N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 May 2012 - 27 July 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: The United States Environmental Protection Agency (EPA) Health Effects Test Guidelines, OPPTS 870.3650, Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test, July 2000.

GLP compliance:

yes (incl. QA statement)

Remarks:

WIL Research Europe B.V., Hambakenwetering 7, 5231 DD 's-Hertogenbosch, The Netherlands

Test material

Test material information

Constituent 1

Reference substance name:

N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine

EC Number:

257-406-8

EC Name:

N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine

Cas Number:

51772-35-1

Molecular formula:

C24H29N

IUPAC Name:

N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine

Details on test material:

- Physical state: solid/white
- Analytical purity: 99.0 g/100 g determined by 1H-MR spectroscopy
- Expiration date of the lot/batch: July 15, 2015
- Storage condition of test material: Room temperature; avoid temperatures > 35°C

Test animals

Species:

rat

Strain:

other: Crl:WI(Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: 11 weeks
- Weight at study initiation: about 200 g (fermales) and 300 g( males)
- Housing:
Pre-mating: Animals were housed in groups of 5 animals/sex/cage in Macrolon plastic cages (MIV type, height 18 cm).
Mating: Females were caged together with males on a one-to-one-basis in Macrolon plastic cages (MIII type, height 18 cm).
Post-mating: Males were housed in their home cage (Macrolon plastic cages, MIV type, height 18 cm) with a maximum of 5 animals/cage. Females wwere individually housed in Macrolon plastic cages (MIII type, height 18 cm).
Lactation: Pups were kept with the dam until termination in Macrolon plastic cages (MIII type, height 18 cm). During locomotor activity monitoring of the dams the pups were kept warm in their home cage using bottles filled with warm water. In order to avoid hypothermia of pups, pups were not left without their dam or a bottle filled with warm water for longer than 30-40 minutes.
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water: ad libitum, tap water
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 24°C
- Humidity (%): 40 - 70 %
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

propylene glycol

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Formulations (w/w) were prepared daily within 6 hours prior to dosing and were homogenized to a visually acceptable level. Adjustment was made for specific gravity of the vehicle. No correction was made for the purity of the test substance.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Based on trial formulations performed at WIL Research Europe.
- Amount of vehicle (if gavage): 5 ml/kg

Details on mating procedure:

Following a minimum of 14 days of exposure for the males and females, one female was cohabitated with one male of the same treatment group, avoiding sibling mating. Detection of mating was confirmed by evidence of sperm in the vaginal lavage or by the appearance of an intravaginal copulatory plug. This day was designated Day 0 post-coitum. Once mating occurred, the males and females were separated. A maximum of 14 days was allowed for mating, after which females who had not shown evidence of mating were separated from their males. Detection of mating was not confirmed for animal nos. 50, 63 and 76 which did deliver live offspring. The mating date for these animals was estimated at 21 days prior to the actual delivery date. This day was designated Day 0 postcoitum

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were conducted on a single occasion during the treatment phase (05 June 2012), according to a validated method (Project 499646, BASF Project 05Y0630/11X472). Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations). Stability in vehicle over 6 hours at room temperature was also determined (highest and lowest concentration).
The accuracy of preparation was considered acceptable if the mean measured concentrations were 85-115% of the target concentration. Homogeneity was demonstrated if the coefficient of variation was ≤ 10%. Formulations were considered stable if the relative difference before and after storage was maximally 10%.

Duration of treatment / exposure:

Males were exposed for 29 days, i.e. 2 weeks prior to mating, during mating, and up to the day prior to scheduled necropsy. Females were exposed for 40-54 days, i.e. during 2 weeks prior to mating, during mating, during post-coitum, and during at least 4 days of lactation (up to the day prior to scheduled necropsy). Female nos. 49 and 50 (Group 1), 53 (Group 2), 65 and 66 (Group 3) were not dosed during littering.

Frequency of treatment:

Once daily for 7 days per week, approximately the same time each day with a maximum of 6 hours difference between the earliest and latest dose. Animals were dosed up to the day prior to scheduled necropsy.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

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: Dose levels were based on results of a 14-day dose range finding study.

Examinations

Parental animals: Observations and examinations:

At dose level allocation, 5 animals/sex/group were randomly selected for functional observations, locomotor activity, clinical pathology, organ weights (full list) and histopathology.

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily, detailed clinical observations were conducted for all animals after dosing at no specific time point, but within a similar time period after dosing for the respective animals. Once prior to start of treatment and at weekly intervals during the treatment period this was also performed
outside the home cage in a standard arena.

BODY WEIGHT: Yes
- Time schedule for examinations: Males and females were weighed on the first day of exposure and weekly thereafter. Mated females were weighed on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum and during lactation on Days 1 and 4.

FOOD CONSUMPTION:
Weekly, except for males and females which were housed together for mating and for females without evidence of mating. Food consumption of
mated females was measured on Days 0, 4, 7, 11, 14, 17 and 20 postcoitum and on Days 1 and 4 of lactation.

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

OPHTHALMOSCOPIC EXAMINATION: Yes / No / No data
- Time schedule for examinations:
- Dose groups that were examined:

HAEMATOLOGY: Yes
- Time schedule for collection of blood: on the day of scheduled post mortem examination between 7.00 and 10.30 a.m.
- Anaesthetic used for blood collection: Yes, isoflurane
- Animals fasted: Yes
- How many animals: the selected 5 animals/sex/group
- Parameters checked: White blood cells, Differential leucocyte count, Red blood cells, Reticulocytes, Red blood cell distribution width, Haemoglobin, Haematocrit, Mean corpuscular volume, Mean corpuscular haemoglobin, Mean corpuscular haemoglobin concentration MCHC, Platelets, Prothrombin time, Activated Partial thromboplastin time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: on the day of scheduled post mortem examination between 7.00 and 10.30 a.m.
- Animals fasted: Yes
- How many animals: the selected 5 animals/sex/group
- Parameters checked: Alanine aminotransferase, Aspartate aminotransferase, Alkaline phosphatase, Total Protein, Albumin, Total Bilirubin, Urea, Creatinine, Glucose, Cholesterol, Sodium, Potassium, Chloride, Calcium, Inorganic Phosphate, Bile acids

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: The selected males were tested during Week 4 of treatment and the selected females were tested towards the end of the scheduled lactation period after clinical signs observations (incl. arena observations, if applicable) and before blood sampling.
- Dose groups that were examined: the selected 5 animals/sex/group.
- Battery of functions tested: hearing ability, pupillary reflex, static righting reflex, grip strength, locomotor activity

REPRODUCTION DATA
Male number paired with, mating date, confirmation of pregnancy, and delivery day were recorded. Pregnant females were examined to detect signs of difficult or prolonged parturition, and cage debris of pregnant females was examined to detect signs of abortion or premature birth. Any deficiencies in maternal care (such as inadequate construction or cleaning of the nest, pups left scattered and cold, physical abuse of pups or apparently inadequate lactation or feeding) were examined (see section 7.8.1 and 7.8.2 for details).

Sperm parameters (parental animals):

From the selected 5 males of the control and high dose group, and all males suspected to be infertile, additional slides of the testes were prepared to examine staging of spermatogenesis. The testes were processed, sectioned at 3-4 micrometers, and stained with PAS/haematoxylin (Klinipath,
Duiven, The Netherlands).

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
Mortality / Viability, clinical signs, body weights, sex

GROSS EXAMINATION OF DEAD PUPS:
yes, for external abnormalities; if possible, defects or cause of death were evaluated.

Postmortem examinations (parental animals):

GROSS PATHOLOGY:
All males and females were deprived of food overnight (with a maximum of 24 hours) prior to planned necropsy, but water was provided. Non-selected females were not deprived of food. Animals surviving to scheduled necropsy were deeply anaesthetized using isoflurane (Abbott B.V., Hoofddorp, The Netherlands) and subsequently exsanguinated. Necropsy was conducted on the following days:
- Females which delivered: on Lactation Days 5 and 7.
- Females which failed to deliver (nos. 64): Post-coitum Days 27 (females with evidence of mating)
- Males: Following completion of the mating period (a minimum of 28 days of dose administration).
All animals were subjected to macroscopic examination of the cranial, thoracic and abdominal tissues and organs, with special attention being paid to the reproductive organs. Descriptions of all macroscopic abnormalities were recorded.

ORGAN WEIGHTS:
The following organ weights and terminal body weight were recorded from the following animals on the scheduled day of necropsy:
- selected 5 animals/sex/group: Adrenal glands, Spleen, Brain, Testes, Epididymides, Thymus, Heart, Uterus (including cervix), Kidneys, Prostate, Liver, Seminal vesicles including coagulating glands, Ovaries, Thyroid including parathyroid
- All remaining males: Epididymides, Testes

HISTOPATHOLOGY:
Samples of the following tissues and organs from all animals were collected and fixed in 10% buffered formalin (neutral phosphate buffered 4% formaldehyde solution, Klinipath, Duiven, The Netherlands):
Ovaries, Adrenal glands, (Pancreas), (Aorta), Peyer's patches [jejunum, ileum] if detectable, Brain - cerebellum, mid-brain, cortex, Pituitary gland, Caecum, Preputial gland, Cervix, Prostate gland, Clitoral gland, Rectum, Colon, (Salivary glands - mandibular, sublingual), Coagulation gland, Sciatic nerve, Duodenum, Seminal vesicles, Epididymides, Skeletal muscle, Eyes (with optic nerve (if detectable) and Harderian gland), (Skin), Spinal cord -cervical, midthoracic, lumbar, (Male and Female mammary gland area), Spleen, Femur including joint, Sternum with bone marrow, Heart, Stomach (forestomach and glandular stomach), Ileum, Testes, Jejunum, Thymus, Kidneys, Thyroid including parathyroid if detectable, (Lacrimal gland, exorbital), (Tongue), (Larynx), Trachea, Liver, Urinary bladder, Lung, infused with formalin, Uterus, Lymph nodes - mandibular, mesenteric, Vagina, (Nasopharynx), All gross lesions, (Esophagus)

Tissues/organs mentioned in parentheses were not examined by the pathologist, since no signs of toxicity were noted at macroscopic examination.

From the selected 5 males of the control and high dose group (see § 6.3), and all males suspected to be infertile, additional slides of the testes were prepared to examine staging of spermatogenesis. The testes were processed, sectioned at 3-4 micrometers, and stained with PAS/haematoxylin (Klinipath, Duiven, The Netherlands).

The following slides were examined by a pathologist:
- The preserved organs and tissues of the selected 5 animals/sex of Groups 1 and 4.
- The Additional slides of the testes of all males of Groups 1 and 4 and all males suspected to be infertile or which died before mating to examine staging of spermatogenesis.
- All gross lesions of all animals (all dose groups).
- Kidneys, pituitary and thyroids of all selected males of Groups 2 and 3, based on (possible) treatment-related changes in these organs in Group 4.
- The reproductive organs (cervix, clitoral gland, coagulation gland, epididymides, ovaries, preputial gland, prostate gland, seminal vesicles, testes, uterus, and vagina) of all animals of Groups 1 and 4, and of male 24 (Group 3) that failed to sire and female 64 (Group 3) that failed to deliver healthy pups.

Postmortem examinations (offspring):

Pups surviving to planned termination were killed by decapitation on Days 5 and 7 of lactation. All pups were sexed and descriptions of all external abnormalities were recorded. The stomach was examined for the presence of milk. If possible, defects or cause of death were evaluated.

Statistics:

The following statistical methods were used to analyze the data:
- If the variables could be assumed to follow a normal distribution, the Dunnett-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 was applied if the data could not be assumed to follow a normal distribution.
- The Fisher Exact-test was applied to frequency data.
The following additional methods of statistical analysis were used:
Motor activity data was subjected to the Kruskal-Wallis nonparametric ANOVA test to determine intergroup differences followed by the Wilcoxon test to compare the treated groups to the control group.
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.

Reproductive indices:

Mating index, Fertility index, Conception index, Gestation index, Duration of gestation

Offspring viability indices:

Percentage live males at First Litter Check, Percentage live females at First Litter Check, Percentage of postnatal loss Days 0-4 of lactation, Viability index

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

No clinical signs of toxicity were noted up to 1000 mg/kg bw/day.
Salivation was noted for one, one and five animals in the 62.5, 250 and 1000 mg/kg bw/day groups, respectively. This was considered to be a physiological response rather than a sign of systemic toxicity considering the nature and minor severity of the effect and its time of occurrence (i.e. after dosing). This sign may be related to the taste of the test substance, and was not considered to be toxicologically relevant. Incidental findings that were noted included rales (noted for 1 control animal and 1 animal at 1000 mg/kg bw/day), and alopecia. At the incidence observed, these were not considered to be toxicologically relevant.

Dermal irritation (if dermal study):

not examined

Description (incidence):

No mortality occurred during the study period.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

No toxicologically relevant changes in body weights and body weight gain were noted.
At 1000 mg/kg bw/day, body weight gain was significantly lower for males than controls on Day 8 of the premating period. The difference from controls was only slight and was transient and as such was not considered toxicologically relevant.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

No toxicologically relevant changes in food consumption before or after allowance for body weight were noted.
Females at 1000 mg/kg bw/day had significantly lower relative food consumption on Days 1-4 of lactation. The difference from controls was only slight and was not considered to reflect treatment related toxicity.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No toxicologically relevant changes occurred in haematological parameters of treated rats.
At 1000 mg/kg bw/day, red blood cell distribution width (RDW) was significantly higher than controls. The difference from controls was only slight, and in the absence of effects on any other related haematological parameter like mean corpuscular volume (MCV) and others, this was not considered to be biologically relevant.
At 250 mg/kg bw/day prothrombin time (PT) was significantly lower for males and platelet counts were significantly higher for females, respectively. In the absence of a dose response effect, these were not considered to be treatment related.
Females at 62.5 mg/kg bw/day has significantly increased neutrophil counts with concurrently reduced lymphocyte counts. These differences were attributable to female nos. 57 and 58, and not considfered to be treatment-related, since there was no dose dependancy.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were no toxicologically relevant effects on clinical biochemistry parameters noted up to 1000 mg/kg bw/day.
Total bilirubin was increased for animals of both sexes at 250 and 1000 mg/kg bw/day (not statistically significant for males at 250 mg/kg bw/day). In the absence of any relevant effects on the liver noted at the microscopic examination, and since there was no evidence of increased turnover of red blood cells, the increase was not considered biologically relevant.

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. Both total movements and ambulatory activity were slightly higher for males at 1000 mg/kg bw/day than controls, however, the difference was not significant and in the absence of any relevant clinical signs like hyperactivity, it was not considered to be toxicologically relevant.
All groups showed a similar habituation profile with very high activity in the first interval that decreased over the duration of the test period.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Treatment related microscopic findings were noted in the kidneys, pituitary gland and thyroid glands of male rats.
In the kidneys, hyaline droplets in cortical tubules were noted at a minimal or slight degree in five group 1 (0 mg/kg bw/day), five group 2 (62.5 mg/kg bw/day), at a minimal to moderate degree in five group 3 (250 mg/kg bw/day) and five group 4 (1000 mg/kg bw/day) male animals. The hyaline droplets were considered to represent alpha2μglobulin, a normal protein in male rats which undergoes reabsorption in the proximal cortical tubules. A range of chemicals are known to increase hyaline droplet formation. This protein is not present in higher mammals, including man. The degree of moderate recorded in groups 3 (250 mg bw/day) and 4 (1000 mg/kg bw/day) were above spontaneous background levels but were not accompanied by degenerative tubular alterations, and were thus not considered to be adverse.
Multifocal hypertrophy in the adenohypophysis of the pituitary gland was recorded at a minimal degree in three group 1 (0 mg/kg bw/day), in two group 2 (62.5 mg/kg bw/day), three group 3 (250 mg/kg bw/day) and at minimal (2) slight (1) or moderate (1) degree in four group 4 (1000 mg/kg bw/day) male rats. The moderate degree recorded for one male was above the spontaneous severity of minimal or slight for this finding.
In the thyroid glands diffuse follicular hypertrophy/hyperplasia was seen at minimal degree in one group 1 (0 mg/kg bw/day) and at minimal or slight degree in four group 2 (62.5 mg/kg bw/day), four group 3 (250 mg/kg bw/day) and in three group 4 (1000 mg/kg bw/day) animals. This finding at these degrees of severity is a common background finding in male rats of this age i.e. not adverse.
None of the above alterations achieved statistical significance (p < 0.05) in any group when compared to controls, although a trend test revealed a positive trend (p < 0.05) for hyaline droplets in the kidneys.
There were no microscopic findings in any of the animals suspected of infertility which could explain their lack of reproductive performance.
The remaining recorded microscopic findings were within the range of background pathology encountered in Wistar (Han) rats of this age in this type of study and occurred at similar incidences and severity in both control and treated rats. The spermatogenic staging profiles were normal for all animals assessed.

Histopathological findings: neoplastic:

not examined

Reproductive function / performance (P0)

Reproductive performance:

no effects observed

Description (incidence and severity):

No toxicologically relevant effects on reproductive parameters were noted. All females were pregnant in all groups, though one female at 250 mg/kg bw/day (no. 64) had implantation sites only. The mating, fertility and conception indices, precoital time, and numbers of corpora lutea and implantation sites were unaffected by treatment. The gestation index and duration of gestation were unaffected up to treatment up to 1000 mg/kg bw/day. No signs of difficult or prolonged parturition were noted among the pregnant females. Examination of cage debris of pregnant females revealed no signs of abortion or premature birth and no deficiencies in maternal care were observed.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

Systemic Toxicity

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

2

Dose descriptor:

NOAEL

Remarks:

Fertility

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

Target system / organ toxicity (P0)

Critical effects observed:

no

Results: F1 generation

General toxicity (F1)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Incidental clinical symptoms of pups included pale appearance, no milk in the stomach and hypothermia. The nature and incidence of these clinical signs remained within the range considered normal for pups of this age, and were therefore not considered to be toxicologically relevant.

Dermal irritation (if dermal study):

not examined

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

Two and three pups from the 250 and 1000 mg/kg bw/day groups were found dead or went missing during the first days of lactation. There were no dead or missing pups from the control and 62.5 mg/kg bw/day groups over this time. Missing pups missing were most likely cannibalized. No toxicological relevance was attributed to these dead/missing pups since the mortality incidence did not show a dose-related trend and remained within the range expected for pups of this age.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Body weights of pups were unaffected by treatment up to 1000 mg/kg bw/day.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No milk in the stomach was the only finding noted for pups that were found dead; this was incidental in nature. No milk in the stomach was noted at macroscopic examination for all pups from litters 42, 43, 48, 50, 60, and 72. This was not considered to be treatment related or toxicologically relevant since it occurred mainly for control litters and these pups survived until the scheduled necropsy, indicating they were all sufficiently fed during the first days of lactation. This finding for the animals surviving to the scheduled necropsy is likely secondary to the time when the actual necropsies were performed, and is not attributable to treatment.

Histopathological findings:

not examined

Other effects:

not examined

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Details on results (F1)

Number of dead and living pups at first litter check, postnatal loss, viability index and sex ratio were unaffected by treatment, and clinical signs, body weight and external macroscopic examination did not reveal treatment-related findings.

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects observed

Target system / organ toxicity (F1)

Critical effects observed:

no

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Based on these results, a parental, reproduction and developmental No Observed Adverse Effect Level (NOAEL) of at least 1000 mg/kg bw/day was derived.

Executive summary:

A GLP compliant combined 28-day repeated dose toxicity study with the reproduction/developmental toxicity screening test was performed in male and female Wistar Han rats at dose levels of 62.5, 250 and 1000 mg/kg bw/day. Animals of the control group received the vehicle, propylene glycol, alone.Males were exposed for 29 days, i.e. 2 weeks prior to mating, during mating, and up to termination. Females were exposed for 40-54 days, i.e. during 2 weeks prior to mating, during mating, during postcoitum, and during at least 4 days of lactation. The following observations and examinations were evaluated: mortality / viability, clinical signs (daily), functional observations and locomotor activity (Males: Week 4; females: end of lactation), body weightand food consumption (at least at weekly intervals), clinical pathology (Males: Week 4; females: end of lactation), macroscopy at termination, organ weights and histopathology on a selection of tissues, and reproduction/developmental parameters, consisting of mating, fertility and conception indices, precoital time, number of corpora lutea and implantation sites, gestation index and duration, parturition, maternal care, sex ratio and early postnatal pup development (mortality, clinical signs, body weights and macroscopy). Formulations were analyzed once during the study to assess accuracy, homogeneity and stability. Accuracy, homogeneity and stability of formulations were demonstrated by analyses.

At 1000 mg/kg bw/day, there was an increased severity of multifocal hypertrophy in the adenohypophysis of the pituitary gland in males. The severity (moderate) was higher than background for a single male. No toxicologically relevant changes were noted in any of the remaining parental parameters investigated in this study (i.e. clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination and organ weights). No reproduction toxicity was observed up to the highest dose level tested (1000 mg/kg bw/day).

In conclusion, treatment with the test article by oral gavage in male and female Wistar Han rats at dose levels of 62.5, 250 and 1000 mg/kg body weight/day revealed histological findings at 1000 mg/kg body weight/day characterized by an increased severity of multifocal hypertrophy in the adenohypophysis of the pituitary gland in males only. As this was higher thanbackground in only a single male, when taken together in the absence of any other toxicologically relevant effects, the NOAEL was considered to be 1000 mg/kg bw/day for parental animals. No reproduction and developmental toxicity was observed for treatment up to 1000 mg/kg body weight/day. Based on these results, a parental, reproduction and developmental No Observed Adverse Effect Level (NOAEL) of at least 1000 mg/kg bw/day was derived.