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

Oral LD50 > 2000 mg a.i./kg bw; OECD TG 423 / Method B.1, rat; oral: gavage; RL1, GLP
Dermal LD50 > 2000 mg a.i./kg bw; OECD TG 402 / Method B.1, rat; RL1, GLP; read-across: Amphopropionate C8
Inhalation: no relevant route of exposure

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-08-18 to 2015-09-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

17 December 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 147-183 g
- Fasting period before study: overnight
- Housing: in groups of three in suspended solid-floor polypropylene cages furnished with woodflakes
- Diet (e.g. ad libitum): ad libitum (2014C Teklad Global Rodent diet supplied by Envigo RMS (UK) Limited, Oxon, UK)
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25°C
- Humidity (%): 30-70%
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 4.88 mL/kg

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: In the absence of data regarding the toxicity of the test item, 750 mg/kg (equivalent to 300 mg
active ingredient/kg body weight) was chosen as the starting dose.

Doses:

750 mg/kg (equivalent to 300 mg a.i. /kg)
5000 mg/kg (equivalent to 2000 mg a.i./kg)

No. of animals per sex per dose:

3 females in the 750 mg/kg (equivalent to 300 mg a.i. /kg) group
2x3 females in the 5000 mg/kg (equivalent to 2000 mg a.i./kg) group

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The animals were observed for deaths or overt signs of toxicity 30 minutes, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days. Individual body weights were recorded prior to dosing and 7 and 14 days after treatment.
- Necropsy of survivors performed: yes

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Mortality:

none

Clinical signs:

other: No signs of systemic toxicity were noted during the observation period.

Gross pathology:

No abnormalities were noted at necropsy.

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral LD50 of Amphopropionates C12 -18 in female Wistar rats was estimated to be greater than 2000 mg a.i./kg bw).

Executive summary:

In an acute oral toxicity study according to OECD Guideline 423 (2001) and EU Method B1., groups of three fasted female young adult Wistar rats were given a single oral dose of Amphopropionates C12 -18 (40% a.i.) at doses of 300 and 2000 mg a.i./kg bw and were observed for 14 days.

No mortality occurred and no signs of systemic toxicity were observed.

Oral LD50 females > 2000 mg a.i./kg bw

Based on these results, Amphopropionate C12 -18 does not have to be classified and has no obligatory labelling requirement for acute oral toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Guideline study without deviations; RL1; GLP

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2007-05-09 to 2007-05-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

1987

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Young adult animals (approx. 8 weeks old)
- Weight at study initiation: Body weight variation did not exceed +/- 20% of the sex mean.
- Fasting period before study: none
- Housing: Individually housed in labeled Macrolon cages (MIII type, height 18 cm.) containing sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage­enrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom).
- Diet (e.g. ad libitum): Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiaten GmbH, Soest, Germany).
- Water (e.g. ad libitum): Free access to tap water.
- Acclimation period: Acclimatization period was at least 5 days before start of treatment under laboratory conditions. During the acclimatization period the animals were group housed in Macrolon cages (MIV type).

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.8 - 23.0°C
- Humidity (%): 39 - 70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 09 May 2007 To: 23 May 2007

Type of coverage:

occlusive

Vehicle:

water

Details on dermal exposure:

TEST SITE
- Area of exposure: 5x7 cm
- % coverage: 10%
- Type of wrap if used: The test substance was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1 D), successively covered with aluminum foil and Caban elastic bandage. A piece of Micropore tape was additionally used for fixation of the bandages in females only

REMOVAL OF TEST SUBSTANCE
24 hours after application the dressings were removed and the skin cleaned of residual test substance using tap water

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 3738 mL/kg; 2024 mg a.i./kg bw
- Concentration (if solution): 50.6%
- Constant volume or concentration used: yes

Duration of exposure:

24 hours

Doses:

2024 mg a.i./kg bw

No. of animals per sex per dose:

5 males and 5 females

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Mortality: Twice daily; Body weights: Days 1 (pre-administration), 8 and 15; clinical signs: At periodic intervals on the day of dosing (Day 1) and once daily thereafter, until Day 15
- Necropsy of survivors performed: yes

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Mortality:

No mortality occurred.

Clinical signs:

other: Lethargy, flat posture, piloerection (head), chromodacryorrhoea (snout) and/or ptosis was noted among the animals. The animals had recovered from the symptoms between Days 2 and 3. Focal erythema, scars, scales and/or scabs were seen in the treated skin-

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Interpretation of results:

GHS criteria not met

Conclusions:

The dermal LD50 value of Amphopropionate C8 in Wistar rats was established to exceed 2000 mg a.i./kg body weight.

Executive summary:

In an acute dermal toxicity study according to OECD guideline 402 (1987) and EU Method B.3 (1992), groups of young adult Wistar rats (5 males and 5 females) were dermally exposed to Amphopropionate C8 (50.6% a.i.) for 24 hours to the limit dose of  2024 mg a.i./kg bw.  Animals then were observed for 14 days.

No mortality occurred. Lethargy, flat posture, piloerection (head), chromodacryorrhoea (snout) and/or ptosis was noted among the animals. The animals had recovered from the symptoms between Days 2 and 3. Focal erythema, scars, scales and/or scabs were seen in the treated skin-area of the females during the observation period.

 

Dermal LD50 Males    > 2000 mg/kg bw

                    Females > 2000 mg/kg bw

         

Based on these results, Amphopropionate C8 does not have to be classified and has no obligatory labelling requirement for dermal toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Guideline study without deviations; RL1; GLP

Additional information

Acute oral toxicity

In an acute oral toxicity study according to OECD Guideline 423 (2001) and EU Method B.1, groups of three fasted female young adult Wistar rats were given a single oral dose of Amphopropionates C12 -18 (40% a.i.) by gavage at doses of 300 and 2000 mg a.i./kg bw and were observed for 14 days. No mortality occurred and no signs of systemic toxicity were observed.

Oral LD50 females > 2000 mg a.i./kg bw

 

In an acute oral toxicity study similar to OECD Guideline 401 (study performance before implementation of OECD TG 401(1981) and GLP), 5 male and 5 female Sprague Dawley SPF albino rats weighing 100 - 120 g were given a single oral dose of Amphopropionates C12 -18 (40% a.i.) at a concentration of 16 mL/kg bw and observed for 14 days. The test substance was administered by gavage and undiluted.

Four of ten animals died. No effects on body weights were observed. Hunched position, rough fur, paleness of extremities, diarrhea, increased lacrimation, slight lethargy and ataxia were observed. Gross pathological examinations at 14 days p.a. (terminal necropsy) revealed a moderate hyperemia, mild haemorrhagic oedema of the lungs, moderate hyperemia of the liver and a local swelling of the cutaneous gastric mucosa.

Oral LD50 Males and Females > 6611 mg/kg bw

(> 16 mL/kg bw; based on product, recalculated with a density 1.033 g/mL and a solid content of 40 %).

 

Similar results were obtained with the closely related source substances Amphopropionate C8 and Amphoacetates C8-C18. These data are included into the dossier for the justification of read-across for other endpoints.

 

In an acute oral toxicity study according to OECD Guideline 423 (2002) and EU Method B1., two groups of three fasted female young adult Wistar rats were given a single oral dose of Amphopropionate C8 (50.6% a.i.) at the limit dose 2024 mg a.i./kg bw and were observed for14 days. No mortality occurred. Hunched posture was noted among the animals on Day 1.

Oral LD50 females > 2000 mg a.i./kg bw

 

The LD50 of Amphoacetates C8-C18 in rat was in the range of 34 - 44.5 ml/kg (aqueous solution) in several studies similar to OECD Guideline 401 (performed before implementation of OECD TG 401(1981) and GLP).

 

Acute inhalation toxicity

Given that inhalation is not a relevant route of exposure, testing by the inhalation route is not necessary according to REACH Regulation Annex VIII 8.5.2 Column 2. Inhalation is not a relevant route of exposure to Amphopropionates C12-18. This applies to both workers and the general population and is due to the physic-chemical properties of the substance and the nature of the products where it is used. Vapourisation needs not to be considered due to the substance’s very low vapour pressure of 8E-21 Pa at 25°C. The generation of aerosols is excluded by technical means or product design. The substance is not used in spray applications. The most likely route of human exposure for workers and consumers is the dermal route. Results of laboratory animal studies show a low acute toxicity after oral exposure. Therefore the acute intrinsic toxic activity of the substance is considered to be low. The occurrence of a systemic toxicity relevant to humans after inhalation is unlikely and therefore the conduct of an acute inhalation toxicity study is unjustified.

 

Acute dermal toxicity

According to a Draft Commission Regulation amending Annexes VII and VIII to Regulation (EC) No 1907/2006 (Reference: G/TBT/N/EU/317) testing by the dermal route does not need to be conducted if the substance does not meet the criteria for classification as acutely toxic or STOT SE by the oral route and no systemic effects have been observed inin vivostudies with dermal exposure (e.g. skin irritation, skin sensitisation).

Amphopropionates C12-18 have a low acute oral toxicity (LD50 > 2000 mg/kg bw), and there were no indications for systemic toxicity in other studies with dermal application (in vivo skin irritation and sensitisation studies).

 

Supporting data are available from the closely related source substance Amphopropionate C8. A justification for read-across is given below.

 

In an acute dermal toxicity study according to OECD guideline 402 (1987) and EU Method B.3 (1992), groups of young adult Wistar rats (5 males and 5 females) were dermally exposed to Amphopropionate C8 (50.6% a.i.) for 24 hours to the limit dose of 2024 mg a.i./kg bw.  Animals then were observed for 14 days.

No mortality occurred. Lethargy, flat posture, piloerection (head), chromodacryorrhoea (snout) and/or ptosis was noted among the animals. The animals had recovered from the symptoms between Days 2 and 3. Focal erythema, scars, scales and/or scabs were seen in the treated skin-area of the females during the observation period.

 Dermal LD50 Males    > 2000 mg/kg bw

                   Females > 2000 mg/kg bw

         

 

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 substance with the shorter alkyl chains is re 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, thus, for other endpoints,this difference in composition is of no toxicological relevance.

 

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

 

Comparison of acute toxicity data

 

	Target substance	Source substance
Endpoint	Amphopropionates C12-18	Amphopropionate C8
Acute toxicity, oral	key_Acute toxicity: oral_93820-52-1_8.5.1_Evonik_2015_OECD423   OECD TG 423, rat (Wistar), oral: gavage   LD50(females) > 2000 mg a.i./kg bw   1 (reliable without restriction), GLP	sup_RA_Acute toxicity_64265-45-8_8.5.1_Evonik_2007_OECD423   OECD TG 423, rat (Wistar), oral: gavage   LD50(females) > 2000 mg a.i./kg bw   1 (reliable without restriction), GLP
	sup_Acute toxicity: oral: 93820-52-1_8.5.1_REWO_1979_LD 50 oral   similar to OECD TG 401, rat (Sprague-Dawley), oral: gavage   LD50 > 6611 mg a.i./kg bw   2 (reliable with restrictions), pre-GLP
Acute toxicity, dermal	No data, read-across	sup_RA_Acute toxicity_64265-45-8_8.5.3_Evonik_2007_OECD402   OECD TG 402, rat (Wistar), type of coverage: occlusive   LD50 > 2000 mg a.i./kg bw   1 (reliable without restriction), GLP

 

The acute oral LD50 of Amphopropionates C12 -18 in female Wistar rats was > 2000 mg a.i./kg bw). The source substance Amphopropionate C8 was of similarly low acute toxicity via the oral route.

No experimental data on acute dermal toxicity are available for the target substance. However, in an acute dermal toxicity study Amphopropionate C8 the dermal LD50 was > 2000 mg/kg bw/d.

 

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 423 and 402, respectively, or similar to OECD Guideline 401, and are reliable or reliable with restrictions (RL1-2).

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

The structural similarities between the source and the target substances presented above and in more detail in the general justification for read-across support the read-across hypothesis. Adequate and reliable scientific information indicates that the source and target substances have similar toxicity profiles for the endpoint acute toxicity based on the similarly low acute toxicity via the oral route.

Thus, the results obtained with the source substance Amphopropionate C8 in the acute dermal toxicity study are considered to be also relevant for the target substance Amphopropionates C12 -18.

 

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

Based on the available data, Amphopropionates C12 -18 does not have to be classified and has no obligatory labelling requirement for acute oral, dermal or inhalation toxicity according to Regulation (EC) No 1272/2008).