Hexyl acrylate

Endpoint summary

Description of key information

Skin Sensitization-

Sensitizing to guinea pig (OECD 406 Guinea Pig Maximization Test)

Sensitizing to guinea pig (OECD 406 Freuds Complete Adjuvant Test)

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation, other

Remarks:

Human Repeat Insult Patch Test (HRIPT)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

TSCA 8E Notification

Principles of method if other than guideline:

The repeat patch testing was conducted in 7 human volunteers (mix of male and female). A solution of 6% 2-propenoic acid, hexyl ester in dimethyl phthalate was applied daily (duration not specified) over 10 sessions within the sensitization phase. The sensitization phase was followed by a challenge after which skin reactions were evaluated.
Intensity of skin reactions were graded on a three scale system as follows:
+1: redness, slight puffiness, scaliness, and occasional pinpoint sized papules or small group of such papules
+2: plus one response in addition to larger numbers of pinpoint or slightly larger vesicles with an increased degree of redness and puffiness and generally some slight peripheral extension of this redness
+3: plus two response in addition to marked redness, considerable puffiness and swelling, large vesicles both discrete and coalescent with oozing and crusting as the vesicle ruptures.

GLP compliance:

no

Remarks:

study predates GLP

Type of study:

patch test

Species:

other: human

Sex:

male/female

Reading:

1st reading

Group:

test chemical

Dose level:

6%

No. with + reactions:

7

Total no. in group:

7

One response at plus one: redness, some slight puffiness

Three responses at plus two: plus one reaction with larger numbers of pin point or slightly larger vesicles with an increased degree of puffiness and redness with generally slight peripheral extension of redness

Three responses at plus three: plus two manifestions in addition to marked redness, considerable puffiness, and swelling; large vesicles both discreet and coalescent with oozing and crusting as the vesicles rupture.

Interpretation of results:

study cannot be used for classification

Conclusions:

The skin sensitization potential of n-hexyl acrylate (6% in dimethyl phthalate) produced seven of seven positive responses in a human repeat patch irritation test. This finding supports the classification of n-hexyl acrylate as a skin sensitizer under the Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).

Executive summary:

N-hexyl acrylate (6% in dimethyl phthalate) was examined for its potential to be a skin sensitizer following repeat application in a human patch test; a positive response was noted in all seven participants. This finding supports the classification of n-hexyl acrylate as a skin sensitizer under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

Freud's Complete Adjuvant Test

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Principles of method if other than guideline:

Albino female guinea pigs (350-450 g) of the Dunkin Hartley outbred strain (Olac Ltd. Bicester England). Guinea pigs were housed in pairs and fed a pellet diet supplemented with water containing vitamin C ad libitum.

Skin irritation was assessed by a single open application of 0.025 mL to a 2 cm2 area of the clipped flank of 8 animals. A mixture of 2 parts Methyl Ethyl Ketone and one part peanut oil by volume was used as a solvent. Skin reactions were read after 24 and 48 hours and reported as maximum non-irritating concentration (m.n.i.c).

Induction- On days 0, 2, 4, 7, and 9 intradermal injections with 0.1 mL of test substance emulsified in FCA were given in the shoulder area.

Challenge- Animals were challenged epicutaneously onto the shaven right flank at day 21 and shaven left flank on day 35. N-hexyl acrylate was solubilized inFCA and 0.025 mL was applied to a 2 cm2 area.

Concentrations: Induction- 0.5 M of n-hexyl acrylate in FCA; Challenge- maximum non-irritating concentration, 1M

GLP compliance:

not specified

Type of study:

Freund's complete adjuvant test

Justification for non-LLNA method:

Study conducted prior to development of LLNA method.

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Polysciene Inc.
- Expiration date of the lot/batch: not specified

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Institute for Biomedical Research Fullinsdorf Switzerland
- Females (if applicable) nulliparous and non-pregnant: not specified
- Microbiological status of animals, when known: not specified
- Age at study initiation: not specified
- Weight at study initiation: 350 - 450 g
- Housing: pair housed
- Diet (e.g. ad libitum): Pellet diet
- Water (e.g. ad libitum): water supplmented with vitamin C
- Acclimation period: not specified

Route:

intradermal

Vehicle:

arachis oil

Concentration / amount:

Concentration: 0.5 M (8.6%); Amount: 0.1 mL n-hexyl acrylate in peanut oil

Day(s)/duration:

Day 0, 2, 4, 7 and 9

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, open

Vehicle:

arachis oil

Concentration / amount:

Concentration 1.0 M/ Amount applied 0.025 mL

Day(s)/duration:

Day 21/ 24 hours duration

Adequacy of challenge:

highest non-irritant concentration

No.:

#2

Route:

epicutaneous, open

Vehicle:

arachis oil

Concentration / amount:

Concentration 1.0 M/ Amount applied 0.025 mL

Day(s)/duration:

Day 35/ 24 hours duration

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Experimental: 8; Control: 4 - 6

Details on study design:

RANGE FINDING TESTS:
Skin irritation was assessed by a single open application of 0.025 mL to a 2 cm2 area of the clipped flank of 8 animals. A mixture of 2 parts Methyl Ethyl Ketone and one part peanut oil by volume was used as a solvent. Skin reactions were read after 24 and 48 hours and reported as maximum non-irritating concentration (m.n.i.c).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 5
- Exposure period: Day 0, 2, 4, 7 and 9
- Test groups: 0.1 mL intradermal injections of 0.5M of n-hexyl acrylate in FCA and equal volume of distilled water
- Control group: Same treatment as test group with acrylate omitted
- Site: 4X6 cm clipped area of shoulder
- Frequency of applications: single
- Duration: not applicable for injection
- Concentrations: 0.5 M

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: Day 21 and Day 35
- Test groups: Day 21: 0.025 mL of solubilized n-hexyl acrylate in FCA onto an uncovered area of 2 cm2; Day 35: 0.025 mL of solubilized n-hexyl acrylate in FCA onto an uncovered area of 2 cm2
- Control group: Same treatment as test group with acrylate omitted
- Site: Day 21: shaved right flank; Day 35: shaved left flank
- Concentrations: 1.0 M
- Evaluation (hr after challenge): 24 and 48 hours

Positive control substance(s):

no

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1.0 M

No. with + reactions:

8

Total no. in group:

8

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

test chemical

Dose level:

1.0 M

No. with + reactions:

8

Total no. in group:

8

Remarks on result:

positive indication of skin sensitisation

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The Freud's complete adjuvant test to assess the skin sensitization potential of n-hexyl acrylate (>99% purity) was positive. This finding warrants the classification of n-hexyl acrylate as a skin sensitizer Ctaegory 1B under the Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).

Executive summary:

N-hexyl Acrylate (>99% purity) was examined for its potential to be a skin sensitizer using the Freud's complete adjuvant test described by Klecak and Geleick. Following a preliminary irritation test, 8 guinea pigs were treated by intradermal injection (0.5M; 8.6% (w/v) vehicle/ n-hexyl acrylate) to induce sensitization. Guinea Pigs were challenged by topical application (1.0 M; 17.2% w/v n-hexyl acrylate in peanut oil). Indications of sensitization were noted in all eight animals. This finding warrants the classification of n-hexyl acrylate as a skin sensitizer Category 1B under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).

Reference 3

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

Freud's Complete Adjuvant Test

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Principles of method if other than guideline:

Albino female guinea pigs (350-450 g) of the Dunkin Hartley outbred strain (Olac Ltd. Bicester England). Guinea pigs were housed in pairs and fed a pellet diet supplemented with water containing vitamin C ad libitum.

Skin irritation was assessed by a single open application of 0.025 mL to a 2 cm2 area of the clipped flank of 8 animals. A mixture of 2 parts Methyl Ethyl Ketone and one part peanut oil by volume was used as a solvent. Skin reactions were read after 24 and 48 hours and reported as maximum non-irritating concentration (m.n.i.c).

Induction- On days 0, 2, 4, 7, and 9 intradermal injections with 0.1 mL of test substance emulsified in FCA were given in the shoulder area.

Challenge- Animals were challenged epicutaneously onto the shaven right flank at day 21 and shaven left flank on day 35. N-hexyl acrylate was solubilized inFCA and 0.025 mL was applied to a 2 cm2 area.

Concentrations: Induction- 0.5 M of n-hexyl acrylate in FCA; Challenge- maximum non-irritating concentration, 1M

GLP compliance:

not specified

Type of study:

Freund's complete adjuvant test

Justification for non-LLNA method:

Study conducted prior to development of LLNA method.

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Department of Dermatology in Nijmegen
- Expiration date of the lot/batch: not specified
- Purity: contains up to 16% hexanol

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Institute for Biomedical Research Fullinsdorf Switzerland
- Females (if applicable) nulliparous and non-pregnant: not specified
- Microbiological status of animals, when known: not specified
- Age at study initiation: not specified
- Weight at study initiation: 350 - 450 g
- Housing: pair housed
- Diet (e.g. ad libitum): Pellet diet
- Water (e.g. ad libitum): water supplmented with vitamin C
- Acclimation period: not specified

Route:

intradermal

Vehicle:

arachis oil

Concentration / amount:

Concentration: 0.5 M (8.6%); Amount: 0.1 mL n-hexyl acrylate in peanut oil

Day(s)/duration:

Day 0, 2, 4, 7 and 9

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, open

Vehicle:

arachis oil

Concentration / amount:

Concentration 1.0 M/ Amount applied 0.025 mL

Day(s)/duration:

Day 21/ 24 hours duration

Adequacy of challenge:

highest non-irritant concentration

No.:

#2

Route:

epicutaneous, open

Vehicle:

arachis oil

Concentration / amount:

Concentration 1.0 M/ Amount applied 0.025 mL

Day(s)/duration:

Day 35/ 24 hours duration

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Experimental: 6 - 10; Control: 4 - 6

Details on study design:

RANGE FINDING TESTS:
Skin irritation was assessed by a single open application of 0.025 mL to a 2 cm2 area of the clipped flank of 8 animals. A mixture of 2 parts Methyl Ethyl Ketone and one part peanut oil by volume was used as a solvent. Skin reactions were read after 24 and 48 hours and reported as maximum non-irritating concentration (m.n.i.c).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 5
- Exposure period: Day 0, 2, 4, 7 and 9
- Test groups: 0.1 mL intradermal injections of 0.5M of n-hexyl acrylate in FCA and equal volume of distilled water
- Control group: Same treatment as test group with acrylate omitted
- Site: 4X6 cm clipped area of shoulder
- Frequency of applications: single
- Duration: not applicable for injection
- Concentrations: 0.5 M

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: Day 21 and Day 35
- Test groups: Day 21: 0.025 mL of solubilized n-hexyl acrylate in FCA onto an uncovered area of 2 cm2; Day 35: 0.025 mL of solubilized n-hexyl acrylate in FCA onto an uncovered area of 2 cm2
- Control group:
- Site: Day 21: shaved right flank; Day 35: shaved left flank
- Concentrations: 1M
- Evaluation (hr after challenge): 24 and 48 hours

Positive control substance(s):

no

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1.0 M

No. with + reactions:

5

Total no. in group:

8

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

test chemical

Dose level:

1.0 M

No. with + reactions:

5

Total no. in group:

8

Remarks on result:

positive indication of skin sensitisation

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The Freud's complete adjuvant test to assess the skin sensitization potential of n-hexyl acrylate (containing up to 16% hexanol) was positive. This finding warrants the classification of n-hexyl acrylate as a skin sensitizer Ctaegory 1B under the Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).

Executive summary:

N-hexyl Acrylate (containing up to 16% hexanol) was examined for its potential to be a skin sensitizer using the Freud's complete adjuvant test described by Klecak and Geleick. Following a preliminary irritation test, 10 guinea pigs were treated by intradermal injection (0.5M; 8.6% (w/v) vehicle/ n-hexyl acrylate) to induce sensitization. Guinea Pigs were challenged by topical application (1.0 M; 17.2% w/v n-hexyl acrylate in peanut oil). Indications of sensitization were noted in five out of eight animals. This finding warrants the classification of n-hexyl acrylate as a skin sensitizer Category 1B under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Justification for classification or non-classification

The skin sensitizating potential for n-hexyl acrylate produced positive skin reactions in several in-vivo assays. This finding warrants the classification of n-hexyl acrylate as a skin sensitizer Category 1B under the Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP).