Hexanoic acid, 3,5,5-trimethyl-, 2,2,6,6-tetramethyl-1-[2-[(3,5,5-trimethyl-1-oxohexyl)oxy]ethyl]-4-piperidinyl ester

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

Reproductive toxicity of the test item was determined in the course of a Combined Repeated Dose Toxicity study with the Reproduction/Developmental Toxicity Screening study (OECD 422, GLP). The NOAEL for reproductive performance and fertility was set to 150 mg/kg bw/d in male and female Wistar rats. The NOAEL for developmental toxicity was 150 mg/kg bw/d.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and ServiceGmbH, Sulzfeld, Germany
- Age at study initiation: 11-13 weeks
- Fasting period before study: no
- Housing: individually, following exceptions: During overnight matings, male and female mating partners were housed together. Pregnant animals and their litters were housed together until PND 4 (end of lactation).
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 7d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): daily
- Mixing appropriate amounts with (Type of food): corn oil
- Storage temperature of food: RT

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: maximum 2 weeks
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged (how): pregnant animals and litter together

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- according GLP
- stability of the test substance in corn oil for a period of 7 days at room temperature was proven before the start of the study
- method stability of test item in drinking water: UV/VIS spectroscopy

Duration of treatment / exposure:

The duration of treatment covered a 2-week premating and a mating period in both sexes, approximately 1 week post-mating in males,
and the entire gestation period as well as 4 days of lactation and 2 weeks thereafter in females.

Frequency of treatment:

daily

Details on study schedule:

- Age at mating of the mated animals in the study: 13-14 weeks

Remarks:

Doses / Concentrations:
15, 50, 150 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: range finder test 300 and 1000 mg/kg bw, histopathological findings at 300 and 1000 mg/kg bw
- Rationale for animal assignment (if not random): Randomization

Positive control:

no

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: before the start of the administration period in order to randomize the animals. During the administration period body weight was determined on study day 0 (start of the administration period) and thereafter once a week at the same time of the day (in the morning).

FOOD CONSUMPTION
- weekly
- Food consumption was not determined during the mating period (male and female F0 animals).
- Food consumption of the F0 females with evidence of sperm was determined on GD 0, 7, 14 and 20.
- Food consumption of F0 females, which gave birth to a litter, was determined for PND 4

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: in the course of FOB
- Dose groups that were examined: all

HAEMATOLOGY: Yes
- Time schedule for collection of blood: end of administration period
- Anaesthetic used for blood collection: Yes, anaesthetized using isoflurane (Isoba®, Essex GmbH, Munich, Germany)
- Animals fasted: Yes
- How many animals: 5/sex/dose

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: end of administration period
- Animals fasted: Yes
- How many animals: 5/sex/dose

URINALYSIS: Yes
- Time schedule for collection of urine: males: after mating, females: 1 day before end of administration period
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: male: postnatal day 0, female: 10d after gestation
- Dose groups that were examined: all
- Battery of functions tested: sensory activity / grip strength / motor activity

Sperm parameters (parental animals):

stages of spermatogenesis were examined in histopathology

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: no

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality up to day 4, presence of gross anomalies

GROSS EXAMINATION OF DEAD PUPS:
yes, all stillborn pups and those pups, which died ahead of schedule, were examined externally, eviscerated and their organs were assessed macroscopically

Postmortem examinations (parental animals):

GROSS PATHOLOGY: Yes
1. Adrenal glands
2. All gross lesions
3. Aorta
4. Bone marrow (femur)
5. Brain
6. Cecum
7. Cervix
8. Coagulating glands
9. Colon
10. Duodenum
11. Eyes with optic nerve
12. Esophagus
13. Extraorbital lacrimal gland
14. Epididymides (modified Davidson’s solution)
15. Femur with knee joint
16. Heart
17. Ileum
18. Jejunum (with Peyer’s patches)
19. Kidneys
20. Larynx
21. Liver
22. Lungs
23. Lymph nodes (axillary and mesenteric)
24. Mammary gland (male and female)
25. Nose (nasal cavity)
26. Ovaries (modified Davidson’s solution)
27. Oviducts
28. Pancreas
29. Parathyroid glands
30. Pharynx
31. Pituitary gland
32. Prostate gland
33. Rectum
34. Salivary glands (mandibular and sublingual)
35. Sciatic nerve
36. Seminal vesicles
37. Skeletal muscle
38. Spinal cord (cervical, thoracic and lumbar cord)
39. Spleen
40. Sternum with marrow
41. Stomach (forestomach and glandular stomach)
42. Target organs
43. Testes (modified Davidson’s solution)
44. Thymus
45. Thyroid glands
46. Trachea
47. Urinary bladder
48. Uterus
49. Vagina

HISTOPATHOLOGY
ORGAN WEIGHTS: Adrenal glands, Brain, Heart, Kidneys, Liver, Spleen, Thymus

HISTOPATHOLOGY: Yes, control and high dose group, gross lesions in all animals
1. All gross lesions
2. Adrenal glands
3. Bone marrow (femur)
4. Brain
5. Cecum
6. Cervix
7. Coagulating glands
8. Colon
9. Duodenum
10. Epididymides
11. Heart
12. Ileum
13. Jejunum
14. Kidneys
15. Liver
16. Lung
17. Lymph nodes (mesenteric and axillary lymph nodes)
18. Ovaries
19. Oviducts
20. Peyer’s patches
21. Prostate
22. Rectum
23. Sciatic nerve
24. Seminal vesicles
25. Spinal cord (cervical, thoracic and lumbar cords)
26. Spleen
27. Stomach (forestomach and glandular stomach)
28. Testes
29. Thymus
30. Thyroid glands
31. Trachea
32. Urinary bladder
33. Uterus
34. Vagina

Postmortem examinations (offspring):

SACRIFICE
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows: All pups delivered from the F0 parents were examined as soon as possible on the day of birth

GROSS NECROPSY
All surviving pups (sacrificed on PND 4 under isoflurane anesthesia with CO2), all stillborn pups and those pups, which died ahead of schedule, were examined externally, eviscerated and their organs were assessed macroscopically.

Statistics:

Blood parameters:
For parameters with bidirectional changes:
Non-parametric one-way analysis using KRUSKAL-WALLIS test. If the resulting p-value was equal or less than 0.05, a pairwise comparison of each dose
group with the control group was performed using WILCOXON-test (twosided) for the hypothesis of equal medians
For parameters with unidirectional changes:
Pairwise comparison of each dose group with the control group using the WILCOXON-test (one-sided) for the hypothesis of equal medians

Urinalysis parameters: WILCOXON-test (one-sided)

Food consumption: DUNNETT-test (twosided)

fertility indices: FISHER'S EXACT test

Proportions of affected pups per litter with necropsy observations: WILCOXON-test

Weight parameters: KRUSKAL-WALLIS test

Reproductive indices:

Male reproduction data:
- Male mating index
- Male fertility index

Female reproduction and delivery data:
- Female mating index
- Female fertility index
- Gestation index
- Live birth index
- Post implantation loss

Offspring viability indices:

Pup number and status at delivery
Pup viability/mortality
Sex ratio
Pup body weight data

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Other effects:

no effects observed

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Fertility indices for male and female animals were not impaired by the test-substance administration. In addition, live birth indices of pups in all test groups were not influenced. The viability index as indicator for pup mortality was not altered dose-dependently. The test substance did not influence fertility.

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed up to the highest dose

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings:

not examined

Live birth indices of pups in all test groups were not influenced. The viability index as indicator for pup mortality was not altered dose-dependently. The test substance did not influence fertility.

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed up to the highest dose level

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

150 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Procedure and observations

The test item was administered orally by gavage to groups of 10 male and 10 female Wistar rats (F0 animals) at dose levels of 0 mg/kg body weight/day (corn oil served as vehicle), 15 mg/kg bw/d, 50 mg/kg bw/d and 150 mg/kg bw/d. The duration of treatment covered a 2-week premating and a mating period in both sexes, approximately 1 week post-mating in males, and the entire gestation period as well as 4 days of lactation and 2 weeks thereafter in females. A detailed clinical observation was performed in all animals. Body weights and food consumption were determined in F0 animals. Clinicochemical and hematological examinations as well as urinalyses and FOB were performed in all animals towards the end of the administration period. All animals were assessed by gross pathology; weights of selected organs were recorded and a histopathological examination was performed. The pups were sexed and examined for macroscopically evident changes on PND 0. They were weighed on PND 1 and on PND 4. Their viability was recorded. At necropsy on PND 4, all pups were sacrificed with CO2 and examined macroscopically for external and visceral findings.

Fertility indices for male and female animals were not impaired by the test-substance administration. In addition, live birth indices of pups in all test groups were not influenced. The viability index as indicator for pup mortality was not altered dose-dependently. The test substance did not influence fertility.

Discussion

Under the conditions of this Combined Repeated Dose Toxicity Study with the Reproduction/ Developmental Toxicity Screening Test (OECD 422) the oral administration by gavage of the test item to male and female Wistar rats revealed no signs of systemic toxicity up to a dose level of 150 mg/kg bw/d in animals of both sexes. Thus, the no observed adverse effect level (NOAEL) for general systemic toxicity was 150 mg/kg bw/d in male and female animals. The NOAEL for reproductive performance and fertility was set to 150 mg/kg bw/d in male and female Wistar rats. The NOAEL for developmental toxicity was 150 mg/kg bw/d.

Short description of key information:
Reproductive toxicity of the test item was determined in the course of a Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening study (OECD 422, GLP). The NOAEL for reproductive performance and fertility was set to 150 mg/kg bw/d in male and female Wistar rats. The NOAEL for developmental toxicity was 150 mg/kg bw/d.

Effects on developmental toxicity

Description of key information

Reproductive toxicity of the test item was determined in the course of a Combined Repeated Dose Toxicity study with the Reproduction/Developmental Toxicity Screening study (OECD 422, GLP). The NOAEL for reproductive performance and fertility was set to 150 mg/kg bw/d in male and female Wistar rats. The NOAEL for developmental toxicity was 150 mg/kg bw/d.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

150 mg/kg bw/day

Study duration:

subacute

Species:

rat

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

Procedure and observations

The test item was administered orally by gavage to groups of 10 male and 10 female Wistar rats (F0 animals) at dose levels of 0 mg/kg body weight/day (corn oil served as vehicle), 15 mg/kg bw/d, 50 mg/kg bw/d and 150 mg/kg bw/d. The duration of treatment covered a 2-week premating and a mating period in both sexes, approximately 1 week post-mating in males, and the entire gestation period as well as 4 days of lactation and 2 weeks thereafter in females. A detailed clinical observation was performed in all animals. Body weights and food consumption were determined in F0 animals. Clinicochemical and hematological examinations as well as urinalyses and FOB were performed in all animals towards the end of the administration period. All animals were assessed by gross pathology; weights of selected organs were recorded and a histopathological examination was performed. The pups were sexed and examined for macroscopically evident changes on PND 0. They were weighed on PND 1 and on PND 4. Their viability was recorded. At necropsy on PND 4, all pups were sacrificed with CO2 and examined macroscopically for external and visceral findings.

Fertility indices for male and female animals were not impaired by the test-substance administration. In addition, live birth indices of pups in all test groups were not influenced. The viability index as indicator for pup mortality was not altered dose-dependently. The test substance did not influence fertility.

Discussion

Under the conditions of this Combined Repeated Dose Toxicity Study with the Reproduction/ Developmental Toxicity Screening Test (OECD 422) the oral administration by gavage of the test item to male and female Wistar rats revealed no signs of systemic toxicity up to a dose level of 150 mg/kg bw/d in animals of both sexes. Thus, the no observed adverse effect level (NOAEL) for general systemic toxicity was 150 mg/kg bw/d in male and female animals. The NOAEL for reproductive performance and fertility was set to 150 mg/kg bw/d in male and female Wistar rats. The NOAEL for developmental toxicity was 150 mg/kg bw/d.

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for reproductive toxicity under Regulation (EC) No. 1272/2008.