the 8 tested animals showed positive effects. The induction in the guinea pig maximization test was performed on day 0 with an intradermal injection followed by an epicutanous application on day 7 of 0.1 mL 0.5 M tert-butyl acrylate. On day 21 and 35 the challenge and rechallenge were performed with 0.025 mL undiluted test substance. 4 of the 10 tested animals showed sensitizing effects. In conclusion, tert-butyl acrylate showed a skin sensitizing effect in the guinea pig maximization test and the Freund's complete adjuvant test.

For derivation of an induction-specific DNEL for skin sensitization, an LLNA study with the structural analogue n- butyl acrylate was taken into account (BAMM 2006), in which an EC3 of 11.2% was found. Based on results obtained in the GPMT by the same laboratory, n-butyl acrylate and tert-butyl acrylate can be considered to be skin sensitizers of comparable potency confirming the validity of the read-across.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

There is no information available on the potential for tert-butyl acrylate to produce respiratory sensitisation in animals.

Justification for classification or non-classification

Based on the available data the test substance is classified as Skin Sens. 1B H317: May cause an allergic skin reaction in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and GHS classification (GHS UN rev.6, 2015).