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

- subacute (28 d repeated 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; read-across: Amphopropionate C8
- subacute (28 d repeated dose toxicity study) repeated dose toxicity study oral (gavage), rat (Sprague-Dawley) m/f (similar to OECD TG 407; no GLP; RL2), dose levels: 0, 250, 500, 1000 mg/kg bw/day as test material; NOAEL = 250 mg/kg bw/d, corresponding to 92.5 mg a.i./kg bw/d; read-across: Amphoacetates C8-C18

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2007-05-02 to 2007-05-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1996

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1995

Deviations:

no

GLP compliance:

yes

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: 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

IN-LIFE DATES:
Main study: From 02 May 2007 To: 30 May 2007

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

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

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily, 7 days a week

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

Observations and examinations performed and frequency:

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.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: immediately prior to scheduled postmortem examination
- Anaesthetic used for blood collection: Yes, iso-flurane
- Animals fasted: Yes, overnight (with a maximum of 20 hours)
- How many animals: all
- Parameters examined: White blood cells, Differential leucocyte count (neutrophils, lymphocytes, monocytes, eosinophils, basophils), Red blood cells, Reticulocytes, Red blood cell distribution width, Haemoglobin, Haematocrit, Mean corpuscular volume, Mean corpuscular haemoglobin, Mean corpuscular haemoglobin concentration, Platelets, Prothrombin time, Activated Partial thromboplastin time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: immediately prior to scheduled postmortem examination
- Animals fasted: Yes, overnight (with a maximum of 20 hours)
- How many animals: all
- Parameters examined: Alanine aminotransferase, Aspartate aminotransferase, Alkaline phosphatase, Total Protein, Albumin, Total Bilirubin, Urea, Creatinine, Glucose, Cholesterol, Sodium, Potassium, Chloride, Calcium, Inorganic Phosphate

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes, functional observations
- Time schedule for examinations: during week 4 of treatment
- Dose groups that were examined: all
- Battery of functions tested:
a. hearing ability (HEARING), pupillary reflex (PUPIL L/R), static righting reflex (STATIC R) and grip strength (GRIP) (Score 0 = normal/present, score 1 = abnormal/absent).
b. motor activity test (recording period: 12 hours during overnight for individual animals, using a computerised monitoring system, Pearson Technical Services, Debenham, Stowmarket, England).

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, all animals assigned to the study
ORGAN WEIGHTS: Yes, see table 1
HISTOPATHOLOGY: Yes, see table 1

Statistics:

The following statistical methods were used to analyse the data:
- If the variables could be assumed to follow a normal distribution, the Dunnett-test (many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups for each sex.
- The Steel-test (many-to-one rank test) was applied when the data could not be assumed to follow a normal distribution.
- The exact Fisher-test was applied to frequency data.
All tests were two-sided and in all cases p < 0.05 was accepted as the lowest level of significance. Group means were calculated for continuous data and medians were calculated for discrete data (scores) in the summary tables. Test statistics were calculated on the basis of exact values for means and pooled variances. Individual values, means and standard deviations may have been rounded off before printing. Therefore, two groups may display the same printed means for a given parameter, yet display different test statistics values.

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

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

No toxicologically relevant changes occurred in haematological parameters of treated rats.
No toxicological significance was ascribed to the statistically significant lower haemoglobin levels in males at 150 and 1000 mg/kg bw/day and lower mean corpuscular haemoglobin concentration levels (MCHC) in males at 50 mg/kg bw/day, as these alterations were of a minor nature and occurred in the absence of a dose-related trend.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

Clinical biochemistry parameters of treated rats were considered not to have been affected by treatment.
Any statistically significant changes noted among the dose groups were considered not to represent a sign of toxicity as these changes were of a minor nature and occurred in the absence of a dose-related trend. These alterations included lower alkaline phosphatase activity (ALP) and higher glucose levels in males at 50 mg/kg bw/day, lower cholesterol levels in males at 50 mg/kg bw/day and higher (a similar variation in this parameter was also noted among female dose groups), higher sodium and lower calcium levels in males at 150 mg/kg bw/day, and lower inorganic phosphate levels in females at 50 and 1000 mg/kg bw/day.

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

Hearing ability, pupillary reflex, static righting reflex and grip strength were normal in all animals. The variation in motor activity did not indicate a relation with treatment.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No toxicologically significant changes were noted in organ weights and organ to body weight ratios.
The statistically significant lower brain weight of males at 1000 mg/kg bw/day was of a very minor nature (i.e. well within the range considered normal for rats of this age and strain). Also, brain weights of these males were similar to controls when corrected for terminal body weight. Therefore, this alteration was considered to be of no toxicological significance.

Gross pathological findings:

no effects observed

Description (incidence and severity):

Necropsy did not reveal any toxicologically relevant alterations.
Incidental findings included a diaphragmatic hernia of the right lateral lobe of the liver in one male (no. 19) at 1000 mg/kg bw/day (this correlated to a high ASAT level in this male), fluid in the uterus in one female at 50 and 1000 mg/kg bw/day, and a yellowish focus on the left median lobe of the liver with enlargement of the mandibular lymph node in one female at 1000 mg/kg bw/day. These findings are occasionally seen among rats used in these types of studies. In the absence of a treatment-related distribution they were considered changes of no toxicological significance.
No macroscopic abnormalities were noted in control animals, in males at 50 and 150 mg/kg bw/day, and in females at 150 mg/kg bw/day.

Neuropathological findings:

not examined

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.

Histopathological findings: neoplastic:

not examined

Dose descriptor:

NOAEL

Effect level:

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

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: overall effects

Critical effects observed:

no

Conclusions:

No toxicologically significant changes were noted in any of the parameters examined/determined in this study (i.e. clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination.
Therefore a definitive No Observed Adverse Effect Level (NOAEL) for Amphopropionate C8 of 1000 mg/kg bw/day was established.

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.

 

Reference 2

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

July 5, 1988 - January 16, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Not completely according to the current version of OECD 407. Although no Functional observational battery (FOB) observations, all other parameters are included. The test material was not administered daily, but 5 times per week (Monday-Friday). Not GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

no

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS (SPF quality)
- Source: Charles River wiga, Sulzfeld
- Age at study initiation: 4 weeks
- Weight at study initiation: 68 - 90 g (male) and 64 - 86 g (female)
- Fasting period before study: Not applicable
- Housing: 2 - 3 rats per Makrolon cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 10 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-23 degrees Celsius
- Humidity (%): 51 - 64%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

IN-LIFE DATES: no data

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

The animals were all dosed with 10 ml/kg bw. Depending on the dose, the concentration of the testmaterial in the dose was either 0, 2.5, 5 or 10%.

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Not applicable

Duration of treatment / exposure:

28 days

Frequency of treatment:

5 times per week (Monday-Friday)

Dose / conc.:

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

Remarks:

based on test material

Dose / conc.:

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

Remarks:

based on test material

Dose / conc.:

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

Remarks:

based on test material

No. of animals per sex per dose:

10 male and 10 female per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- 100 rats (50 male and 50 female) were used in total.
- 80 rats for the main groups (control and the 3 doses) and 20 rats for the satellite groups
- Post-exposure recovery period in satellite groups: 14 days
- Satellite groups:
1) 0 mg/kg bw/day: 5 male and 5 female rats
2) 1000 mg/kg bw/day: 5 male and 5 female rats

Positive control:

Not applicable

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes, 2 times daily
DETAILED CLINICAL OBSERVATIONS: No
BODY WEIGHT: Yes, weekly
HAEMATOLOGY: Yes, at the end of the test period, for main groups only, see below for the examined parameters.
CLINICAL CHEMISTRY: Yes, at the end of the test period, for main groups only, see below for the examined parameters
URINALYSIS: No
NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, at the end of the test period, for both the 4 main and 2 satellite groups.
HISTOPATHOLOGY: Yes, at the end of the test period, for the entire control group and for the entire group with the highest dose received.

Other examinations:

Food consumption: weekly/group
Water consumption: weekly/group
Opthalmoscopy: at the end of the test period, for the entire control group and for the entire group with the highest dose received.

Statistics:

- t-Test for determination of significant inter-group difference, for body weight and biochemical examinations: L. Sachs, Statistische Auswertungsmethoden, 3. Auflage, S. 11, 212, Springer-Verlag, Berlin, 1971
- t-Test for determination of significant inter-group difference, for biochemical and hematological examinations:
1) C.W. Dunnett, 1955: A Multiple Comparison Procedure for comparing several treatments with a control, Journal of the American Statistical Association, Dec. 1955, Vol. 372, 1096-1121
2) C.W. Dunnett, 1964: New tables for multiple comparisons with a control, Biometrics, 1964, 482-490
- U-test for the determination of significant inter-group difference, for organ weights: L. Sachs, Statistische Auswertungsmethoden, 3. Auflage, S. 172, 230-236, Springer-Verlag, Berlin, 1971

Clinical signs:

no effects observed

Description (incidence and severity):

No substance-related observations compared to controls

Mortality:

no mortality observed

Description (incidence):

No substance-related observations compared to controls

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No significant substance-related effects compared to controls

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No significant substance-related effects compared to controls

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

no effects observed

Description (incidence and severity):

No significant substance-related effects compared to controls

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No significant substance-related effects compared to controls

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Statistically significant observations:
Females given 250, 500 and 1000 mg/kg bw/day showed a significant increase of thrombocytes of 114, 115 and 116%, respectively. These changes are not considered toxicological relevant, since values were within normal ranges and because of the absence of further changes in haematology. Changes were probably due to incidental low control values.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

Statistically significant observations:
Male rats given 250, 500 or 1000 mg/kg bw/day showed a significant decrease in GGT (26, 28 and 17% of controls, respectively).
This finding is not considered toxicological relevant, since it was accompanied by other changes in clinical biochemistry in males (e.g. AP, Bili.) and since a decrease was measured, instead of a more toxicological relevant increase.

Female rats given 500 or 1000 mg/kg bw/day showed a significant decrease in GOT of 85% and 78% of controls, respectively. Since a decrease was measured, this finding is considered not toxicological relevant; furthermore, since no histopathological changes in liver were observed.

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Statistically significant observations:
In females, at 250, 500 and 1000 mg/kg bw/day, a significant increase in absolute liver weight was noted (110, 121 and 121% of controls, respectively). Relative liver weights were also significant increased in all dose groups (104, 109 and 112% of controls, respectively). Although no histopathological changes were noted in liver, an increase in liverweight of >10% in absence of further changes in a sub-acute toxicity study, should be considered toxicological relevant (Reference: TNO report V2524, 2000).

Gross pathological findings:

no effects observed

Description (incidence and severity):

No significant substance-related observations

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No significant substance-related observations

Histopathological findings: neoplastic:

not examined

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

organ weights and organ / body weight ratios

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

act. ingr.

Remarks:

(solid content)

Sex:

female

Basis for effect level:

other: The solid content of the testmaterial is 37%. The NOAEL based on the testmaterial is 250 mg/kg bw/day. Calculation: 250 x 0.37 = 92.5 mg/kg bw/day (NOAEL based on the solid content of the substance)

Dose descriptor:

LOAEL

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

organ weights and organ / body weight ratios

Dose descriptor:

LOAEL

Effect level:

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

Based on:

act. ingr.

Remarks:

(solid content)

Sex:

female

Basis for effect level:

other: The solid content of the testmaterial is 37%. The LOAEL based on the testmaterial is 500 mg/kg bw/day. Calculation: 500 x 0.37 = 185 mg/kg bw/day (LOAEL based on the solid content of the substance)

Critical effects observed:

yes

Lowest effective dose / conc.:

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

System:

hepatobiliary

Organ:

liver

Treatment related:

yes

Conclusions:

NOAEL: 250 mg/kg bw/day (aqueous solution at 37%);
NOAEL: 92.5 mg/kg bw/day

Endpoint conclusion

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 without deviations, RL1, GLP

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

No experimental data are available for the target substance Amphopropionates C12-18. However, relevant and reliable data from oral subacute repeated dose toxicity studies conducted with the closely related source substances Amphopropionate C8 and Amphoacetates C8-C18 are available. A justification for read-across is given below.

 

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 a Repeated Dose, 28-day Oral Toxicity Study performed similar to OECD guideline 407 Amphoacetates C8-C18  (37 % a.i) was administered to groups of 10 male and 10 female Sprague-Dawley rats by oral gavage at dose levels of 0 (control), 10, 150 and 1000 mg/kg bw/day for 28 days on 5 times per week (Monday-Friday).

No significant effects on clinical signs, body weight, body weight gain, food and water consumption  were observed in this study. During ophthalmoscopic examination, no significant substance-related effects compared to controls were noted. No significant substance-related observations were made during macroscopic examinations or microscopic examinations.

Females given 250, 500 and 1000 mg/kg bw/day showed a significant increase of thrombocytes of 114, 115 and 116%, respectively. These changes are not considered toxicological relevant, since values were within normal ranges and because of the absence of further changes in haematology. Changes were probably due to incidental low control values.

Male rats given 250, 500 or 1000 mg/kg bw/day showed a significant decrease in GGT (26, 28 and 17% of controls, respectively).

This finding is not considered toxicological relevant, since it was accompanied by other changes in clinical biochemistry in males (e.g. AP, Bili.) and since a decrease was measured, instead of a more toxicological relevant increase.

Female rats given 500 or 1000 mg/kg bw/day showed a significant decrease in GOT of 85% and 78% of controls, respectively. Since a decrease was measured, this finding is considered not toxicological relevant; furthermore, since no histopathological changes in liver were observed.

In females, at 250, 500 and 1000 mg/kg bw/day, a significant increase in absolute liver weight was noted (110, 121 and 121% of controls, respectively). Relative liver weights were also significant increased in all dose groups (104, 109 and 112% of controls, respectively). Although no histopathological changes were noted in liver, an increase in liverweight of >10% in absence of further changes in a sub-acute toxicity study, may be considered toxicologically relevant.

The NOAEL based on an increase in liver weights was 250 mg/kg bw/day (aqueous solution at 37%), corresponding to 92.5 mg a.i./kg bw/day.

 

However, as only females showed an increase in liver weights and, moreover, no such changes were observed in the 28 d study with the source substance Amphopropionate C8, the overall NOAEL for the target substance Amphopropionates C12-18 based on weight-of-evidence is set at 1000 mg/kg bw/d.

 

The conduct of a subchronic 90 d repeated dose toxicity study is proposed within this dossier. The dossier will be updated and evaluation will be reconsidered based on the outcome of the study.

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) “the toxic profile of acrylic acid is dominated by its local irritation effects irrespective of the way of application. Prolonged inhalation of concentrations from 5 ppm or higher in mice and 75 ppm in rats induced degeneration of the olfactory mucosa. It causes severe mucosal damage to the stomach after repeated gavage administration of >150 mg/kg bw/d, but not after application via drinking water at similar or higher doses. Long-term exposure of the skin to acrylic acid at a concentration of >1% resulted in irritation whereas no effect on the skin was evident at 1% (see also dermal carcinogenicity studies in Section 4.1.2.8). Following oral, dermal or inhalation administrations no other systemic toxic effects were detected except premature deaths and tubular degeneration/necrosis in the kidneys which were evident after gavage administration of dosages >150 mg/kg bw/d in a rat 3-month study. Effects were attributed to the high peak concentrations and did not occur in drinking water studies at similar or higher doses. Some studies with repeated application revealed minimal changes of single red blood cell parameters, however no clear hematotoxic effect was found. Changes in clinical chemistry parameters, observed in drinking water studies, were assumed to be associated with reduced consumption of water and/or food.”

 

No human information is available for this endpoint. However, there is no reason to believe that these results 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 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 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.

 

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 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 as well as the source substance Amphoacetates C8-C18 contain 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 Amphopropionates C12-18 contains propionate functions, whereas thesource 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 Amphopropionates C12-18 as well as the source 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 are available, demonstrating that this difference in composition is of no toxicological relevance.

 

Comparison of repeated dose toxicity data

	Target substance	Source substance	Source substance
	Amphopropionates C12-18	Amphopropionate C8	Amphoacetates C8-C18
Repeated dose toxicity	No data, read-across	key_RA_Repeated dose toxicity_64265-45-8_8.6.1_Evonik_2008_OECD407   OECD TG 407, rat (Wistar), oral: gavage   28 d NOAEL = 1000 mg a.i./kg bw/d; no toxicologically significant changes   1 (reliable without restriction), GLP	sup_RA_Repeated dose toxicity: oral: 931-291-0_8.6.1_Cognis_1990_OECD407   OECD TG 407, rat (Sprague-Dawley), oral: gavage   28 d NOAEL = 92.5 mg a.i./kg bw/d; increased liver weights (females)   2 (reliable with restrictions), no GLP
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_RA_Acute toxicity: oral: 931-291-0_8.5.1._Huntsman_1977_OECD401   similar to OECD TG 401, rat (Sprague-Dawley), oral: gavage   LD50 = 44.5 mL/kg (aqueous solution)   2 (reliable with restrictions), pre-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		sup_RA_Acute toxicity: oral: 931-291-0_8.5.1._Huntsman_1977b_OECD401   similar to OECD TG 401, rat (Sprague-Dawley), oral: gavage   LD50 = 34 mL/kg (aqueous solution)   2 (reliable with restrictions), pre-GLP

 

No experimental data on repeated dose toxicity are available for the target substance Amphopropionate C12 -18. However, reliable and relevant data are available with the closely related source substances Amphopropionate C8 and Amphoacetates C8-18.

No toxicologically significant changes were noted in any of the parameters examined/determined in the 28 d repeated dose toxicity study with Amphopropionate C8 (i.e. clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination. The NOAEL for Amphopropionate C8 was established at of 1000 mg/kg bw/day.

 

The 28 d NOAEL of Amphoacetates C8-18 based on an increase in liver weights was 250 mg/kg bw/day (aqueous solution at 37%), corresponding to 92.5 mg a.i./kg bw/day.

However, as only females showed an increase in liver weights and, moreover, no such changes were observed in the 28 d study with the source substance Amphopropionate C8, the overall NOAEL for the target substance Amphopropionates C12-18 based on weight-of-evidence is set at 1000 mg/kg bw/d.

 

This read-across is further supported by similarly low acute toxicity: all three substances have a low acute toxicity via the oral route as demonstrated by LD50 > 2000 mg a.i./kg bw.

 

Supporting data are available for acrylic acid: Following oral, dermal or inhalation administrations no other systemic toxic effects were detected except premature deaths and tubular degeneration/necrosis in the kidneys which were evident after gavage administration of dosages >150 mg/kg bw/d in a rat 3-month study. Effects were attributed to the high peak concentrations and did not occur in drinking water studies at similar or higher doses. Some studies with repeated application revealed minimal changes of single red blood cell parameters, however no clear hematotoxic effect was found. Changes in clinical chemistry parameters, observed in drinking water studies, were assumed to be associated with reduced consumption of water and/or food.

The slight effects observed with acrylic acid are not considered to be toxicologically relevant at the max. level of 1% of acrylic acid in the target substance.

 

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 Guideline 407 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 based on the similarly low acute toxicity via the oral route.

Thus, the results obtained with the source substance Amphopropionate C8 in the sub-acute 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

 

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

 

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 for specific target organ toxicity after repeated exposure according to Regulation (EC) No 1272/2008.