Reaction products of 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C11-17 and C17 unsatd. alkyl) derivs. and sodium hydroxide and 2-propenoic acid

Endpoint summary

Description of key information

Skin irritation: 
not irritating: OECD TG 439; RL1, GLP: 102.1% relative tissue viability 102.1%
Eye irritation
irreversible effects on the eyes (Category 1): OECD TG 438 incl. histopathological assessment; RL1, GLP: Maximal mean score for corneal opacity : 2.3 (ICE Class III), Mean score of Fluorescein Retention : 0.7 (ICE Class II), Maximal Corneal swelling : 20.09% (ICE Class III)  

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-07-28 to 2015-10-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

(Original Guideline adopted July 28, 2015)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

accordign to guideline

Vehicle:

unchanged (no vehicle)

Details on test system:

EpiSkin™ kits are purchased from SkinEthic Laboratories (69007 Lyon, France). The EpiSkin™ tissue consists of normal, human-derived epidermal keratinocytes which have been cultured to form a multilayered, highly differentiated model of the human epidermis. It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo.
The EpiSkin™ tissues (surface 0.38 cm²) are cultured on specially prepared cell culture inserts. EpiSkin™ tissues were shipped at ambient temperature on medium-supplemented agarose gels in a 12-well plate and reached Envigo CRS GmbH on 20 October 2015. On the same day of experiment EpiSkin™ tissues were transferred to 12-well plates with maintenance medium and the pre-incubation phase of the EpiSkin™ tissues started.

TREATMENT:
Three tissues of the human skin model EpiSkin™ were treated each with 10 µL of the test item, the negative control (deionised water) or the positive control (5% Sodium lauryl sulfate) for 15 minutes.
After the end of the treatment interval the inserts were removed immediately from the 12-well plate. Using a wash bottle the tissues were gently rinsed with PBS to remove any residual test material. Excess PBS was removed by gently shaking the inserts and blotting the bottom with blotting paper. The inserts were placed in the plates with 2 mL maintenance medium. The tissues were incubated for nearly 43 hours at 37 ± 1.5 °C, 5 ± 0.5% CO2 .

MTT ASSAY:
The MTT concentrate was prepared freshly and diluted with the MTT diluent. A 12-well plate was filled with 2 mL assay medium containing 0.3 mg/mL MTT per well.
After the treatment procedure was completed for all tissues the cell culture inserts were transferred from the holding plates to the MTT-plates. After a 3 hour incubation period (37 ± 1.5 °C, 5 ± 0.5% CO2) MTT solution was aspirated from the wells and the wells were rinsed three times with PBS. Tissue samples were cut out of the inserts with a biopsy punch and transferred into plastic vials. The tissue samples were immersed into extractant solution by gently pipetting 0.5 mL extractant solution (isopropanol containing 0.04 N HCl) into each vial. The tissue samples were completely covered by isopropanol. The vials were sealed to inhibit isopropanol evaporation. The formazan salt was extracted for about 68 hours without shaking in the refrigerator.
Per each tissue sample 2 × 200 µL aliquots of the formazan blue solution were transferred into a 96-well flat bottom microtiter plate. OD was read in a microplate reader (Versamax® Molecular Devices, 85737 Ismaning, Germany, version 4.7.1) with 570 ± 1 nm filter. Mean values were calculated from the 2 wells per tissue sample.

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 µL (26.3 µL/cm²)
- Concentration (if solution): 40% a.i.

Duration of treatment / exposure:

15 minutes

Duration of post-treatment incubation (if applicable):

43 h

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Value:

102.1

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

The mean relative absorbance value of the test item, corresponding to the cell viability, did not decrease (102.1%; threshold for irritancy ≤ 50%), consequently the test item was not irritant to skin.

Evaluation of Results:

The mean OD of the three negative control tissues was calculated. This value corresponds to 100% tissue viability in the current test.

For the test item and the positive control the mean relative viability ± rel. standard deviation of the three individual tissues are calculated and used for classification according to the following prediction model:

For the current test, an irritation potential of a test item according to EU classification H315 (according to regulation (EC) 1272/2008), and GHS category 2 according to UN GHS (published 2003, last (3rd) revision 2009) is recommended if the mean relative tissue viability of three individual tissues is reduced ≤ 50% of the negative control.

Results after treatment with test item and controls

Dose Group	Treatment Interval	Absorbance 570 nm Tissue 1	Absorbance 570 nm Tissue 2	Absorbance 570 nm Tissue 3	Mean Absorbance of 3 Tissues	Relative Absorbance [%] Tissue 1,2,3	Relative Standard Deviation [%]	Rel. Absorbance [% negative control]
Negative control	15 min	0.991	0.915	0.870	0.925	107.1	6.6	100.0
						98.9
						94.1
Positive control	15 min	0.113	0.134	0.139	0.129	12.2	10.6	13.9
						14.5
						15.0
Test Item	15 min	0.917	0.973	0.943	0.944	99.1	3.0	102.1
						105.1
						102.0

The optical pre-experiment (colour interference pre-experiment) to investigate the test item’s colour change potential in water did not led to a change in colour. Optical evaluation of the MTT-reducing capacity of the test item after 3 hours incubation with MTT-reagent did not show blue colour.

Interpretation of results:

GHS criteria not met

Conclusions:

In this in vitro skin irritation test Amphopropionates C12-18 (40% a.i.) was not irritating.

Executive summary:

In an in vitro dermal irritation study according to OECD guideline 439, adopted July 28, 2015, Amphopropionates C12-18 (40% a.i.) was applied in triplicate (10 µL) to human skin model EpiSkin™ tissues for 15 min. Deionised water was used as negative control, 5% SLS as positive control. After exposure the skin tissues were thoroughly rinsed to remove the test substance and transferred to fresh medium.

After a 43-hour post-treatment incubation the cell viability measured by dehydrogenase conversion of MTT into a blue formazan salt was assessed as predictor for skin irritancy potential. 

After treatment with the negative control the absorbance values were well within the required acceptability criterion of mean OD ≥ 0.6 till ≤ 1.5 for the 15 minutes treatment interval thus showing the quality of the tissues. Treatment with the positive control induced a sufficient decrease in the relative absorbance as compared to the negative control for the 15 minutes treatment interval thus ensuring the validity of the test system.

The relative mean tissue viability obtained after 15 minutes treatment with the test substance compared to the negative control tissues was 102.1%. Since the mean relative tissue viability was above 50%, the test substance is considered to be non-irritant.

The positive control had a mean cell viability of 13.9% after 15 minutes exposure.

In this in vitro skin irritation test Amphopropionates C12-18 (40% a.i.) was not irritating.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye Test Method for Identifying Ocular Corrosives and Severe Irritants)

Version / remarks:

July 26th 2013

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

chicken

Details on test animals or tissues and environmental conditions:

TEST SYSTEM
- Chicken heads (Spring chickens (Gallus Gallus e.g. Ross 308 Broiler)), supplied by Baileys Turkeys Ltd., Cheshire, UK
- weight: 1.5 to 2.5 kg
- age: 7 weeks prior to being humanely killed for human consumption

PREPARATION OF THE EYES
Eyelids were carefully excised while taking care not to damage the cornea. The integrity of the cornea was measured usinf sodium fluorescein. An
acceptable eye for the ICE test was one where the fluorescein retention and corneal opacity scores were ≤0.5.

Acceptable eyes were dissected from the skull, enucleated eyes were transferred to an appropriate clamp keeping the cornea vertical. The temperature of the chambers was at 32 ±1.5 °C.
Eyes were examined again with a slit-lamp microscope. Corneal thickness was measured with an optical pachymeter on the slit lamp microscope at the center of each cornea. Eyes were replaced when:
i. the fluorescein score is >0.5
ii. the corneal opacity score is >0.5
iii. there is any additional signs of damage
iv. the corneal thickness measurements for individual eyes deviate more than 10% from the mean value for all eyes

Eyes were then incubated for 45 minutes for equilibrium purposes.
Time zero measurements for corneal thickness and opacity were taken to serve as a baseline. The baseline for the fluorescein measurements were taken at dissection.

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.03 mL
- Concentration (if solution): 40% (as supplied by the sponsor)

Duration of treatment / exposure:

10 seconds, then rinsed from the eye using 20 mL of isotonic saline

Observation period (in vivo):

30, 75, 120, 180 and 240 minutes (±5 minutes) after the eyes had been rinsed

Number of animals or in vitro replicates:

negative control (0.9% sodium chloride): 2
positive control (BAC 5% (w/v)): 3
test group: 3

Details on study design:

REMOVAL OF TEST SUBSTANCE - Washing (if done): 20 mL saline
- Time after start of exposure: 10 s

SCORING SYSTEM: according to ICE classification criteria OECD TG 438

TOOL USED TO ASSESS SCORE: slit lamp microscope / fluorescein

ENDPOINTS EXAMINED: corneal opacity, swelling, fluorescein retention and morphological effects (e.g. pitting, sloughing or roughening of the epithelium)

All of the endpoints, with the exception of fluorescein retention (which is only determined at 30 minutes after test substance exposure) were determined at each of the above time points.
After the final examinations at the 240 minute time point, the eyes were preserved in neutral buffered formalin, sectioned, stained ans histopathologically evaluated.

Irritation parameter:

other: corneal swelling [%]

Value:

20.09

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Irritation parameter:

cornea opacity score

Value:

2.3

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Irritation parameter:

fluorescein retention score

Value:

0.7

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Irritation parameter:

histopathological observations

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Remarks:

Serious eye damage based on corneal epithelial changes (erosion, necrosis and vacuolation of the corneal epithelium).

Irritant / corrosive response data:

Corneal Opacity
Easily discernible translucent areas or severe opacity was noted in the test item treated eyes. Very faint opacity was noted in the negative control treated eyes during the study period. Complete corneal opacity was noted in all the positive control eyes. No morphological effects were noted in the test item or negative control eyes. Sloughing (loosening of the epithelium) was noted in all the positive control eyes.

Fluorescein Retention
Very minor single cell staining or single cell staining scattered throughout the treated area of the corneas was noted on the test eyes. Very minor single cell staining was noted in one of the negative control eyes. Confluent large areas of the cornea retaining fluorescein was noted in all the positive control eyes.

Histopathology
Application of test item resulted in changes indicating serious eye damage, based on corneal epithelial changes. Changes comprised erosion, necrosis and vacuolation of the corneal epithelium. The classification was based on vacuolation being graded as ½ in the lower third of the epithelium in two out of three eyes

Test Item

Maximal mean score for corneal opacity : 2.3, ICE Class III

Mean score of Fluorescein Retention : 0.7, ICE Class II

Maximal Corneal swelling : 20.09%, ICE Class III

Positive Control Item

Maximal mean score for corneal opacity : 4.0, ICE Class IV

Mean score of Fluorescein Retention : 3.0, ICE Class IV

Maximal Corneal swelling : 52.36%, ICE Class IV

Negative Control Item

Maximal mean score for corneal opacity : 0.5, ICE Class I

Mean score of Fluorescein Retention : 0.3, ICE Class I

Maximal Corneal swelling : 3.73%, ICE Class I

Individual Scores and Mean Scores for Corneal Effects – Test Item

 

Endpoint	Eye number	Time (after washing) [min]
		0	30	75	120	180	240
Corneal Opacity	3A	0.5	0.5	2	3	3	3
	4A	0.5	0.5	1	2	2	2
	7A	0	0.5	2	2	2	2
Mean		0.3	0.5	1.7	2.3	2.3	2.3
ICE class		III
Fluorescein Retention	3A	---	0.5	---	---	---	---
	4A	---	1	---	---	---	---
	7A	---	0.5	---	---	---	---
Mean		---	0.7	---	---	---	---
ICE class		II
Corneal Thickness	3A	0.74	0.78	0.82	0.82	0.84	0.83
	4A	0.72	0.70	0.78	0.76	0.79	0.77
	7A	0.68	0.71	0.84	0.92	0.94	0.94
Mean		0.71	0.73	0.81	0.83	0.86	0.85
Mean Corneal Swelling (%)		---	2.34	14.02	16.82	20.09	18.69
ICE class		III
ICE classes combined: 2 x III, 1 x II

 

Individual Scores and Mean Scores for Corneal Effects – Positive Control Item

Endpoint	Eye number	Time (after washing) [min]
		0	30	75	120	180	240
Corneal Opacity	2A	0.5	3	4	4	4	4
	6A	0	4	4	4	4	4
	8A	0.5	4	4	4	4	4
Mean		0.3	3.7	4	4	4	4
ICE class		IV
Fluorescein Retention	2A	---	3	---	---	---	---
	6A	---	3	---	---	---	---
	8A	---	3	---	---	---	---
Mean		---	3	---	---	---	---
ICE class		IV
Corneal Thickness	2A	0.72	0.78	0.96	0.88	0.98	0.98
	6A	0.68	0.90	0.88	0.88	0.98	1.10
	8A	0.72	0.92	0.95	1.00	1.09	1.15
Mean		0.71	0.87	0.93	0.92	1.02	1.08
Mean Corneal Swelling (%)		---	22.64	31.60	30.19	43.87	52.36
ICE class		IV
ICE classes combined: 3 x IV (sloughing in all eyes)

 

Individual Scores and Mean Scores for Corneal Effects – Negative Control Item

Endpoint	Eye number	Time (after washing) [min]
		0	30	75	120	180	240
Corneal Opacity	1A	0.5	0.5	0.5	0.5	0.5	0.5
	5A	0	0.5	0.5	0.5	0.5	0.5
Mean		0.3	0.5	0.5	0.5	0.5	0.5
ICE class		I
Fluorescein Retention	1A	---	0	---	---	---	---
	5A	---	0.5	---	---	---	---
Mean		---	0.3	---	---	---	---
ICE class		I
Corneal Thickness	1A	0.67	0.66	0.68	0.70	0.69	0.70
	5A	0.67	0.66	0.65	0.69	0.68	0.66
Mean		0.67	0.66	0.67	0.70	0.69	0.68
Mean Corneal Swelling (%)		---	-1.49	-0.75	3.73	2.24	1.49
ICE class		I
ICE classes combined: 3 x I

 

 

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Based on the results from this Isolated Chicken Eye test, Amphopropionates C12-18 is considered to cause irreversible effects to the eyes under the experimental conditions described in this report.

Executive summary:

The eye irritation potential of Amphopropionates C12-18 (40% a.i.) was examined in an in vitro eye irritation study according to OECD Guideline 438 (adopted on July 26th 2013).

Approximately 7 weeks old chickens (obtained from slaughter animals for human consumption) were used as eye-donors. 0.03 mL of the test item was applied onto the cornea of each of three enucleated eyes. A further three enucleated eyes were treated with positive control item (5% (w/v) Benzalkonium Chloride (BAC)). A further two enucleated eyes were treated with saline to serve as the negative control (0.9% NaCl in water).

The isolated chicken eyes were exposed to a single application of the test sample for 10 seconds followed by a 20 mL saline rinse. Three main parameters were measured 30, 75, 120, 180 and 240 minutes after rinsing to disclose possible adverse eye effects: corneal thickness (expressed as corneal swelling), corneal opacity and fluorescein retention of damaged epithelial cells.

 

Corneal Opacity: Easily discernible translucent areas or severe opacity was noted in the test item treated eyes.

 

Fluorescein Retention: Very minor single cell staining or single cell staining scattered throughout the treated area of the corneas was noted on the test eyes.

 

Histopathology: Application of test item resulted in changes indicating serious eye damage, based on corneal epithelial changes. Changes comprised erosion, necrosis and vacuolation of the corneal epithelium. The classification was based on vacuolation being graded as ½ in the lower third of the epithelium in two out of three eyes.

 

Based on the overall in vitro irritancy criteria, no prediction for eye irritation could be made.

However, semi-quantitative microscopic evaluation of the corneas from eyes exposed to Amphopropionates C12-18 (40% a.i.) gave scores which exceeded the threshold for classification of this material as Category 1 (irreversible effects on the eyes).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

In an in vitro dermal irritation study according to OECD guideline 439, adopted July 28, 2015, Amphopropionates C12-18 (40% a.i.) was applied in triplicate (10 µL) to human skin model EpiSkin™ tissues for 15 min. Deionised water was used as negative control, 5% SLS as positive control. After exposure the skin tissues were thoroughly rinsed to remove the test substance and transferred to fresh medium.

After a 43-hour post-treatment incubation the cell viability measured by dehydrogenase conversion of MTT into a blue formazan salt was assessed as predictor for skin irritancy potential. 

After treatment with the negative control the absorbance values were well within the required acceptability criterion of mean OD ≥ 0.6 till ≤ 1.5 for the 15 minutes treatment interval thus showing the quality of the tissues. Treatment with the positive control induced a sufficient decrease in the relative absorbance as compared to the negative control for the 15 minutes treatment interval thus ensuring the validity of the test system.

The relative mean tissue viability obtained after 15 minutes treatment with the test substance compared to the negative control tissues was 102.1%. Since the mean relative tissue viability was above 50%, the test substance is considered to be non-irritant.

The positive control had a mean cell viability of 13.9% after 15 minutes exposure.

In this in vitro skin irritation test Amphopropionates C12-18 (40% a.i.) was not irritating.

 

The substance is manufactured, marketed and used only in solution at a maximum concentration of 40% a.i. No further testing on the neat substance is required, as neither worker nor consumer are exposed to the neat substance or preparations of the substance with concentrations above 40% a.i.

However, for Classification and Labelling purposes, additional supporting data obtained with the closely related source substance Amphopropionate C8 are used. A justification for read-across is given below.

In a primary dermal irritation study according to OECD guideline 404 (2002) and EU method B.4 (2004) 3 young adult male New Zealand White rabbits were dermally exposed to 0.5 g of Amphopropionate C8 (97% a.i.) for 4 hours to 6 cm² body surface area. Animals then were observed for 72 hours. Irritation was scored according to the Draize scale as stipulated in the test guideline.

No skin irritation/corrosion was caused by 4 hours exposure to Amphopropionate C8. No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred. Mean erythema and mean edema scores from observations at 24, 48 and 72 h after patch removal were 0 for 3/3 animals. In this study, Amphopropionate C8 is not irritating to skin.

 

Based on these results, also the neat substance Amphopropionates C12-18 does not require classification for skin irritation.

 

Eye irritation

The eye irritation potential of Amphopropionates C12-18 (40% a.i.) was examined in an in vitro eye irritation study according to OECD Guideline 438 (adopted on July 26th 2013).

Approximately 7 weeks old chickens (obtained from slaughter animals for human consumption) were used as eye-donors. 0.03 mL of the test item was applied onto the cornea of each of three enucleated eyes. A further three enucleated eyes were treated with positive control item (5% (w/v) Benzalkonium Chloride (BAC)). A further two enucleated eyes were treated with saline to serve as the negative control (0.9% NaCl in water).

The isolated chicken eyes were exposed to a single application of the test sample for 10 seconds followed by a 20 mL saline rinse. Three main parameters were measured 30, 75, 120, 180 and 240 minutes after rinsing to disclose possible adverse eye effects: corneal thickness (expressed as corneal swelling), corneal opacity and fluorescein retention of damaged epithelial cells.

Corneal Opacity: Easily discernible translucent areas or severe opacity was noted in the test item treated eyes.

Fluorescein Retention: Very minor single cell staining or single cell staining scattered throughout the treated area of the corneas was noted on the test eyes.

Histopathology: Application of test item resulted in changes indicating serious eye damage, based on corneal epithelial changes. Changes comprised erosion, necrosis and vacuolation of the corneal epithelium. The classification was based on vacuolation being graded as ½ in the lower third of the epithelium in two out of three eyes.

Based on the overall in vitro irritancy criteria, no prediction for eye irritation could be made.

However, semi-quantitative microscopic evaluation of the corneas from eyes exposed to Amphopropionates C12-18 (40% a.i.) gave scores which exceeded the threshold for classification of this material as Category 1 (irreversible effects on the eyes).

 

There are no data gaps for the endpoint irritation/corrosion. No human data are available. However, there is no reason to believe that these results from rabbit would not be applicable to humans.

 

Justification for read-across

For details on substance identity and detailed toxicological profiles, please refer also to the general justification for read-across given at the beginning of the CSR and attached as pdf document to IUCLID section 13.

This read-across approach is justified based on structural similarities. The target and source substances contain the same functional groups. Thus a common mode of action can be assumed.

 

Structural similarity and functional groups

The target substance Amphopropionates C12-18 is manufactured from fatty acids (C12-18, C18unsatd.) and aminoethylethanolamie (AEEA) to form 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C11-C17 odd-numbered, C17unsatd. alkyl) derivs. This is further reacted with 2-propenoic acid in the presence of sodium hydroxide (alternatively, sodium 2-propenoate can be used) and water. The molar relation between 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C11-C17, C17unsatd. alkyl) derivs. and 2-propenoic acid is somewhat below 1:1. Most of the excess 2-propenoic acid is stripped off by distillation. However, a small amount remains in the aqueous solution.

 

The source substance Amphopropionate C8 is manufactured from capric acid and aminoethylethanolamine (AEEA) to form 1-(2-Hydroxyethyl)-2-Heptylimidazoline. Excess AEEA is removed from the reaction mixture by distillation at elevated temperature. In a further step 2-propenoic acid is added to form Amphopropionate C8. Most of the excess 2-propenoic acid is stripped off by distillation. However, a small amount remains in the aqueous solution.

 

Differences

Chain length:

The source substance Amphopropionate C8 contains shorter C chains, whereas the major C chain in the target substance is C12.

In general the absorption declines with increasing alkyl chain length (Ramirez et al. 2001). Therefore the source substances with the shorter alkyl chain lengths are assumed to represent a worst-case scenario due to higher absorption rates than the target substance.

 

Degree of unsaturation:

In contrast to the source substance Amphopropionate C8, the target substance Amphopropionates C12-18 contains some amounts of unsaturated C18 chains.

An increase in the degree of unsaturation may lead to a slightly higher irritation potential (HERA, 2002; Stillman, 1975; Aungst, 1989). Apart from that, fatty acids irrespective of their degree of unsaturation are in general non-toxic. Irritation studies are available for the target substance itself.

 

The provided structural similarities and impurity profiles support the proposed read-across hypothesis with high confidence.

 

Comparison of irritation data

 

	Target substance	Source substance
Endpoint	Amphopropionates C12-18	Amphopropionate C8
Skin irritation, in vitro	key_Skin irritation / corrosion_93820-52-1_8.1_Evonik_2016_OECD439_40%   in vitro, OECD TG 439, 40% aqueous solution   102.1% cell viability   not irritating   1 (reliable without restriction), GLP	No data
Skin irritation, in vivo	No data	sup_RA_Skin irritation / corrosion_64265-45-8_8.1.1_Evonik_2007_OECD404   in vivo, OECD TG 404, neat substance (97% a.i.)   not irritating   1 (reliable without restriction), GLP

 

Amphopropionates C12 -18 (40% a.i.) was not irritating to skin in an in vitro skin irritation assay.

As the substance is manufactured, marketed and used only in solution at a maximum concentration of 40% a.i., no further testing on the neat substance is required, as neither worker nor consumer are exposed to the neat substance or preparations of the substance with concentrations above 40% a.i.

 

However, supporting data obtained with the closely related source substance Amphopropionate C8 are available: The source substance was not irritating in an in vivo skin irritation test. Erythema and mean edema scores from observations at 24, 48 and 72 h after patch removal were 0 for 3/3 animals.

 

Quality of the experimental data of the analogues:

The available data are adequate and sufficiently reliable to justify the read-across approach.

The studies were conducted according to OECD guidelines 439 and 404, respectively, and were reliable without restrictions.

The test materials used in the respective studies represent the source substance as described in the hypothesis in terms of substance identity and minor constituents.

Overall, the study results are adequate for the purpose of classification and labelling and risk assessment.

 

Conclusion

Based on structural similarities of the target and source substance as presented above and in more detail in the general justification for read-across, it can be concluded that the available data from the source substance Amphopropionate C8 are also valid for the target substance Amphopropionates C12 -18.

Neither Amphopropionates C12 -18 (40% a.i.) nor the neat substance is irritating to skin.

 

 

References

Aungst, 1989. Structure/Effect Studies of Fatty Acid Isomers as Skin Penetration Enhancers and Skin Irritants. Pharmaceutical Research, March 1989, Volume 6, Issue 3, pp 244-247

 

HERA, 2002: Fatty Acid Salts – Human Health Risk Assessment

 

Ramírez M, Amate L, Gil A. Absorption and distribution of dietary fatty acids from different sources. Early Human Development 2001 Nov; 65 Suppl:S95-S101

Stillman et al., 1975. Relative irritancy of free fatty acids of different chain length. Contact Dermatitis. 1975;1(2):65-9.

Justification for classification or non-classification

Skin irritation

Based on reliable, adequate and relevant data, Amphopropionates C12-18 does not need to be classified for skin irritation according to regulation (EC) 1272/2008.

 

Eye irritation

Based on reliable, adequate and relevant data, Amphopropionates C12-18 has to be classified as Category 1, irreversible effects on the eye according to CLP, EU GHS (Regulation (EC) No 1272/2008) and is assigned the hazard statement H318 and the signal word “Danger”.

Respiratory irritation

Based on the acrylic acid content of up to 1.5% and the specific concentration limit of >/=1% - <5%, the technical product is classified as STOT SE3/H335.