Registration Dossier

Administrative data

Endpoint:
screening for reproductive / developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012/2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Preliminary Reproduction Toxicity Screening Test (Precursor Protocol of GL 421)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Description: White solid
Storage Conditions: Room temperature (20 ± 5 °C); avoiding strong oxidizing agents, strong acids, and strong bases

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories, B.V. Kreuzelweg 53 5961 NM Horst / Netherlands
- Age at study initiation: 11 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: 8d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
polyethylene glycol
Remarks:
PEG 400 / 0.5% Tween 80
Details on exposure:
DIET PREPARATION
- Rate of preparation of diet (frequency): weekly
- Mixing appropriate amounts with (Type of food): PEG 400 / 0.5% Tween 80
- Storage temperature of food: RT

- applied as a suspension

- Dose formulations were stored in the refrigerator (5 ± 3 °C) in glass beakers
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
- method stability of test item in vehicle: gas chromatography
- formulations investigated during the study were found to comprise test item in the range of 81.4% to 112.7% and, thus, the required content limit of ±20% with reference to the nominal content was met.
Duration of treatment / exposure:
Males were treated over a 14-day pre-pairing period and during the pairing period up to one day before necropsy. Females were treated throughout the pre-pairing, pairing, gestation and lactation period up to the day 3 post partum.
Frequency of treatment:
daily
Details on study schedule:
- Age at mating of the mated animals in the study: 12-13 weeks

Doses / concentrationsopen allclose all
Dose / conc.:
100 mg/kg bw/day (actual dose received)
Dose / conc.:
300 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:
10
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: 28d study
- Rationale for animal assignment (if not random): Randomization
Positive control:
no

Examinations

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

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
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

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
no effects observed
Description (incidence and severity):
No test item-related clinical signs were noted in males and females at any dose level.
One male treated at 100 mg/kg bw/day showed a slight reddish secretion from the nose during the last two days of the after pairing period. In this time this male lost also 5 % of his body weight. No macroscopical abnormalities were found for this male. Due to the isolated occurrence, this finding was considered to be incidental.
Two females treated at 300 and one female treated at 1000 mg/kg bw/day showed slight hair loss on the left thigh or in the neck.
Mortality:
mortality observed, non-treatment-related
Description (incidence):
There were no test item-related deaths.
One female treated at 100 mg/kg bw/day died during the pre-pairing period as a consequence of an intubation error. One female treated at 1000 mg/kg bw/day was removed from the study due to a closed vagina.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
In males treated at 1000 mg/kg bw/day, a slight reduction in mean body weight gain was observed during the pre-pairing period. However, this slight and transient reduction was considered not to be adverse.
There were no test item-related effects on mean body weights and mean body weight gain at 100 and 300 mg/kg bw/day.
The overall values of mean body weight gain at the dose levels of 0, 100, 300 and 1000 mg/kg bw/day were: + 12 %, + 11 %, + 11 % and + 9 % during the pre-pairing period, + 2 %, + 3 %, + 2 % and + 3 % during the pairing period and + 2 %, + 2 %, + 2 % and + 2 % during the after pairing period (percentages refer to the body weight gain within the period).

In female animals, there were no effects on mean body weights and mean body weight gains at any dose level and any study phase.
The slight reduction in mean body weight gain in females treated at 1000 mg/kg bw/day observed during the gestation period was most probably based on the slightly lower mean number of fetuses and not a test item-related effect.
The overall values of mean body weight gain at the dose levels of 0, 100, 300 and 1000 mg/kg bw/day were: + 10 %, + 8 %, + 10 % and + 8 % during the pre-pairing period, + 63 %, + 63 %, + 61 % and + 56 % during the gestation period and + 5 %, + 5 %, + 7 % and + 6 % during the lactation period (percentages refer to the body weight gain within the period).
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
There were no effects on mean food consumption at any dose level and in any study phase.
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
The histopathological evaluation of the reproductive organs did not reveal any relevant changes in the high-dose animals.
Special emphasis on stages of spermatogenesis and histopathology of interstitial testicular cell structure did not reveal any differences between control (group 1) and high dose (group 4) males.
Sperm staging: the stages were checked on completeness of cell populations, completeness of stages, and potential degenerative changes. An assessment of the stages of spermatogenesis in the unilaterally occurring minimal and focal degenerative tubules with atrophy in a few group 1 and 4 males was not possible.
All tubular changes in testes of male groups 1 to 4 were considered to be within the normal biological range.
All findings in testes and epididymides were considered to be incidental and unrelated to the test item. The prostate and seminal vesicles did also not reveal any test item-related morphological changes.
The remaining microscopical findings recorded in this study were to be within the range of normal background lesions which may be recorded in animals of this strain and age.
Other effects:
no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed
Description (incidence and severity):
No effects on mating performance or fertility was observed at any dose level.
Mating of all females was recorded during the first pairing period. The precoital time was not affected by the treatment with th test item. Mean (median) precoital times calculated for the pairing period were 2.9 (3), 2.8 (3), 2.4 (2) and 2.2 (2) days in order of ascending dose levels. In one female at 1000 mg/kg bw/day a closed vagina was noted when the first vaginal smear was scheduled on day one of the pairing period. This female was removed from the study one day later.
All mated females in the study were pregnant. As a result, fertility indices (number of females achieving pregnancy as a percentage of females paired) and conception rates (number of females achieving pregnancy as a precentage of females mated) were 100 % in the control group and at all dose levels.
No birth was recorded for one female at the dose level of 1000 mg/kg bw/day. At termination on day 25 post coitum, only one fetal resorption was found in this female. Therefore, gestation index (number of females with living pups as a percentage of females pregnant) was 100 % in the control group and at the dose levels of 100 and 300 mg/kg bw/day and 90 % at the dose level of 1000 mg/kg bw/day.

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (actual dose received)
Sex:
male/female
Basis for effect level:
other: absence of adverse effects

Target system / organ toxicity (P0)

Critical effects observed:
no

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
No effects on pup body weights were noted at any dose level.
In animal no. 46, 54 (group 1), 63 (group 2) and 88 (group 4) all pups were incorrectly weighed on day 1 post partum due to a technical error. Due to the low incidence, the exclusion of these litters on this day has no impact on the study.
Mean body weights of pups on day 1 post partum were: 6.1 g, 6.8 g, 6.5 g and 6.5 g, at the dose levels of 0, 100, 300 and 1000 mg/kg bw/day respectively, body weight gain of pups during the first four days of the lactation period was + 49.4 %, + 46.1 %, + 48.9 % and + 48.8 %, respectively.
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Description (incidence and severity):
No macroscopical abnormalities were noted in any pup at any dose level.
Histopathological findings:
not examined

Effect levels (F1)

Dose descriptor:
NOAEL
Generation:
F1
Effect level:
1 000 mg/kg bw/day (actual dose received)
Sex:
male/female
Basis for effect level:
other: absence of adverse effects

Target system / organ toxicity (F1)

Critical effects observed:
no

Overall reproductive toxicity

Reproductive effects observed:
not specified

Any other information on results incl. tables

Table 2: P Animals Breeding for F1 Litters

Group (mg/kg bw/day)

1 (0)

2 (100)

3 (300)

4 (1000)

Female numbers

45 – 55

56 – 66

67 – 77

78 – 88

Number of females paired (A)

11

10

11

10

Number of females mated

11

10

11

10

Number of pregnant females

11

10

11

10

Numbers of females, which did not deliver any pups (B)

0

0

0

1

Number of females which reared their pups until day 4 post partum

11

10

11

9

(A)   Female no. 64 died on day 13 of the pre-mating period. Female no. 78 was removed from the study due to a closed vagina.

(B)   Female no. 86 had only one fetal resorption.

Applicant's summary and conclusion

Conclusions:
Based on these results, the NOAEL (No Observed Adverse Effect Level) for general and reproductive toxicity in males and females was considered to be 1000 mg/kg bw/day, the highest dose level tested.
Executive summary:

The purpose of this study was to generate preliminary information concerning the effects of the test substance on male and female reproductive performance such as gonadal function, mating behavior, conception and parturition.

Four groups of 11 males and 11 females were treated by gavage with the test substance once daily. Males were treated over a 14 -day pre-pairing period and during the pairing period up to one day before necropsy. Females were treated throughout the pre-pairing, pairing, gestation and lactation period up to the day 3 post partum.

The following dose levels were used:

- Group 1: 0 mg/kg bw/day (control group)

- Group 2: 100 mg/kg bw/day

- Group 3: 300 mg/kg bw/day

- Group 4: 1000 mg/kg bw/day

A standard dose volume of 4 mL/kg body weight with a daily adjustment to the actual body weight was used. Control animals were dosed with the vehicle alone (PEG 400 / 0.5 % Tween 80).

The following results were obtained:

Parent Animals

- Mortality and General Tolerability: There were no test item-related deaths. One female treated at 100 mg/kg bw/day died as a consequence of an intubation error during the pre-pairing period. No test item-related clinical signs were noted in males and females at any dose level.

- Food Consumption: There were no effects on mean food consumption at any dose level and in any study phase.

- Body Weights: In males treated at 1000 mg/kg bw/day, a slight reduction in mean body weight gain was observed during the pre-pairing period. However, this slight and transient reduction was considered not to be adverse. Body weights and body weight gain in females were not affected by the treatment with the test item up to and including the dose level of 1000 mg/kg bw/day.

- Reproduction and Breeding Data: No effects on mating performance, fertility, corpora lutea count or duration of gestation were observed at any dose level.

- Organ Weights: No test item-related effects on organ weights were noted at any dose level.

- Macroscopical Findings and Histopathological Examinations: No findings related to the treatment with the test item were noted during macroscopical and histopathological examinations in males or females at any dose level.

Litter Data - F1 Pups

- Findings at First Litter Check and during Lactation: No test item-related findings were noted in pups at any dose-level. Pups sex ratio was not affected by the exposure to the test item at any dose level.

- Pup Weights to Day 4 Post Partum: No effects on pup body weights or body weight gain were noted at any dose level.

- Macroscopical Findings: No findings were noted in pups at any dose level.

Based on the results, the NOAEL (No Observed Adverse Effect Level) for general and reproductive toxicity in males and females was considered to be 1000 mg/kg bw/day, the highest dose level tested.