N-(2-hydroxyethyl)-N-[2-[(1-oxooctyl)amino]ethyl]-β-alanine

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

- subacute (28 d repated dose toxicity study) repeated dose toxicity study oral (gavage), rat (Wistar) m/f (OECD TG 407; GLP; RL1), dose levels: 0, 50, 150, 1000 mg/kg bw/day; NOAEL >/= 1000 mg a.i./kg bw/day; no effects on reproductive organs

Link to relevant study records

Reference

Endpoint:

reproductive toxicity, other

Remarks:

Repeated Dose 28-Day Oral Toxicity in Rodents

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Version / remarks:

1996

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)

Version / remarks:

1995

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Approximately 6 weeks.
- Weight at study initiation:
- Fasting period before study: no
- Housing: in groups of 5 per sex in Macrolon cages (M IV type, height 18 cm; during overnight activity monitoring individual housing in
Mlll type; height 15 cm) with sterilised sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment (Enviro-dri, Wm. Lilico & Son (Wonham Mill Ltd), Surrey, United Kingdom).
- Diet (e.g. ad libitum): pelleted rodent diet (SM R/M-Z from SSNlFF Spezialdiaten GmbH, Soest, Germany), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.4 - 22.7°C
- Humidity (%): 30 - 74%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was administered undiluted.

Details on mating procedure:

animals were not mated

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily, 7 days a week

Details on study schedule:

animals were not mated

Dose / conc.:

50 mg/kg bw/day (actual dose received)

Dose / conc.:

150 mg/kg bw/day (actual dose received)

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

5

Control animals:

other: yes, from day 15 onwards Milli-Q water was used

Details on study design:

- Dose selection rationale: The dose levels were selected on the basis of a 5-day dose range finding study
- Rationale for animal assignment: By computer-generated random algorithm according to body weight

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean weekly diet consumption calculated as g food/kg body weight/day

WATER CONSUMPTION: subjective appraisal was maintained during the study, but no quantitative investigation introduced as no effect was suspected.

OTHER: presented in more detail in section "repeated dose toxicty"
HAEMATOLOGY, CLINICAL CHEMISTRY, NEUROBEHAVIOURAL EXAMINATION

Oestrous cyclicity (parental animals):

not examined

Sperm parameters (parental animals):

not examined

Litter observations:

n.a.

Postmortem examinations (parental animals):

GROSS PATHOLOGY: Yes, all animals assigned to the study
ORGAN WEIGHTS: Yes, presented in more detail in section "repeated dose toxicity"
HISTOPATHOLOGY: Yes, presented in more detail in section "repeated dose toxicity"

Postmortem examinations (offspring):

n.a.

Reproductive indices:

n.a.

Offspring viability indices:

n.a.

Clinical signs:

no effects observed

Description (incidence and severity):

There were no clinical signs of toxicity noted over the 28-day observation period.
Salivation as observed among all animals at 1000 mg/kg bw/day and three males at 150 mg/kg bw/day was considered to be of no toxicological significance taking into account the nature and minor severity of this finding. Instead, salivation was considered to be a physiological response to taste and/or irritancy of the test substance upon oral administration.
Alopecia of the forelegs of one male at 50 mg/kg bw/day was a sign within the range of findings encountered in this type of study and was of no toxicological relevance. No clinical signs were noted among control animals, and females at 50 and 150 mg/kg bw/day.

Mortality:

no mortality observed

Description (incidence):

No mortality occurred during the study period.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No toxicologically significant changes in body weights and body weight gain of treated animals were noted.
The slightly lower body weight and body weight gain of males at 1000 mg/kg bw/day in the first week of treatment (achieving a level of statistical significance for body weights) was considered to be of no toxicological significance. The change was of a temporary and slight nature (i.e. within the range considered normal for rats of this age and strain).

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Food consumption before or after allowance for body weight was similar between treated and control animals.

Food efficiency:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

There were no microscopic findings recorded which could be attributed to treatment with the test substance.
All microscopic findings were within the range of background pathology encountered in Wistar rats of this age and strain and occurred at similar incidences and severity in both control and treated rats.

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

not examined

OTHER FINDINGS (PARENTAL ANIMALS)
further results are presented in more detail in section "repeated dose toxicity"

Dose descriptor:

NOAEL

Remarks:

fertility paramaters

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: no treatment-related effects up to and including the highest administered dose

Critical effects observed:

no

Clinical signs:

not examined

Mortality / viability:

not examined

Body weight and weight changes:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings:

not examined

Reproductive effects observed:

no

Conclusions:

On the basis of the results obtained in this study, the dose level of 1000 mg/kg bw/day was considered the NOAEL for general toxicity and for fertility parameters.

Executive summary:

In this Repeated Dose, 28-day Oral Toxicity Study performed according to OECD guideline 407 (1995) and EU Method B.7 (1996) Amphopropionate C8  (50.6 % a.i) was administered to groups of 5 male and 5 female Wistar rats by oral gavage at dose levels of 10, 150 and 1000 mg/kg bw/day for 28 days. The control group animals received MilliQ water from day 15 onwards.

All animals survived to study termination. No test substance-related findings were detected or observed in clinical examinations, body weights, food consumption values, neurobehaviour, haematology, clinical biochemistry and clinical pathology evaluations. During the anatomical pathology examinations, no test substance-related findings were observed or detected during macroscopic examinations, organ weight evaluations or microscopic examinations. In specific, no effects were noted on reproductive organs examined in this study.

There is no evidence for specific target organ toxicity in this study.

The NOAEL is ≥ 1000 mg/kg bw/day in this study.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

OECD guideline study, GLP, RL1

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

For the assessment of reproduction toxicity, relevant and reliable data from oral subacute repeated dose toxicity study with additional focus on reproductive organs are available.

 

In a Repeated Dose, 28-day Oral Toxicity Study performed according to OECD guideline 407 (1995) and EU Method B.7 (1996) Amphopropionate C8  (50.6 % a.i) was administered to groups of 5 male and 5 female Wistar rats by oral gavage at dose levels of 250, 500 and 1000 mg test material/kg bw/day for 28 days. The control group animals received MilliQ water from day 15 onwards.

All animals survived to study termination. No test substance-related findings were detected or observed in clinical examinations, body weights, food consumption values, neurobehaviour, haematology, clinical biochemistry and clinical pathology evaluations. During the anatomical pathology examinations, no test substance-related findings were observed or detected during macroscopic examinations, organ weight evaluations or microscopic examinations. In specific, no effects were noted on reproductive organs examined in this study. There is no evidence for specific target organ toxicity in this study. The NOAEL is ≥ 1000 mg/kg bw/day in this study.

 

In accordance with Annex VIII, 8.7.1, column 2 of the REACH Regulation (EC) No 1907/2006, a screening test for reproductive/ developmental toxicity does not need to be conducted if a pre-natal developmental toxicity study (Annex IX, 8.7.2) is available.A prenatal developmental toxicity study with a closely related substance is proposed.

 

Supporting data are available for Acrylic acid, demonstrating that the presence of small amounts (0 – 1%) of acrylic acid in the target substance is of no toxicological relevance:

According to EU RAR (2002), in “oral reproductive toxicity studies (rats) no effects on reproductive function (fertility) were observed.” And a “NOAEL/fertility of 460 mg/kg bw/d was derived from a guideline 2-generation study in rats”.

 

No human information is available for this endpoint. However, there is no reason to believe that these results would not be applicable to humans.

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available (further information necessary)

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In accordance with Annex VIII, 8.7.1, column 2 of the REACH Regulation (EC) No 1907/2006, a screening test for reproductive/ developmental toxicity does not need to be conducted if a pre-natal developmental toxicity study (Annex IX, 8.7.2) is available. A prenatal developmental toxicity study with a closely related substance is proposed.

In the Amphoacetates C8-C18 (EC number:931-291-0) dossier, which has already been submitted to ECHA, a prenatal developmental toxicity study in the rat according to OECD guideline 414, testing by oral route, is proposed. A read-across from this study will be used to cover the endpoint prenatal developmental toxicity (REACH Regulation, Annex IX, 8.7.2).

As soon as study data are available, a robust study summary will be prepared and submitted within an update of the dossier. Evaluation will be reconsidered based on the outcome of the prenatal developmental toxicity study.

In conclusion, a prenatal developmental toxicity study will be conducted with the closely related source substance Amphoacetates C8-C18. Hence, a further testing proposal for a prenatal developmental toxicity study with the target substance itself is considered not justified. A justification for read-across is given below.

 

Supporting data are available for Acrylic acid, demonstrating that the presence of small amounts (0 – 1%) of acrylic acid in the target substance is of no toxicological relevance: According to EU RAR (2002), no “prenatal developmental toxicity was observed (rats and rabbits, inhalation), even at concentration levels that produced some signs of maternal toxicity. No specific teratogenic potential could be revealed for dose levels up to and including 360 ppm (rats), resp. 225 ppm (rabbits). A NOAEL/developmental toxicity of 225 ppm (according to 663 mg/m³) was derived from the developmental toxicity study in rabbits”. Acrylic acid is not classified as toxic to reproduction.

 

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 and a comparable toxicological profile based on the available data. 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 Amphopropionate C8 is manufactured from capric acid andaminoethylethanolamie (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.

 

The source substance Amphoacetates C8-C18 is manufactured from 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C7-C17 odd-numbered, C17-unsatd. alkyl) derivs. and chloroacetic acid in the presence of sodium hydroxide. The molar relation between 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C7-C17 odd-numbered, C17-unsatd. alkyl) derivs. and chloroacetic acid ranges from 1:1 to 1:2. As by-product, hydrochloric acid is formed during the reaction, that is neutralized with adding more sodium hydroxide.

 

Differences

Chain length:

The target substance Amphopropionate C8 contains C8 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). Thus, the target substance may be bioavailable to a slightly higher degree.

 

Degree of unsaturation:

In contrast to the target substance Amphopropionate C8, the source substance Amphoacetates C8-C18 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.

Propionate vs. acetate functions:

The target substance Amphopropionate C8 contains propionate functions, whereas the source substance Amphoacetates C8-C18 contains acetate functions. The shorter acetate chains might lead to slightly higher absorption.

 

Presence of residual acrylic acid:

The target substance Amphopropionate C8 may contain some small amounts of residual acrylic acid, in contrast to the source substance Amphoacetates C8-C18.

However, supporting data from acrylic acid demonstrate that this difference in composition is of no toxicological relevance for human health endpoints.

 

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.

As genotoxicity is one possible mechanism for developmental toxicity, the negative outcome of the genotoxicity tests for the target and source substance further supports the read-across. Genotoxicity is based on covalent binding of the substance itself or reactive metabolites to cellular macromolecules as rate determining step.

There are no indications for a classification for developmental toxicity and teratogenicity at this time.

Evaluation will be reconsidered based on the outcome of the prenatal developmental study with the source substance Amphoacetates C8-C18.

 

 

References

EU RAR, 2002: European Union, Risk Assessment Report: Acrylic acid, CAS No: 79-10-7, Risk Assessment. European Union Risk Assessment Report, 1st Priority List, Vol. 2

 

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

Justification for classification or non-classification

Based on the available data, Amphopropionate C8 does not have to be classified for toxicity to reproduction according to Regulation (EC) No 1272/2008. Evaluation will be reconsidered based on the outcome of the prenatal developmental toxicity study with the source substance Amphoacetates C8-C18.