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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Description of key information

Based on data from the structural analogue acrylic acid, the test substance does not have a potential to cause skin sensitization in animals or humans.

There is no information available on the potential of the test substance to produce respiratory sensitization in animals or humans. Based on its physico-chemical properties (extremely low vapour pressure and solid substance), respiratory sensitization in humans is estimated to be very unlikely.

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
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:
no
Type of study:
Freund's complete adjuvant test
Justification for non-LLNA method:
A reliable in vivo test was available before the implementation of the OECD 429 method.
Specific details on test material used for the study:
- Name of test material (as cited in study report): Acrylic acid
- Analytical purity: 55% (gas chromatigraphy) / >98% after destillation procedure.
- Impurities (concentrations): 45% (gas chromatography) / < 2% after destillation procedure.
Species:
guinea pig
Strain:
other: Himalayan white and Dunkin-Hartley (two strains due to the shortage of animals)
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Himalayan white (Inst. for Biomedical Research, Füllinsdorf, Switzerland) / Dunkin-Hartley (Olac Ltd., Bicester, England)
- Weight at study initiation: 350-450 g
- Housing: in pairs
- Diet (ad libitum): Pellet
- Water (ad libitum): water containing vitamin C
Route:
intradermal
Vehicle:
other: Refer to Details on study design (Traditional tests)
Concentration / amount:
Induction: 0.5 M
Day(s)/duration:
On days 0, 2, 4, 7 and 9
Route:
epicutaneous, open
Vehicle:
other: Refer to Details on study design (Traditional tests)
Concentration / amount:
no concentration given
Day(s)/duration:
day 21 (right flank) and day 35 (left flank)
No. of animals per dose:
8
Details on study design:
RANGE FINDING TESTS:
Skin irritation caused by a single open application was determined for Acrylic acid in FCA pretreated animals (not participating in the sensitization procedure). On the clipped flank of 8 animals 0.025 mL of the test substance was applied with a pipette in progressively diluted (one third) concentrations, each in areas of 2 cm2 marked with a circular stamp. A mixture of 2 parts methyl ethyl ketone and 1 part of peanut oil by volume (Aramek) was used as a solvent. The reactions were read after 24 and 48 h. The maximum nonirritating concentration (m.n.i.c.) was determined, which is the highest concentration not causing a macroscopic reaction in any of the animals.

MAIN STUDY
A. INDUCTION EXPOSURE
After the acid 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.

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 cm2, marked with a circular stamp. The test sites were left uncovered and read at 24 h and 48 h.
Positive control substance(s):
yes
Remarks:
various monoacrylates
Key result
Reading:
1st reading
Group:
test chemical
Dose level:
no data
No. with + reactions:
0
Total no. in group:
8
Remarks on result:
other: Test group (Acrylic acid (destillate, >98%)
Key result
Reading:
1st reading
Group:
test chemical
Dose level:
no data
No. with + reactions:
8
Total no. in group:
8
Remarks on result:
other: Test group (Acrylic acid containing an unidentified impurity of 45%)
Key result
Reading:
1st reading
Group:
negative control
Dose level:
no data
No. with + reactions:
0
Total no. in group:
6
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Group:
positive control
Dose level:
no data
No. with + reactions:
8
Total no. in group:
8
Remarks on result:
positive indication of skin sensitisation
Remarks:
various acrylates have been tested and were positive (result from n-hexyl acrylate)
Interpretation of results:
GHS criteria not met
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1984
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
The study was conducted according to the method described by Klecak (1977) and Van der Walle (1983).
Klecak (1977), Dermatoxicology and Pharmacology. Eds, Marzulli F N, Maibach H I. New York: John Wiley & Sons.
Van der Walle H. B., Waegemaekers T. H., Bensink T. (1983), Contact Dermatitis 9: 10-20.
GLP compliance:
no
Type of study:
other: modified Freund's complete adjuvant test
Justification for non-LLNA method:
At the time of the study there was only the maximization test available and was recommended by regulatory authorities.
Specific details on test material used for the study:
- Name of test material (as cited in study report): Acrylic acid from Merck Schuchardt, impure
- Analytical purity: < 93% (GC)
- Impurities (identity and concentrations): alpha, beta-Diacryloxypropionic acid, 7% (analytically determined), 5-hexenoic acid (identified but not quantified)
Species:
guinea pig
Strain:
Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Strain: Hartley outbred
- Source: Broekman Institute, Netherlands
- Weight at study initiation: 400 g
- Housing: in pairs in steel cages.
- Diet (ad libitum): Pellet food (Hope Farms, Netherlands)
- Water (ad libitum): yes
Route:
intradermal
Vehicle:
water
Remarks:
distilled
Concentration / amount:
1.2% / 0.1 mL
Day(s)/duration:
Day 0, 5, and 9
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
No.:
#1
Route:
epicutaneous, open
Vehicle:
methyl ethyl ketone
Remarks:
2 parts methyl ethyl ketone and one part of peanut oil by volume
Concentration / amount:
0.3 M / 0.025 mL
Day(s)/duration:
Day 21. Readings were performed after 24 and 48 h of administration.
Adequacy of challenge:
highest non-irritant concentration
No.:
#2
Route:
epicutaneous, open
Vehicle:
methyl ethyl ketone
Remarks:
2 parts methyl ethyl ketone and one part of peanut oil by volume
Concentration / amount:
0.3 M / 0.025 mL
Day(s)/duration:
Day 35. Readings were performed after 24 and 48 h of administration.
Adequacy of challenge:
highest non-irritant concentration
No.:
#3
Route:
epicutaneous, open
Vehicle:
methyl ethyl ketone
Remarks:
2 parts methyl ethyl ketone and one part of peanut oil by volume
Concentration / amount:
0.3 M / 0.025 mL
Day(s)/duration:
Day 49. Readings were performed after 24 and 48 h of administration.
Adequacy of challenge:
highest non-irritant concentration
No.:
#1
Route:
epicutaneous, open
Vehicle:
methyl ethyl ketone
Remarks:
2 parts methyl ethyl ketone and one part of peanut oil by volume
Concentration / amount:
1 M / 0.025 mL
Day(s)/duration:
Day 21. Readings were performed after 24 and 48 h of administration
Adequacy of challenge:
highest non-irritant concentration
No.:
#2
Route:
epicutaneous, open
Vehicle:
methyl ethyl ketone
Remarks:
2 parts methyl ethyl ketone and one part of peanut oil by volume
Concentration / amount:
1 M / 0.025 mL
Day(s)/duration:
Day 35. Readings were performed after 24 and 48 h of administration
Adequacy of challenge:
highest non-irritant concentration
No.:
#3
Route:
epicutaneous, open
Vehicle:
methyl ethyl ketone
Remarks:
2 parts methyl ethyl ketone and one part of peanut oil by volume
Concentration / amount:
1 M / 0.025 mL
Day(s)/duration:
Day 49. Readings were performed after 24 and 48 h of administration.
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
8
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: Three
- Exposure period: day 0, 5, and 9
- Test groups: impure acrylic acid, 5-hexenoic acid, a,b-diacryloxypropionic acid
- Control group: no substance was added
- Site: in the shaved nuchal area
- Frequency of applications: not specified
- Duration: 9 days
- Concentrations: 0.17 M for all test substances

B. CHALLENGE EXPOSURE
- No. of exposures: Three
- Day(s) of challenge: Day 21, 35, and 49
- Exposure period: 28 days
- Test groups: impure acrylic acid, 5-hexenoic acid, a,b-diacryloxypropionic acid (DAPA)
- Control group: all test compounds
- Site: shaved contralateral flank
- Concentrations: impure acrylic acid (0.3 M, 1 M), DAPA (0.01 M, 0.03 M), 5-hexenoic acid (1 M, 3 M)
- Evaluation (hr after challenge): 24 h and 48 h
Challenge controls:
Challenge controls received all tested compounds, i.e. impure acrylic acid, DAPA (a,b-diacryloxypropionic acid), and 5-hexenoic acid. Concentrations of the challenge for the control group are not specified.
Reading:
other: Day 21
Group:
test chemical
Dose level:
1 M
No. with + reactions:
8
Total no. in group:
8
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Remarks:
impure acrylic acid
Reading:
other: Day 35
Group:
test chemical
Dose level:
1 M
No. with + reactions:
8
Total no. in group:
8
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Remarks:
impure acrylic acid
Reading:
other: Day 21
Group:
test chemical
Dose level:
0.3 M
No. with + reactions:
1
Total no. in group:
8
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Remarks:
impure acrylic acid
Reading:
other: Day 49
Group:
test chemical
Dose level:
0.3 M
No. with + reactions:
7
Total no. in group:
8
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Remarks:
impure acrylic acid
Reading:
other: Day 21
Group:
negative control
Dose level:
no data
No. with + reactions:
0
Total no. in group:
8
Remarks on result:
no indication of skin sensitisation
Group:
positive control
Dose level:
no data
Remarks on result:
not measured/tested

Table 1: Sensitizing potential in the modified Freund's Adjuvant Test

















































Test substance



Induction



Challenge concentration*)



Number of sensitized animals/number of tested animals



Day 21



Day 35



Day 49



Acrylic acid, from Merck Schuchardt



3•0.17 M


(= 1.2%)



1 M


0.3 M



8/8


1/8



8/8


N.T.



N.T.


7/8



DAPA



1•0.17 M**)


(= 3.6%)



0.03 M


0.01 M



8/8


7/8



N.T.


7/8



N.T.


7/8



5-hexenoic acid



3•0.17 M


(= 1.9%)



3 M


1 M



0/8


0/8



0/8


0/8



0/8


0/8



controls



3•FCA dist. water



All the above compounds



0/8



0/8



0/8



N.T. = not tested


*) = In Aramek, 2 parts methyl ethyl ketone, one part peanut oil by volume


**) = Different induction procedure

Interpretation of results:
study cannot be used for classification
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
Qualifier:
no guideline followed
Principles of method if other than guideline:
- Principle of test: Modified Maguire Method (Maguire H. C., The Bioassay of Contact Allergens in the Guinea Pig, J. Soc. Cosmet. Chem., 24, 151, 1973).
- Short description of test conditions: The Maguire method derives from the "split adjuvant" technique, in which chemical allergen and Freund' s adjuvant are administered separately to the skin rather than as an emulsion. A typical test procedure consisted of topical application of a 0.1 mL aliquot of the test material to the clipped and depilated backs of 10 guinea pigs four times in 10 days. At the time of the third application, 0.2 mL of Freund's adjuvant was injected intradermally at one point adjacent to the insult site. After a 2-week rest period, the animals were challenged on the clipped flanks with the test material on one flank and a solvent (if used) on the other flank.
- Parameters analysed / observed: The challenge site was evaluated for erythema and edema at 24 and 48 hours. A moderate erythema and/or edema in two or more animals was considered sufficient to classify the test material as a potential human skin sensitizer.
GLP compliance:
no
Type of study:
split adjuvant test
Justification for non-LLNA method:
A reliable in vivo test was available before the implementation of the OECD 429 method.
Specific details on test material used for the study:
- Name of test material (as cited in study report): Acrylic acid
- Analytical purity: no data
Species:
guinea pig
Strain:
Hartley
Sex:
male
Route:
epicutaneous, occlusive
Vehicle:
no data
Concentration / amount:
0.1 mL aliquot of the test substance
Route:
epicutaneous, occlusive
Vehicle:
no data
Concentration / amount:
not specified
No. of animals per dose:
10
Details on study design:
RANGE FINDING TESTS:
Prior to conducting the sensitization test, the test material was applied as received to the clipped flanks of animals to determine if primary irritation would occur. If significant irritation was observed, dilutions of the test material were made in a suitable solvent. The highest concentration which did not cause primary irritation was used for the sensitization test.

MAIN STUDY
A. INDUCTION EXPOSURE
- Control group: For induction, 10 guinea pigs were routinely subjected to the same dosing regimen with the diglycidyl ether of 2,2-di-(p,p'-hydroxyphenyl)propane (DER* 331 Epoxy Resin -- Dow Chemical U .S .A .), a known sensitizer to serve as a positive control .

B. CHALLENGE EXPOSURE
- Control group: Challenge was performed two weeks after the last injection of the induction series.
Positive control substance(s):
yes
Remarks:
2,2-Di-(p,p'-hydroxyphenyl)propane didlycidyl ether (DER* 331 Epoxy Resin -- Dow Chemical U .S .A .)
Positive control results:
The positive reference substance ( DER* 331 Epoxy Resin) induced moderate skin sensitization.
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.1 mL
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
no data
No. with + reactions:
7
Total no. in group:
10
Group:
negative control
Remarks on result:
not measured/tested

Table 1: Results of the test group


 
















Substance



animals tested



animals sensitized



Acrylic acid (0.1 mL aliquot)



10



0



 


Sensitization with the test substance was not observed in this test.

Interpretation of results:
GHS criteria not met
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

No experimental data on the test substance is available.

Sodium acrylate is the sodium salt of acrylic acid, only the proton of the hydroxy group has been replaced by a sodium ion in NaA. Both are equally charged ions.pH dependent sodium acrylate dissociates into acrylic acid and sodium hydroxid in aqueous media.

According to Henderson-Hasselbalch: pH = pKs + lg (c(NaAcrylate) / c(Acrylic acid))

With the pKa-value of acylic acid = 4.25.

The ratio c(NaAcrylate) / c(Acrylic acid) was caluclated according to the Henderson-Hasselbalch equation: c(NaAcrylate) / c(Acrylic acid)) = 10 pH - pKs

pH 1 : c(NaAcrylate) / c(Acrylic acid)) = 10 1 – 4,25 = 0,00056; ~ 99,94 % as acrylic acid

pH 3 : c(NaAcrylate) / c(Acrylic acid)) = 10 3 – 4,25 = 0,056; t ~ 94,7 % as acrylic acid

pH 5 : c(NaAcrylate) / c(Acrylic acid) = 10 5 – 4,25 = 5,62; ~ 15,1 % as acrylic acid

pH 7 : c(NaAcrylate) / c(Acrylic acid) = 10 7 – 4,25 = 562,3; ~ 0,2 % as acrylic acid

Especially after oral uptake in the acidic environment in the stomach sodium acrylate is nearly completely dissociated to acrylic acid. Therefore, it is appropriate to use the human health hazard data of acrylic acid for the assessment of sodium acrylate. In respect to the hazard data on ecotoxicity, using the acrylic acid data assuming a complete dissociation reflects the worst case.

Therefore, the evaluation of the endpoint sensitization is based on a weight of evidence approach using the toxicological data of the structural analogue acrylic acid (CAS 79-10-7) (for WoE information, see chapter 13.2).

Acrylic acid was tested in guinea pigs using a modified Split Adjuvant Test procedure. The highest concentration which did not cause primary irritation was used but no data were given on the test concentrations. Ten animals per test received a 0.1 ml aliquot of acrylic acid to the backs four times in 10 days. At the time of the third application, 0.2 ml Freund's adjuvant was injected at one point adjacent to the insult site. After a 2-week rest period, the guinea pigs were challenged with the test material on one flank and a solvent (if used) on the other flank. The challenge site was evaluated for erythema and oedema at 24 and 48 hours. Acrylic acid was negative (0/10) (Rao et al., 1981).

 

Van der Walle et al. (1982) reported a sample of commercial grade acrylic acid to be sensitizing in a Freund’s Complete Adjuvant test. 8/8 guinea pigs were sensitized. However, analysis by gas chromatography revealed an impurity of 45 % in this sample. The sample of acrylic acid was distilled in vacuo and the sensitized animals were tested with the distillate (containing >98% acrylic acid) and with the residue. None of the animals reacted to the distillate but all the animals reacted to the residue. The identity of the allergen in this residue was under investigation at the time of publication of this paper.

 

In a modified Freund's Complete Adjuvant test 8 guinea pigs/group received 3 intradermal injections during the induction phase on days 0, 5 and 9 (the test substance was mixed with FCA in a volume of 0.1 ml). Non-irritant test concentrations were used for challenge at day 21. The test concentrations for intradermal injections were 3 x 0,17 M (1.2%) in water and for challenge 1 and 0.3 M in Aramek, a mixture of 2 parts methyl ethyl ketone and 1 part of peanut oil. Distilled acrylic acid was negative but commercial acrylic acid proved to be a strong skin sensitizer. The skin reactions were due to the presence of varying quantities (up to 7%) of a,ß-diacryloxypropionic acid (DAPA). Positive skin reactions were still present after a third challenge on day 49 (Waegemakers and Van der Walle, 1984).

 

Based on the presented data, acrylic acid does not have a skin sensitizing potential in animal studies. Positive test results obtained with commercial grade samples of the compound were caused by the presence of the impurity DAPA.

 

Based on the structural similiarties to acrylic acid it is anticipated that the test substance will not cause skin sensitisation in animals and humans.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result, the substance is not considered to be classified for sensitization under Regulation (EC) No. 1272/2008, as amended for the fourteenth time in Regulation (EC) No. 2020/217.