Hexyl acrylate

Endpoint summary

Description of key information

In-Vivo Skin Irritation- Irritating to Rabbit Skin (No guideline followed, Klimisch 2)

In-Vivo Skin Irritation- Weakly Irritating to Rabbit Skin (No guideline followed, Klimisch 4)

(Q)SAR- Irritating to skin >> (meth)acrylic acid ester and carboxylic acid ester

 

In-Vitro Eye Irritation- Irritating to Rabbit Eye (No guideline followed, Klimisch 2)

(Q)SAR- Irritating/Corrosive to eyes >> extrapolation to skin irritation

 

See field "Additional information" for weight of evidence evaluation of skin irritation/corrosion and eye irritation/serious eye damage potential.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation / corrosion, other

Remarks:

QSAR

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
OASIS TIMES v.2.27.17

2. MODEL (incl. version number)
Skin irritation corrosion v.04 June 2015

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCCCOC(=O)C=C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

- Software tool(s) used including version: OASIS TIMES v.2.27.17
- Model(s) used: Skin irritation corrosion v.04 June 2015
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Specific details on test material used for the study:

SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCCCOC(=O)C=C

Irritation parameter:

other: QSAR Prediction

Remarks on result:

other: Irritating to skin >> (Meth)Acrylic acid esters///Irritating to skin >> Carboxylic acid esters

Interpretation of results:

other: Category 2 (irritant) based on QSAR Prediction

Conclusions:

N-hexyl Acrylate is predicted to be skin irritating based on the presence of two structural alerts: (meth) Acrylic acid esters and Carboxylic acid esters.

Executive summary:

The skin irritating potential of N-hexyl acrylate (SMILES: CCCCCCOC(=O)C=C) was predicted using the TIMES SS QSAR Skin Irritation/Corrosion (v.04 June 2015) model. N-hexyl acrylate is predicted to be skin irritating based on the presence of two structural alerts: (meth) Acrylic acid esters and Carboxylic acid esters. The final result is considered adequate for the regulatory purpose as it allows discrimination between skin irritation and corrosion and the chemical substance falls completely within the applicability domain. This data is considered supporting information considered within a weight of evidence approach.

Reference 2

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Primary skin irritation on rabbits is recorded in a 10-grade ordinal series and is based upon the severest reaction that develops on the clipped skin of each of five New Zealand albino rabbits within 24 hours of the uncovered application of 0.01 mL of undiluted sample.

GLP compliance:

no

Remarks:

Study predates GLP

Specific details on test material used for the study:

Specific details not provided

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Details on test animals and environmental conditions not provided

Type of coverage:

open

Preparation of test site:

clipped

Vehicle:

not specified

Remarks:

General method indicates vehicle could be water, propylene glycol or acetone

Controls:

not required

Amount / concentration applied:

0.01 mL of undiluted sample or solutions in water, propylene glycol, or acetone.

Duration of treatment / exposure:

Duration of treatment/exposure: 24 h

Observation period:

Observation period: 24 h

Number of animals:

5 Albino Rabbits

Details on study design:

Chemical was applied in 0.01 ml, amounts to clipped, uncovered intact skin of 5 rabbits either undiluted or in progressive dilutions of 10, 1, 0.1, and 0.01% in solvent. Ten grades are recognized based on appearance of moderate or marked capillary, erythema, edema or necrosis within 24 hours.

Grade 1 indicates no irritation and Grade 2 the least visible capillary injection from the undiluted chemical. Grade 6 indicates necrosis when undiluted and Grade 10 indicates necrosis from a 0.01% solution.

Irritation parameter:

other: Irritation Grade based on scale in Carpenter et al. (1946)

Basis:

mean

Time point:

24 h

Score:

5

Reversibility:

not specified

Remarks on result:

positive indication of irritation

Irritant / corrosive response data:

Irritation grade 6.0 indicates necrosis when undiluted, therefore a score of grade 5.0 is indicative of irritation if not minimal necrosis.

Interpretation of results:

other: Category 2 (irritant) based on physiologic description

Conclusions:

Based on the irritation score of Grade 5.0, which corresponds to Necrosis, n-hexyl acrylate is considered irritating to the skin.

Executive summary:

N-hexyl acrylate produced a skin irritation or corrosion score of Grade 5.0 (irritation/minimal necrosis) following 24 hour open application of 0.1 mL to 5 New Zeland White rabbits. While direct comparison of the grading shceme used in this study to current GHS criteria is not possible, this finding, evaluated within a weight of evidence approach, supports classification of N-hexyl Acrylate as a Category 2 Skin Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).

Reference 3

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Principles of method if other than guideline:

Chemical was applied in 0.32 ml amounts to clipped intact skin of 9 rabbits. Chemical was maintained in contact with skin by occlusive dressing for 24 hours. Irritation was assessed by Draize scores immediately and at 24 and 48 hours after patch removal.

GLP compliance:

not specified

Remarks:

Study published in literature, GLP status not specified

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

-Source: Japan Laboratory Animals Inc.
-Age at study initiation: 17 weeks
-Weight at study initiation: 90-120 g
-Diet: RC4 solid laboratory chow
-Water: ad-libitum

ENVIRONMENTAL CONDITIONS
-Animals were housed in individual cages in controlled temperature (23±2°C), relative humidity (55±10%), illumination (12 hr light/12hr dark cycle).

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

Test Material
-Amount(s) applied (volume or weight with unit): 0.32 ml
-Concentrations: 2300 ppm, 23000 ppm, 230000 ppm

Duration of treatment / exposure:

Duration of treatment/exposure: 24 h

Observation period:

Dermal reactions were evaluated according to the Draize criteria immediately, and at 24 and 48 hours after removal.

Number of animals:

Number of animals: 9 males

Details on study design:

Details on study design: Chemical was applied in 0.32 ml amounts to 20x20 mm lint cloth patch placed on clipped intact skin of 9 rabbits at three different concentrations (EC50, one tenth EC50, and 10 times the EC50 for cytotoxicity determined by MTT in a three-dimensional cultured human dermis model). The patches were wrapped with a poly-chlorovinylidene film and a moisture impervious adhesive tape. Patches were removed after 24 hours, and dermal reactions were evaluated according to the Draize criteria immediately, and at 24 and 48 hours after removal. The primary dermal irritation index (PDII) was calculated by dividing the sum of the mean Draize scores immediately and 48 hours by 2. From the PDII obtained at three different concentrations, a lowest erythema dose (concentration estimated to give PDII of 1.00) was calculated.

Irritation parameter:

other: lowest dose (ppm) which is estimated to give primary dermal irritation index (PDII) of 1.00

Basis:

mean

Score:

ca. 29 000

Remarks on result:

probability of weak irritation

Irritant / corrosive response data:

Weak dermal irritating activity

Interpretation of results:

study cannot be used for classification

Conclusions:

Although the individual Driaze and raw primary dermal irritation index scores were not given, N-hexyl acrylate was described as producing weak dermal irritating activity in rabbits and weak cytotoxicity in an in-vitro dermal model.

Executive summary:

N-hexyl acrylate produced evidence of weak skin irritation following 24 hour occlusive application of 0.32 mL to 9 New Zealand White Rabbits. As individual animal Draize scores were not provided, comparison to GHS criteria is not possible. However, this finding, evaluated within a weight of evidence approach, supports classification of N-hexyl acrylate as a Category 2 Skin Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation, other

Remarks:

QSAR Prediction

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
OASIS TIMES v.2.27.17

2. MODEL (incl. version number)
Eye irritation v.04 June 2015

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCCOC(=O)C=C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

- Software tool(s) used including version: OASIS TIMES v.2.27.17
- Model(s) used: Eye irritation v.04 June 2015
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Specific details on test material used for the study:

SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCCCOC(=O)C=C

Irritation parameter:

other: QSAR Prediction

Remarks on result:

other: Irritating/Corrosive to eye >> Extrapolation from skin to eye irritation

Interpretation of results:

other: Category 2 (irritant) based on QSAR Prediction

Conclusions:

N-hexyl Acrylate is predicted to be an eye corrosive/irritant based on an extrapolation step looking for skin irritation alerts. As this substance is indicated as causing skin irritation/corrosion, it is assumed that the substance could also damage the eye. There is no available classification criteria for QSARs and therefore this study should only be used as supporting information within a weight of evidence.

Reference 2

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Eye injury in rabbits is recorded in a 10 grade ordinal series and is based upon the degree of corneal necrosis that results from single instillation of 0.5 ml undiluted test substance into conjunctival sac of 5 rabbits. Read immediately unstained and after fluoroscein at 24 hours, with ten grades recognized

GLP compliance:

no

Remarks:

Study predates GLP

Species:

rabbit

Strain:

not specified

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source:
- Age at study initiation:
- Weight at study initiation:
- Housing:
- Diet (e.g. ad libitum):
- Water (e.g. ad libitum):
- Acclimation period:

ENVIRONMENTAL CONDITIONS
- Temperature (°C):
- Humidity (%):
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light):

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

Duration of treatment: 24 h

Number of animals or in vitro replicates:

5 Rabbits

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no washing
- Time after start of exposure:

SCORING SYSTEM: Grade 1 indicates at most a very small areas of necrosis resulting from 0.5 mL undiluted chemical in the eye. Grade 5 indicates a severe burn from 0.005 mL undiluted and Grade 10 indicates a severe burn from 0.5 mL of a 1% solution in water or propylene glycol.

TOOL USED TO ASSESS SCORE: fluorescein

Irritation parameter:

other: Irritation grade based on Carpenter et al. (1946)

Basis:

mean

Time point:

24 h

Score:

1

Reversibility:

not specified

Remarks on result:

positive indication of irritation

Irritant / corrosive response data:

Grade 1.0 corresponds to Necrosis on less than 5% of cornea

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

Based on the irritation score of Grade 1.0, which corresponds to Necrosis on less than 5% of cornea, n-hexyl acrylate is considered irritating to the eye.

Executive summary:

N-hexyl Acrylate produced evidence of eye irritation in an in-vivo rabbit assay. This finding supports classification of N-hexyl Acrylate as a Category 2 Eye Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

A weight of evidence approach was applied to determine the classification for skin and eye irritation potential of n-hexyl acrylate using the framework presented in OECD guidance document No. 203.

 

Module 1. Existing human data:

Not available

 

Module 2. In-vivo study:

N-hexyl acrylate produced evidence of skin irritation in two in-vivo rabbit assays. An in vivo skin irritation study resulted in an irritation score of Grade 5.0 following open application for 24 hours, which corresponded to irritation if not minimal necrosis (Smyth et al. 1969). This study was given a Klimisch score of 2 (Reliable with restrictions) as the study predates GLP and the exposure time frame was longer than specified in the OECD TG (24 hours). In another in-vivo study N-hexyl acrylate was described as producing weak dermal irritating activity in rabbits (Tokumura et al. 2010). This study was given a Klimisch score of 4 as documentation of the methods and results were insufficient to allow assessment or reliability. Both pieces of data are consistent with the (Q)SAR prediction of irritation/corrosion as well as the Annex VI harmonized classification for n-hexyl acrylate as a Category 2 Skin Irritant (Index No. 607-233-00-2).

 

N-hexyl acrylate produced evidence of eye irritation in an in-vivo rabbit assay. Based on the irritation score of Grade 1.0, which corresponds to necrosis on less than 5% of cornea, n-hexyl acrylate is considered irritating to the eye. This study was given a Klimisch score of 2 (Reliable with restrictions). This data is consistent with the (Q)SAR prediction of irritation/corrosion to the eye as well as the Annex VI harmonized classification for n-hexyl acrylate as a Category 2 Eye Irritant (Index No. 607-233-00-2). 

 

Module 3. In-vitro corrosion data:

An in vitro irritation/corrosion study was not conducted because adequate data from in vivo skin and eye irritation studies are available.

 

Module 4.In-vitro irritation data:

An in vitro irritation/corrosion study was not conducted because adequate data from in vivo skin and eye irritation studies are available.

 

Module 5. Other in-vivo and in-vitro data

Not available

 

Module 6. Physico-chemical Properties:

Test data on the pH of n-hexyl acrylate is not available, but is not expected to fall into the extremes (pH <2 or >11).

 

Module 7. Non-testing methods ((Q)SAR, grouping, bridging & additivity approaches):

A QSAR prediction for skin irritation/corrosion was generated using the Skin Irritation v.04 June 2015 model of the OASIS TIMES v.2.27.17 software. N-hexyl acrylate is predicted to be a skin irritant based on the presence of acrylic acid ester and carboxylic acid ester structural fragment. The QSAR prediction for skin irritation was given a Klimisch score of 2 (reliable with restrictions) as the results are derived from a valid QSAR model with adequate and reliable documentation/justification and falling completely within its applicability domain. The QSAR model for skin irritation was considered capable of predicting irritation to the skin. This result is consistent with the in-vivo irritation data as well as the Annex VI harmonized classification for n-hexyl acrylate as a Category 2 Skin Irritant (Index No. 607-233-00-2).

 

A QSAR prediction for eye irritation/corrosion was generated using the Eye Irritation v.04 June 2015 model of the OASIS TIMES v.2.27.17 software. N-hexyl Acrylate is predicted to be an eye irritant/corrosive based on an extrapolation step looking for skin irritation alerts. As this substance is indicated as causing skin irritation, it is assumed that the substance could also damage the eye. The QSAR prediction for eye irritation was given a Klimisch score of 2 (reliable with restrictions) as the results are derived from a valid QSAR model with adequate and reliable documentation/justification and falling completely within its applicability domain. The QSAR model for eye irritation was considered capable of predicting irritation/corrosion to the eye. This data is consistent with the in-vivo irritation data and although the QSAR prediction cannot discriminate between eye irritation and corrosion, it supports the Annex VI harmonized classification for n-hexyl acrylate as a Category 2 Skin Irritant (Index No. 607-233-00-2).

 

Overall Conclusion:

The availability of adequate in-vivo irritation data was sufficient to negate the need for in vitro studies.The findings of both the QSAR predictions and in vivo skin irritation studies support application of the Annex VI harmonized classification of N-hexyl acrylate (Index No. 607-233-00-2) as a Category 2 Skin Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).

 

As this substance is indicated as causing skin irritation/corrosion, it is assumed that the substance could also damage the eye. Additionally, an in vivo rabbit assay produced evidence of eye irritation. These findings support application of the Annex VI harmonized classification of N-hexyl Acrylate (Index No. 607-233-00-2) as a Category 2 Eye Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).

Justification for classification or non-classification

A weight of evidence evaluation was conducted to determine if classification as an Skin Corrosive/Irritant was warranted. N-hexyl acrylate produced evidence of skin irritation in two in-vivo assays, which were supported by a positive QSAR prediction of skin irritation. The available data is considered to support application of the Annex VI harmonized classification of N-hexyl acrylate (Index No. 607-233-00-2) as a Category 2 Skin Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).

 

A weight of evidence evaluation was conducted to determine if classification as an Eye Irritant or substance causing serious eye damage was warranted. N-hexyl acrylate produced evidence of eye irritation in a Klimisch 2 in-vivo study in Rabbits. This result was supported by a positive QSAR prediction of eye irritation. The available data is considered to support application of the Annex VI harmonized classification of N-hexyl acrylate (Index No. 607-233-00-2) as a Category 2 Eye Irritant under the Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).