11-aminoundecanoic acid

Endpoint summary

Description of key information

Repeated Dose 28-day oral rat toxicity study (OECD TG 407):
- Rat (female/male): NOAEL = 5000 ppm  (= 472 mg/kg bw for males and 507 mg/kg bw  for females)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

August 2000-October 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EPA Guideline 799, 9620-62-158

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River UK, Margate, UK
- Age at study initiation: 6 weeks
- Weight at study initiation: 146-260 g
- Fasting period before study: No
- Housing: 2 rats of same sex and group in suspended wire-mesh cages (43x21.5x18 cm)
- Diet : ad libitum
- Water : ad libitum
- Acclimation period: 9 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 +/- 2
- Humidity (%): 50 +/- 20
- Air changes (per hr): 12 cycles
- Photoperiod (hrs dark / hrs light): 12/12 (7.00am-7.00pm)


IN-LIFE DATES: From: 22 August 2000 To: 29 September 2000

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): weekly
- Mixing appropriate amounts with (Type of food): Powder maintenance diet UAR A04C P 2.5
- Storage temperature of food: At room temperature

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Homogeneity and stability of the dietary admixtures were checked in a previous rat study in the same test facility (CIT 20436 RSR - see section 7.8.2) at 2000 ppm and 30000 ppm. Homogeneity and stability were also checked at 1250 ppm in the present study.
Stability was checked on samples taken from dietary admixtures after 0 and 10 days of storage in closed bags and 0, 5 and 9 days of storage in open feeder.
Concentrations were determined for a sample taken from each dietary admixture including controls in weeks 1 and 4.
The analytical data indicated that the variance between nominal and actual dosage was acceptable.
The concentrations of 1250, 5000 or 20000 ppm corresponded to achieved dosages of 118, 472 or 1644 mg/kg/day for the males and 129, 507 or 1828 mg/kg/day for the females.

Duration of treatment / exposure:

28 days

Frequency of treatment:

Dietary exposure at constant concentrations

Remarks:

Doses / Concentrations:
1250, 5000 and 20000 ppm
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
118, 472 and 1644 mg/kg/day
Basis:
other: Based on analytical verification

No. of animals per sex per dose:

6

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: No data
- Post-exposure recovery period in satellite groups: Not applicable

Positive control:

Not included

Observations and examinations performed and frequency:

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


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once weekly


BODY WEIGHT: Yes
- Time schedule for examinations: once weekly


FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes


FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: day 28
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes
- How many animals: 5 per sex and per dose
- Standard toxicity study parameters were examined.


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day 28
- Animals fasted: Yes
- How many animals: 5 per sex and per dose
- Standard toxicity study parameters were examined.


URINALYSIS: Yes
- Time schedule for collection of urine: day 28
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Standard toxicity study parameters were examined.


NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: end of week 4
- Dose groups that were examined: all (5 rats per sex)
- Battery of functions tested: sensory activity / grip strength / motor activity / other: vision, audition, reflexes


OTHER: rectal temperature at the end of week 4

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
A complete macroscopic post-mortem examination was performed on all study animals, including examination of external surfaces, all orifices, cranial cavity, external surface of bain and spinal cord, thoracic, abdominal and pelvic cavities with the associated organs and tissues, and neck with the associated organs and tissues.

HISTOPATHOLOGY: Yes
Microscopic examination was performed for the first 5 animals on :
- all the following tissues for control and high-dose groups: macroscopic lesions, adrenals, brain, cecum, colon, duodenum, epididymides, esophagus, heart, ileum, jejunum, kidneys, liver, lungs with bronchi, lymph nodes, ovaries, sciatic nerve, seminal vesicles, spinal cord, spleen, stomach with forestomach, testes, thymus, thyroids with parathyroids, trachea, urinary bladder, uterus, vagina,
- kidneys for low- and intermediate-dose groups,
- sternum with bone marrow for males of control and high-dose groups.

Other examinations:

Not included

Statistics:

Statistical analysis was perfomed on bodyweight, food consumption, hematology, blood chemistry, urinalysis and organ weight data, using a statistical decision tree to select the most appropriate test for each parameter.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

BODY WEIGHT AND WEIGHT GAIN
At 5000 ppm, a slight and transitory decrease (not statistically significant) in body weight gain in males during weeks 2 and 3 was noted and was not considered as an adverse effect.
At 20000 ppm, a decrease in body weight gain in both males and females was noted during weeks 1, 2 and 3.
These dose-related decreases in body weight gain correlated with lower food consumption values.

HAEMATOLOGY
At 20000 ppm, decrease in hemoglobin concentration, packed cell volume, mean cell volume and mean cell hemoglobin, decrease in Activated Partial Thromboplasmin (APTT) and increase in fibrinogen level were noted in males.
Treated females at 20000 ppm showed also a tendency to lower hemoglobin concentration, lower packed cell volume, decreased APTT values and increased fibrinogen level.
These differences in red blood cell or coagulation parameters observed in the 20000 ppm group were considered to be related to treatment with the test substance.

CLINICAL CHEMISTRY
At 20000 ppm, a decrease in inorganic phosphorus levels, an increase in urea and triglyceride levels and a decrease in alkaline phosphatase or alanine aminotransferase activities were noted in treated males.
Increased urea levels were noted among treated females at 20000 ppm.
The above-mentioned differences noted in the 20000 ppm group were considered to be the consequence of treatment with the test substance.

ORGAN WEIGHTS
At 5000 or 20000 ppm, the absolute and relative kidney weights were higher when compared to controls, as follows:

Concentration (ppm) 5000 20000
-----------------------------------------------------
Males +15 (+21) +23 (+41**)
Females +10 (+7) +52** (+64**)
-----------------------------------------------------
relative weight in brackets; **: p<0.01

At 20000 ppm, these differences correlated with macroscopic and microscopic findings in the kidneys and were attributed to treatment with the test substance.

GROSS PATHOLOGY
At 5000 ppm, grey/green color of the kidneys was observed in 1/6 males.
At 20000 ppm, grey/green color of the kidneys was observed in 3/6 males (associated with enlargement or irregular color in one male); greyish/whitish or yellowish areas were noted in 5/6 females.
These abnormalities observed among the 5000 or 20000 ppm groups correlated with higher kidney weights and were considered to be treatment-related.

HISTOPATHOLOGY: NON-NEOPLASTIC
At 20000 ppm, lesions of the renal papilla were seen in 5/5 females (e.g. acute inflammatory cells infiltration, hyperplasia of the epithelium, dilatation of collecting ducts) and both sexes showed cortical tubular dilatation.

Key result

Dose descriptor:

NOAEL

Effect level:

5 000 ppm

Based on:

test mat.

Remarks:

equivalent to 472 and 507 mg/kg/day for males and females, respectively

Sex:

male/female

Basis for effect level:

other:

Remarks on result:

other: see basis for effect level

Critical effects observed:

not specified

Conclusions:

The dose level of 5000 ppm of 11-aminoundecanoic acid (corresponding to 472 mg/kg/day for the males and 507 mg/kg/day for the females) was established as a NOAEL in this 28-day study in rats by dietary administration.
At this dose-level, there was only a slight decrease in body weight gain (not statistically significant), correlating with lower food consumption in males.

Executive summary:

In a repeated-dose toxicity study (G. Chevalier, CIT, 2001) complying with OECD Guideline 407 (Repeated Dose 28-day Oral Toxicity Study in

Rodents), Sprague-Dawley rats (6 per dose and per sex) received plain diet (controls) or 11-AMINOUNDECANOIC ACID (batch No.

USA000523365) mixed in the diet at constant concentrations of 1250, 5000 or 20000 ppm for 4 weeks.

Examinations and measurements included mortality, clinical signs, functional observation battery (for potential signs of neurotoxicity), bodyweight,

food consumption, hematology, blood biochemistry, urinalysis, gross examination at necropsy, and histopathology.

Based on analytical verifications, the achieved dosages were 118, 472 and 1644 mg/kg/day for the males and 129, 507and 1828 mg/kg/day for the

females, for the 1250, 5000 and 20000 ppm concentrations, respectively.

At 5000 ppm, a slight and transitory decrease in bodyweight gain was noted for males in weeks 2 and 3 was but was not considered significant. At

20000 ppm, decreased bodyweight gain was observed for both genders in weeks 1, 2 and 3, correlating with a lower food consumption.

Decreased hemoglobin concentration, packed cell volume, mean cell volume and mean cell hemoglobin, activated partial thromboplastin time and

increased fibrinogen level were obserevd in males given 20000 ppm. Females given 20000 ppm also showed a tendency to lower hemoglobin

concentration, packed cell volume, activated partial thromboplasmin and increased fibrinogen level. Decreased inorganic phosphorus plasma

concentrations, increased urea and triglyceride plasma concentrations, and decreased alkaline phosphatase and alanine aminotransferase

activities were also observed for males given 20000 ppm. Increased urea plasma concentrations were noted among females given 20000 ppm. All

these clinical chemistry changes at the high dose were attributed to 11-AMINOUNDECANOIC ACID.

At 5000 or 20000 ppm, the absolute and relative kidney weights were higher (up to +52% and +64%, respectively) than in controls. This correlated with 
grey/green color of the kidneys in some males given 5000 or 20000 ppm, and greyish/whitish or yellowish areas in most females given 20000 ppm. 
Microscopic examination showed lesions of the renal papilla (e.g. acute inflammatory cell infiltration, epithelium hyperplasia, dilatation of collecting
 ducts) in all females given 20000 ppm. Cortical tubular dilation was noted for both genders at the high dose. All these pathology changes were 
attributed to 11-AMINOUNDECANOIC ACID.Consequently, under the conditions of this study, 5000 ppm of 11 -AMINOUNDECANOIC ACID in diet 
(equivalent to 472 and 507 mg/kg/day for males and females, respectively) was established as a No Observed Adverse Effect Level (NOAEL) following 
4 weeks of administration.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

472 mg/kg bw/day

Study duration:

subacute

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

Five studies are reported for this endpoint: a repeated dose 28 -day oral toxicity test (rats), two repeated dose 90 -day oral toxicity tests (rats and mice) and two repeated dose 14 -day oral toxicity tests (rats and mice).

In the fourteen-day studies, subacute studies performed by the US-NTP, male and female rats and mice were administered 11 -aminoundecanoic acid for 2 weeks. Although these studies were well conducted, they were preliminary studies to subacute studies and did not therefore provide enough information for the hazard assessment in repeated dose toxicity. Indeed, only daily observation for mortality and gross necropsies on all animals at the end of the study were performed. Consequently, these studies were discarded in favour of the other studies reported in this endpoint.

The two 90 -day oral range-finding studies in rats and mice, preliminary to chronic/carcinogenicity studies, performed by the US National Toxicology Program were selected as supporting studies. These range-finding studies did not cover all the parameters recommended by the OECD guidelines (hematology, clinical biochemistry, urine analysis and functional observation battery were not performed and daily food intake, clinical signs, food consumption, and organ weights were not reported) and did not allow to establish a precise NOAEL in rats (LOAEL = 9000 ppm) but they provide information on the general toxicological effects arising from repeated exposures. These studies showed that the kidney was a target organ of 11 -aminoundecanoic acid. Indeed, multifocal tubular or focal mineralization, transitional-cell hyperplasia and hyperplasias of the renal pelvis were observed in the kidney either in rats or in mice started at the 9000 ppm and 15000 ppm dose-levels, respectively.

In a subacute oral toxicity study (28 -day), 11 -aminoundecanoic acid was given by dietary admixture to rats (6 per sex) for 4 weeks at the concentrations of 1250, 5000 and 20000 ppm. This study performed according to OECD Test Guideline 407 and following the GLP has been chosen as key study. At 5000 ppm, the only adverse effect was a slight decrease in body weight gain (not statistically significant) correlating with lower food consumption noted among treated males. At 20000 ppm, moderate decrease in body weight gain and food consumption were noted among treated males and females. At clinical pathology, lower values for red blood cell parameters, and APTT, higher fibrinogen, and urea levels in both sexes were noted. Decreased liver enzyme activities and increased triglyceride levels were noted in males. Treatment-related lesions were also observed in the kidneys (lesions of the renal papilla, acute inflammatory cells infiltration, hyperplasia of the epithelium, dilatation of collecting ducts in females) and both sexes showed tubula dilatation. Consequently, a No Observed Adverse Effect Level (NOAEL) of 5000 ppm (472 mg/kg/day for males and 507 mg/kg /day for females) was identified.

Repeated dose toxicity: via oral route - systemic effects (target organ) urogenital: kidneys

Justification for classification or non-classification

There are conclusive but not sufficient data for the classification of 11 -aminoundecanoic acid with regard to repeated toxicity. No classification for repeated toxicity has to be applied for 11 -aminoundecanoic acid according to EU Directive 67/584/EEC and EU regulation (EC) No 1272/2008 (CLP).