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Diss Factsheets

Administrative data

Description of key information

Skin irritation (QSAR): not irritating 
Skin irritation (OECD 404): not irritating; CAS# 57-10-3, C16 (Kästner, 1988)
Skin irritation (Federal Guidelines): not irritating; CAS# 57-11-4, C18 (USFHSA, 1974)
Skin irritation (human, closed epicutaneous test): not irritating; CAS# 57-10-3, C16 (Matthies, 1988)
Skin irritation (human, repeated occlusive patch test, 1M): not irritating CAS# 57-10-3, C16; CAS# 57-11-4, C18 (Stillman et al., 1975)
Eye irritation (QSAR): not irritating 
Eye irritation (OECD 404): not irritating; CAS# 57-10-3, C16 (Kästner, 1988)
Eye irritation (Federal Guidelines): not irritating; CAS# 57-11-4, C18 (USFHSA, 1974)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin irritation / corrosion, other
Remarks:
other: Qualitative SAR based on structural alerts and PC data
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Qualitative SAR based on structural alerts and PC data
Justification for type of information:
QSAR prediction
Reason / purpose for cross-reference:
reference to same study
Principles of method if other than guideline:
Determination with the OECD QSAR Toolbox v2.2 whether inclusion rules (based on structural alerts) and exclusion rules (based on PC parameters) are fulfilled for skin irritation/corrosion for docosanoic acid. The results were compared with erucic acid.
GLP compliance:
no
Species:
other: not applicable
Strain:
other: not applicable
Type of coverage:
other: not applicable
Preparation of test site:
other: not applicable
Vehicle:
other: not applicable
Controls:
other: not applicable
Duration of treatment / exposure:
not applicable
Observation period:
not applicable
Number of animals:
not applicable
Irritation / corrosion parameter:
other: inclusion rules (based on structural alerts)
Run / experiment:
Docosanoic acid
Remarks on result:
other: no alerts, thus neither irritating nor corrosive
Irritation / corrosion parameter:
other: exclusion rules (based on PC parameters)
Run / experiment:
Docosanoic acid
Remarks on result:
other: neither irritating nor corrosive

Table 1: Physico-chemical parameters for docosanoic acid and erucic acid, on which the skin irritation/corrosion potential is predicted: 

Chemical name, short notation

Docosanoic acid, C22

Erucic acid, C22’

Molecular weight, g/mol

340.6

338.6

log Kow

9.91 (KOWWIN v1.68)

9.69 (KOWWIN v1.68)

Melting point, °C

81 (EPISUITE exp. database)

33.5 (EPISUITE exp. database)

Vapour pressure Pa

6.5E-5 (MPBPWIN v1.43 at 25 °C)

1.5E-4 (MPBPWIN v1.43 at 25 °C)

Water solubility, mg/L

0.016 mg/L (EPISUITE exp. database at room temperature)

insoluble (Merck Index)

 

Table 2: Application of exclusion rules for docosanoic acid (C22) and erucic acid (C22')

Rule

Class of substances

Positive for C22, C22’:

If positive, than NOT:

log Kow > 9

all

both substances

R34, R35

WS < 0.1 mg/L

C, H, O only

both substances

R34, R35

MP > 55 °C

C, H, O only

C22 only

R34, R35, R38

VP < 1E-4 Pa

C, H, O only

C22 only

R38

MW > 350

C, H, O only

neither substance

R34, R35

LS < 0.01 g/kg

all

neither substance

R34, R35

ST > 62 mN/m

C, H, O only

rule discarded due to

low water solubility

R34, R35

WS: water solubility

MP: melting point

VP: vapour pressure

MW: molecular weight

LS: lipid solubility

ST: surface tension

Interpretation of results:
other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008
Remarks:
Criteria used for interpretation of results: Qualitative SAR based on structural alerts and PC data
Endpoint:
skin irritation: in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Study period:
29 Jan - 04 Feb 1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP - Guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
application under occlusion; 4 animals used;
GLP compliance:
yes
Species:
rabbit
Strain:
other: Kleinrusse, Chbb: HM
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Fa. Thomae, Biberach/D.
- Weight at study initiation: mean: 2452.5 g
- Housing: individually housed in rabbit batteries, Fa. Heinkel, 7343, Kuchen, D
- Diet: Zucht- /Haltungsdiät 20 ZH 5, Fa. Nohrlin GmbH, 4902 Bad Salzuflen; ad libitum
- Water: ad libitum tap water
- Acclimation period: at least 1 week


ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca. 20 - 21
- Humidity (%): ca. 45 - 50
- Photoperiod (hrs dark / hrs light): 12 / 12

Type of coverage:
occlusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g
Duration of treatment / exposure:
4 hours
Observation period:
3 days; since no scores could be observed within 3 days the experiment was cancelled due to animal welfare reasons; therefore the short observation period of 3 days does not represent a deviation to the OECD Guideline 404
Number of animals:
4
Details on study design:
TEST SITE
- Area of exposure: ~2.5 x 2.5 cm
- Type of wrap if used: plastic foil with adhesive plasters and an acrylastic band aid

SCORING SYSTEM: Skin irritation/corrosion was evaluated according to Draize.
Irritation parameter:
erythema score
Basis:
animal: #1, #2, #3, #4
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: reversibility not applicable
Remarks on result:
no indication of irritation
Irritation parameter:
edema score
Basis:
animal: #1, #2, #3, #4
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: reversibility not applicable
Remarks on result:
no indication of irritation
Irritant / corrosive response data:
No skin reactions were observed.
Interpretation of results:
other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
CLP: not classified
Endpoint:
skin irritation: in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test procedure according to national standards (DIN, etc.)
Qualifier:
according to guideline
Guideline:
other: Patch test / Revised (1964) Federal Hazardous Substance Act
Deviations:
not specified
GLP compliance:
no
Species:
rabbit
Strain:
New Zealand White
Type of coverage:
occlusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
0.5 mL
Duration of treatment / exposure:
24 hours
Observation period:
72 hours
Reading time points: 24 h and 72 h
Number of animals:
6
Details on study design:
Fur was removed from the back of each of six rabbits by clipping the saddle of the trunk area. One area of skin was abraded by making minor incisions with a hypodermic needle. 0.5 mL of test material was applied to 1 inch gauze patches. The patches were placed on both intact skin and abraded skin of each rabbit and secured with adhesive tape, rubber dental damming secured with staples, and gauze wound loosely around the trunk. The animals were then immobilized for 24 hours in wooden stocks. After 24 hours, the patches were removed and the skin cleaned by gently sponging with a moistened towel. The skin was examined immediately after removal of the patches (24 hr reading) and again at 72 hrs. At each examination the skin was scored for presence and severity of erythema/eschar formation and edema formation.
Irritation parameter:
erythema score
Basis:
mean
Remarks:
out of all 6 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: not applicabe
Remarks on result:
other: intact sites
Irritation parameter:
edema score
Basis:
mean
Remarks:
out of all 6 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: not applicable
Remarks on result:
other: intact sites
Irritant / corrosive response data:
No signs of skin irritation were observed on intact or abraded sites at either reading time point.

Material (0.5 mL) was applied via a one-inch-square surgical gauze patch to intact and abraded-skin sites. Patches were held in place for 24 hours. Reactions were scored immediately after patch removal and two days later (72 hours).

Scores for Skin Irritation

Rabbit No.

24 hrs

72 hrs

43

Intact

     Erythema-Eschar

     Edema

Abraded

     Erythema-Eschar

     Edema

0    

0

0

0

0

0

0

0

44

Intact

     Erythema-Eschar

     Edema

Abraded

     Erythema-Eschar

     Edema

0    

0

0

0

0

0

0

0

45

Intact

     Erythema-Eschar

     Edema

Abraded

     Erythema-Eschar

     Edema

0    

0

0

0

0

0

0

0

46

Intact

     Erythema-Eschar

     Edema

Abraded

     Erythema-Eschar

     Edema

0    

0

0

0

0

0

0

0

47

Intact

     Erythema-Eschar

     Edema

Abraded

     Erythema-Eschar

     Edema

0    

0

0

0

0

0

0

0

48

Intact

     Erythema-Eschar

     Edema

Abraded

     Erythema-Eschar

     Edema

0    

0

0

0

0

0

0

0
Interpretation of results:
other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
CLP: not classified
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Referenceopen allclose all

Endpoint:
eye irritation, other
Remarks:
other: Qualitative SAR based on structural alerts and PC data
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Qualitative SAR based on structural alerts and PC data
Justification for type of information:
QSAR prediction
Reason / purpose for cross-reference:
reference to same study
Principles of method if other than guideline:
Determination with the OECD QSAR Toolbox v2.2 whether inclusion rules (based on structural alerts) and exclusion rules (based on PC parameters) are fulfilled for eye irritation/corrosion for docosanoic acid. The results were compared with erucic acid.
GLP compliance:
no
Species:
other: not applicable
Strain:
other: not applicable
Vehicle:
other: not applicable
Controls:
other: not applicable
Duration of treatment / exposure:
not applicable
Observation period (in vivo):
not applicable
Number of animals or in vitro replicates:
not applicable
Irritation parameter:
other: inclusion rules (based on structural alerts)
Basis:
other: docosanoic acid
Remarks on result:
other: no alerts, thus neiter irritating nor corrosive
Irritation parameter:
other: exclusion rules (based on PC parameters)
Basis:
other: docosanoic acid
Remarks on result:
other: not R34, R35, R36 and R41

Table 1: Physico-chemical parameters for docosanoic acid and erucic acid, on which the skin irritation/corrosion potential is predicted: 

Chemical name, short notation

Docosanoic acid, C22

Erucic acid, C22’

Molecular weight, g/mol

340.6

338.6

log Kow

9.91 (KOWWIN v1.68)

9.69 (KOWWIN v1.68)

Melting point, °C

81 (EPISUITE exp. database)

33.5 (EPISUITE exp. database)

Vapour pressure Pa

6.5E-5 (MPBPWIN v1.43 at 25 °C)

1.5E-4 (MPBPWIN v1.43 at 25 °C)

Water solubility, mg/L

0.016 mg/L (EPISUITE exp. database at room temperature)

insoluble (Merck Index)

 

Table 2: Application of exclusion rules for docosanoic acid (C22) and erucic acid (C22')

Rule

Class of substances

Positive for C22, C22’:

If positive, than NOT:

log Kow > 9

all

both substances

R34, R35, R36, R41

WS < 0.1 mg/L

all

both substances

R34, R35, R36, R41

MP > 55 °C

C, H, O only

C22 only

R34, R35

MW > 380

C, H, O only

neither substance

R34, R35, R36, R41

LS < 0.01 g/kg

all

neither substance

R34, R35, R36, R41

WS: water solubility

MP: melting point

MW: molecular weight

LS: lipid solubility

Interpretation of results:
other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008
Remarks:
Criteria used for interpretation of results: Qualitative SAR based on structural alerts and PC data
Endpoint:
eye irritation: in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Study period:
26 Feb - 04 Mar 1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP - Guideline study tested with the source substance CAS 57-10-3. In accordance to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 405 (Acute Eye Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes
Species:
rabbit
Strain:
other: Kleinrussen Chbb
Details on test animals or tissues and environmental conditions:
TEST ANIMALS
- Source: HM / Fa. Thomae, Biberach, Germany
- Weight at study initiation: ca. 2640 g
- Housing: individually (Fa. Heinkel, Kuchen, Germany)
- Diet: ad libitum Altromin diet 2023, Altromin GmbH, Lage, Germany
- Water: ad libitumcommunity tap water; ad libitum
- Acclimation period: at least 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca. 20 - 21
- Humidity (%): 45 - 55
- Photoperiod (hrs dark / hrs light): 12 / 12
Vehicle:
unchanged (no vehicle)
Controls:
other: the untreated left eyes served as control
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 g
Duration of treatment / exposure:
single application without washing
Observation period (in vivo):
3 days (since only minor scores were observed that fully returned to normal within 3 days the experiment was cancelled due to animal welfare reasons; therefore the reduced observation period does not represent a deviation to the OECD Guideline)
Reading time points: 1 h, 6 h, 24 h, 48 h, 72 h after administration
Number of animals or in vitro replicates:
4
Details on study design:
TOOL USED TO ASSESS SCORE: fluorescein
Ca. 24 hours prior to administration the eyes of the rabbits were checked with 0.1 mL 0.5% fluorescein sodium solution to detect eye lesions. If there are no stainings after rinse off, the cornea is considered to be intact. 24 hours after application of the test item and macroscopical determination of mucosal irritation the treatment with fluorescein sodium solution was repeated.
Irritation parameter:
cornea opacity score
Basis:
mean
Remarks:
out of all 4 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: not applicable
Irritation parameter:
iris score
Basis:
mean
Remarks:
out of all 4 animals
Time point:
24/48/72 h
Score:
0
Max. score:
2
Reversibility:
other: not applicable
Irritation parameter:
conjunctivae score
Remarks:
redness
Basis:
mean
Remarks:
out of all 4 animals
Time point:
24/48/72 h
Score:
0.3
Max. score:
3
Reversibility:
fully reversible within: 48 hours
Irritation parameter:
chemosis score
Basis:
mean
Remarks:
out of all 4 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: not applicable
Irritation parameter:
other: exudation
Basis:
mean
Remarks:
out of all 4 animals
Time point:
other: mean over 24, 48 and 72 h
Score:
0
Max. score:
3
Reversibility:
other: not applicable

Tab.1: Conjunctival reactions after application of 0.1 g Edenor C16 - 92/94 (undiluted, permanent, 4 male rabbits)

Time point after application

Redness

Chemosis

Exudation

Individual data

Average

Individual data

Average

Individual data

Average

60 min

1 / 1 / 1 / 1

1.00

0 / 1 / 1 /1

0.75

0 / 0 / 0 / 1

0.25

6 h

1 / 2/ 1 / 1

1.25

0 / 0 / 0 / 0

0

2 / 0 / 0 / 1

0.75

24 h

1 / 1 / 1 / 1

1.00

0 / 0 / 0 / 0

0

0 / 0 / 0 / 0

0

48 h

0 / 0 / 0 / 0

0

0 / 0 / 0 / 0

0

0 / 0 / 0 / 0

0

72 h

0 / 0 / 0 / 0

0

0 / 0 / 0 / 0

0

0 / 0 / 0 / 0

0

Animal No. (from left to right) 790, 796, 798, 799

Reactions on the cornea and iris were not observed. The conjunctival reactions were slight and disappeared totally within 48 hours. Palmitic acid is not irritating to eyes / mucosa under the test conditions.

Interpretation of results:
other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
CLP: not classified
Endpoint:
eye irritation: in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Studies conducted pre-GLP standards
Qualifier:
according to guideline
Guideline:
other: Regulations for the Enforcement of the Federal Hazardous Substances Act. F.R. Sept. 17, 1964
GLP compliance:
no
Species:
rabbit
Strain:
other: Albino
Vehicle:
not specified
Controls:
other: the untreated left eye served as control
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL
Observation period (in vivo):
Reading time points: 24, 48 and 72 hours
Number of animals or in vitro replicates:
6
Irritation parameter:
iris score
Basis:
mean
Remarks:
out of all 6 animals
Time point:
24/48/72 h
Score:
0
Max. score:
2
Reversibility:
other: not applicable
Irritation parameter:
chemosis score
Basis:
mean
Remarks:
out of all 6 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: not applicable
Irritation parameter:
conjunctivae score
Basis:
mean
Remarks:
out of all 6 animals
Time point:
24/48/72 h
Score:
0
Max. score:
3
Reversibility:
other: not applicable
Irritation parameter:
cornea opacity score
Basis:
mean
Remarks:
out of all 6 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: not applicable
Irritant / corrosive response data:
No Lesions were observed after application of 0.1 mL test substance in rabbits eyes.

Scores for Ocular Lesions

Rabbit No.

24 hrs.

48 hrs.

72 hrs.

13

Cornea opacity, degree

Cornea opacity, area

Iris

Conjunctiva

    Redness

    Chemosis

    Discharge

0    

0    

0

0

0

0

0  

0  

0

0

0

0

0

0

0

0

0

0

14

Cornea opacity, degree

Cornea opacity, area

Iris

Conjunctiva

    Redness

    Chemosis

    Discharge

0    

0    

0

0

0

0

0  

0  

0

0

0

0

0

0

0

0

0

0

15

Cornea opacity, degree

Cornea opacity, area

Iris

Conjunctiva

    Redness

    Chemosis

    Discharge

0    

0    

0

0

0

0

0  

0  

0

0

0

0

0

0

0

0

0

0

16

Cornea opacity, degree

Cornea opacity, area

Iris

Conjunctiva

    Redness

    Chemosis

    Discharge

0    

0    

0

0

0

0

0  

0  

0

0

0

0

0

0

0

0

0

0

17

Cornea opacity, degree

Cornea opacity, area

Iris

Conjunctiva

    Redness

    Chemosis

    Discharge

0    

0    

0

0

0

0

0  

0  

0

0

0

0

0

0

0

0

0

0

18

Cornea opacity, degree

Cornea opacity, area

Iris

Conjunctiva

    Redness

    Chemosis

    Discharge

0    

0    

0

0

0

0

0  

0  

0

0

0

0

0

0

0

0

0

0
Interpretation of results:
other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
CLP: not classified
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Skin

No data on skin irritation/corrosion is available for docosanoic acid. Therefore skin irritation effects are predicted from adequate and reliable data for source substances by read-across to the target substance within the group applying the group concept in accordance with Annex XI, Item 1.5, of Regulation (EC) No 1907/2006. In particular, the source substances structurally closest to the target substance are chosen for read-across, with due regard to the requirements of adequacy and reliability of the available data. Thus, studies with C16 fatty acid (palmitic acid) and C18 fatty acid (stearic acid) are used for hazard assessment.

Skin irritation by palmitic acid (CAS# 57-10-3) was evaluated in a study performed under GLP according to OECD Guideline 404 with the exception, that the test was performed under occlusive condition (Kästner, 1988). Four Himalayan rabbits received an application of 0.5 g palmitic acid to the shaved skin under occlusion for 4 hours. The readings 24, 48, and 72 hours after application did not reveal any signs of irritation, thus resulting in mean scores of 0 for erythema and edema, respectively. As a consequence, the test was terminated after the 72 h reading. Based on the results, palmitic acid can be regarded as not irritating to skin.

In a study with human subjects, palmitic acid and 19 other substances were investigated with a closed epicutaneous test. 10 µL of palmitic acid at a concentration of 50% were applied to the back of the volunteers for 24 hours using a Large Finn Chamber (Matthies, 1988). The reactions were scored for edema, erythema, scaling and fissures 1, 6, 24, 48, 72 and 144 hours after application. As result, for all readings the score 0 was found. In another study with human subjects, 12.8% and 25.6% (w/v) palmitic acid was applied daily under occlusive patch tests to human skin until detectable erythema appeared (Stillman et al., 1975). Only one single subject showed erythema after six days of repeated application of 12.8% palmitic acid.

 

Skin irritation by stearic acid (CAS# 57-11-4) was evaluated in a study performed in accordance with US Federal Guidelines (USFHSA, 1974). 0.5 mL of stearic acid was applied to the abraded skin of 6 New Zealand White rabbits under occlusion for 24 hours.at 24 and 72 hours after application revealed no signs of irritation. Although a longer application under occlusion than suggested according to actual guidelines was applied, the resulting scores were 0 for erythema and edema, respectively. Based on this, stearic acid can be regarded as not irritating to skin.

In a study with human subjects, daily application of 28.4% stearic acid (w/v) under occlusive conditions did not cause irritation in any of the 10 subjects until the termination of the study on day 10 (Stillman et al., 1975).

 

Based on the available data, palmitic acid and stearic acid have no skin irritation potential.

Due to the structural and functional similarities of members within the category including docosanoic acid, palmitic acid and stearic acid, the same result could be expected for docosanoic acid. To support this negative result, a qualitative SAR method has been applied for docosanoic acid. By means of the OECD QSAR toolbox (v2.2) it can be determined whether inclusion rules (examination for the presence of structural alerts) and exclusion rules (on the basis of physico-chemical properties) are fulfilled for skin irritation/corrosion. No alerts were detected for docosanoic acid and a skin irritation/corrosion classification (R34, R35, R38) can be excluded based on the basis of log Kow, water solubility, melting point and vapour pressure based rules.

In conclusion, docosanoic acid is not regarded as irritating to skin based on a weight of evidence approach.

Eye

No data on eye irritation is available for docosanoic acid.Therefore eye irritation effects are predicted from adequate and reliable data for source substances by read-across to the target substance within the group applying the group concept in accordance with Annex XI, Item 1.5, of Regulation (EC) No 1907/2006. In particular, the source substances structurally closest to the target substance are chosen for read-across, with due regard to the requirements of adequacy and reliability of the available data. Thus, studies with C16 fatty acid (palmitic acid) and C18 fatty acid (stearic acid) are used for hazard assessment.

Eye irritation by palmitic acid (CAS# 57-10-3) was analysed in a study performed in accordance with GLP and according to OECD Guideline 405 (Kästner, 1988). 0.1 g of palmitic was instilled into the right eye each of four Himalayan rabbits while the untreated left eyes served as control. The reactions were examined 1, 6, 24, 48, and 72 hour after administration and resulted in mean scores of 0, 0, 0.3, 0 and 0 for corneal opacity, iris, conjunctival redness and chemosis, and exudation, respectively. Since all signs were subsided on day three after instillation, the study was terminated on that day due to animal welfare reasons. Based on the findings, palmitic acid can be regarded as not irritating to eyes.

Palmitic acid was also found to be not irritating to eyes in a study performed according to national guidelines since no signs of irritation were noted in any of six treated rabbits (Briggs et al., 1976).

Eye irritation by stearic acid (CAS# 57-11-4) was examined in a non-GLP study according to US Federal Guidelines (USFHSA, 1974). 0.1 g stearic acid was applied into the eyes of six albino rabbits. The untreated left eye of each animal served as control. The eyes were examined at 24, 48 and 72 h and scored for corneal opacity, iris lesions, conjunctival redness, chemosis and discharge. No lesions were observed in any of the animals, thus the overall score for all irriation parameters was 0.

Thus, palmitic acid and stearic acid are not irritating to the eyes based on the available animal studies.

For docosanoic acid a qualitative SAR based on structural alerts and PC data was performed to make a prediction for its eye irritation potential. No structural alerts for eye irritation have been determined for docosanoic acid and classification as R34, R35, R36 and R41 could be excluded due to the log Kow, water solubility and melting point based rules.

 

In conclusion by means of read-across based on a category approach and taking into account QSAR predictions, docosanoic acid is not considered as irritating to eyes.

 

References:

Briggs, G.B. et al. (1976). Safety studies on a series of fatty acids. Am Ind Hyg Assoc J. 37(4):251-253. International Bio-Research, Miamiville, Ohio, USA.


Justification for classification or non-classification

By means of read-across based on a category approach, the available data on skin and eye irritation does not meet the criteria for classification according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.