Reaction mass of 1H-Benzotriazole-1-methanamine, N,N-bis(2-ethylhexyl)-6-methyl- and 2H-Benzotriazole-2-methanamine, N,N-bis(2-ethylhexyl)-5-methyl- and N,N-bis(2-ethylhexyl)-4-methyl-1H-benzotriazole-1-methylamine and 2H-Benzotriazole-2-methanamine, N,N-bis(2-ethylhexyl)-4-methyl- and N,N-bis(2-ethylhexyl)-5-methyl-1H-benzotriazole-1-methylamine

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

A combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (OECD 422) revealed no reproductive toxicity up to the highest dose level tested. The NOAEL for reproductive toxicity was therefore 150 mg/kg bw/day. The NOAEL for parental toxicity was 45 mg/kg.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 June 2012 - 09 August 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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)

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3650 (Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test)

GLP compliance:

yes

Remarks:

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

Limit test:

no

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, in the dark

Species:

rat

Strain:

Wistar

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: Approximately 11 weeks
- Weight at study initiation: Males: 306-311g, Females: 199-204 g
- 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 were 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. General: Sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment/nesting material (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) were supplied. During locomotor activity monitoring, animals were housed individually in a Hi-temp polycarbonate cage (Ancare corp., USA; dimensions: 48.3 x 26.7 x 20.3 cm) without cage-enrichment or bedding material.
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water: Free access to tap-water.
- Acclimation period: At least 5 days prior to start of treatment

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

Route of administration:

oral: gavage

Vehicle:

other: Solution of 0.5% carboxymethyl cellulose and 0.1% Tween-80 in water

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 the mean specific gravity of the test substance (0.95 g/cm3). No adjustment was made for the purity of the test substance, since it was considered nearly 100%.

VEHICLE
- Justification for use and choice of vehicle: Based on trial formulations performed at WIL Research Europe.
- Amount of vehicle: 5 mL/kg body weight

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.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples (0.5 mL) were taken using a pipette (a clean pipette tip was used for every group), and were weighed on an analytical balance at 4 decimals precision. During sampling, formulations were placed on a magnetic stirrer. Immediately after sampling (accuracy and homogeneity samples) or after 5 hours at room temperature under normal laboratory light conditions (stability samples), samples were stored on dry ice. Samples remained on dry ice until receipt at ABL B.V., The Netherlands, where samples were stored at ≤ -70°C until analysis. Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations). Stability in vehicle over 5 hours at room temperature under normal laboratory light conditions 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 42-45 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). Females 45 (Group 1), 53 (Group 2) and 78 (Group 4) 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 5 hours difference between the earliest and latest dose.

Dose / conc.:

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

Dose / conc.:

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

Dose / conc.:

150 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: In a previous dose range finding study (Project 499974; BASF Project 01R0608/11X398) groups of 4 male and 4 female Crl:WI(Han) rats received Irgamet 39 by oral gavage for a period of 14 days at the dose levels of 0, 100, 300, or 1000 mg/kg bw/day. All females and males at 1000 mg/kg bw/day were euthanized on Days 4 and 5, respectively, for humane reasons. At 300 mg/kg bw/day, one female was found dead on Day 7, and the remaining animals were euthanized on Day 8 due to poor general conditions. In both dose groups, the predominant clinical signs consisted of lethargy, hunched posture, uncoordinated movements and piloerection. Partially, the clinical signs showed a dose-relationship with regards to onset and severity. Body weight loss, together with reduced food intake was recorded in a dose-related manner. Gross necropsy findings were noted for two females at 1000 mg/kg bw/day only. These included gelatinous contents in the gastro-intestinal tract, several dark-red foci on the caecum and/or glandular mucosa of the stomach, thickened glandular mucosa of the stomach, reduced size of the caecum and/or dark-red discoloration of the ileo-caecal valve.
- Treatment: By oral gavage, using a plastic feeding tube. Formulations were placed on a magnetic stirrer during dosing.
- Parturition: The females were allowed to litter normally. Day 1 of lactation was defined as the day when a litter was found completed (i.e. membranes and placentas cleaned up, nest build up and/or feeding of pups started). Females that were littering were left undisturbed.

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: At least twice daily.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily
Detailed clinical observations were made in all animals, at least immediately (0-15 min) after dosing (based on results of the dose range finding study, Project 499974; BASF Project 01R0608/11X398). 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. The time of onset, grade and duration of any observed sign was recorded. Signs were graded for severity and the maximum grade was predefined at 3 or 4. Grades were coded as slight (grade 1), moderate (grade 2), severe (grade 3) and very severe (grade 4). For certain signs, only its presence (grade 1) or absence (grade 0) was scored.

BODY WEIGHT: Yes
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 AND COMPOUND INTAKE:
Subjective appraisal was maintained during the study, but no quantitative investigation was introduced as no treatment related effect was suspected.

LABORATORY INVESTIGATIONS
Blood samples were collected from the selected 5 animals/sex/group under anaesthesia using isoflurane (Abbott B.V., Hoofddorp, The Netherlands) between 7.00 and 10.30 a.m. The animals were deprived of food overnight (with a maximum of 24 hours) before blood sampling, but water was provided. Blood samples were drawn from the retro-orbital sinus and collected into tubes (Greiner Bio-One GmbH, Kremsmünster, Austria) prepared with EDTA for haematological parameters (0.5 mL), with citrate for clotting tests (0.45 mL) and Li-heparin treated tubes for clinical biochemistry parameters (0.5 mL). An additional blood sample (0.25 mL) was collected into untreated tubes for determination of bile acids. Furthermore, from the selected 5 animals/sex/group an additional blood sample (0.5 mL) was collected into serum tubes for possible future measurement of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). After clotting and centrifugation, serum samples were stored at ≤-75°C. Since histopathological examination of the thyroid glands did not reveal any treatmentrelated changes, all samples were discarded at finalization of the study report without further investigation.

HAEMATOLOGY: Yes
The following haematology parameters were determined in blood prepared with EDTA as an anticoagulant, using the ADVIA® 120 Hematology System (Siemens Healthcare Diagnostics B.V., Breda, The Netherlands): 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. The following clotting parameters were determined in plasma prepared with citrate as anti-coagulant, using the STA Compact® (Diagnostica Stago S.A.S., Asnières, France): Prothrombin Time, Activated Partial Thromboplastin Time.

CLINICAL CHEMISTRY: Yes
The following clinical biochemistry parameters were determined using the AU400® Chemistry System (Beckman Coulter Nederland B.V., Woerden, The Netherlands). All parameters were determined in plasma, except for bile acids which were determined in serum: Alanine aminotransferase, Aspartate aminotransferase, Alkaline Phosphatase, Total protein, Albumin, Total Bilirubin, Bile acids, Urea, Creatinine, Glucose, Cholesterol, Sodium, Potassium, Chloride, Calcium, Inorganic Phosphate, Bile acids.

NEUROBEHAVIOURAL EXAMINATION: Yes
The following tests were performed on the selected 5 animals/sex/group: hearing ability, pupillary reflex, static righting reflex, grip strength, locomotor activity (recording period: 1-hour under normal laboratory light conditions, using a computerized monitoring system, Kinder Scientific LLC, Poway, USA). Total movements and ambulations are reported. Ambulations represent movements characterized by a relocation of the entire body position like walking, whereas total movements represent all movements made by the animals, including ambulations but also smaller or more fine movements like grooming, weaving or movements of the head. During motor activity monitoring, all animals were caged individually (pups were housed in their home cages and kept warm using bottles filled with warm water). The selected males were tested during Week 4 of treatment and the selected females were tested towards the end of the scheduled lactation period (all before blood sampling). These tests were performed as soon as possible after observation for clinical signs (incl. arena observation, if applicable), and before blood sampling.

Sperm parameters (parental animals):

Of all 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:

- Mortality / Viability: The numbers of live and dead pups on Day 1 of lactation and daily thereafter were determined. If possible, defects or cause of death were evaluated.
- Clinical signs: At least once daily, detailed clinical observations were made for all animals.
- Body weights: Live pups were weighed on Days 1 and 4 of lactation.
- Sex: Sex was determined for all pups on Days 1 and 4 of lactation.

Postmortem examinations (parental animals):

- Necropsy: All males, the selected females/group 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: Lactation Days 5-7, Females which failed to deliver: Post-coitum Day 25-26 (females with evidence of mating). Spontaneous deaths: as soon as possible after death and always within 24 hours. 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. The numbers of former implantation sites and corpora lutea were recorded for all paired females (for females which failed to deliver: In case no macroscopically visible implantation sites were present, nongravid uteri were stained using the Salewski technique in order to detect any former implantation sites).

Samples of the following tissues and organs were collected from all animals and fixed in 10% buffered formalin (neutral phosphate buffered 4% formaldehyde solution, Klinipath, Duiven, The Netherlands): Adrenal glands, (Aorta), Brain - cerebellum, mid-brain, cortex, Caecum, Cervix, Clitoral gland, Colon, Coagulation gland, Duodenum, Epididymides, Eyes (with optic nerve (if detectable) and Harderian gland), (Male and Female mammary gland area), Femur including joint, Heart, Ileum, Jejunum, Kidneys, (Lacrimal gland, exorbital), (Larynx), Liver, Lung, infused with formalin, Lymph nodes - mandibular, mesenteric, (Nasopharynx), (Esophagus), Ovaries, (Pancreas), Peyer's patches [jejunum, ileum] if detectable, Pituitary gland, Preputial gland, Prostate gland, Rectum, (Salivary glands - mandibular, sublingual), Sciatic nerve, Seminal vesicles, Skeletal muscle, (Skin), Spinal cord -cervical, midthoracic, lumbar, Spleen, Sternum with bone marrow, Stomach (forestomach and glandular stomach), Testes, Thymus, Thyroid including parathyroid if detectable, (Tongue), Trachea, Urinary bladder, Uterus, Vagina, All gross lesions. The epididymides, eyes and testes were fixed in modified Davidson's solution and Milli-Ro water and transferred to formalin after fixation for at least 24 hours. Tissues/organs mentioned in parentheses were not examined by the pathologist, since no signs of toxicity were noted at macroscopic examination.

- Organ weights: The following organ weights and terminal body weight were recorded from the selected 5 animals/sex/group on the scheduled day of necropsy: Adrenal glands, Brain, Epididymides, Heart, Kidneys, Liver, Ovaries, Spleen, Testes, Thymus, Uterus (including cervix), Prostate (weighed when fixed for at least 24 hours), Seminal vesicles including coagulating glands (weighed when fixed for at least 24 hours), Thyroid including parathyroid (weighed when fixed for at least 24 hours). All remaining males: Epididymides, Testes.

- Histotechnology: All organ and tissue samples, as defined under Histopathology (following section), were processed, embedded and cut at a thickness of 2-4 micrometers and stained with haematoxylin and eosin (Klinipath, Duiven, The Netherlands).

- Histopathology: The following slides were examined by a pathologist: (1) The preserved organs and tissues of the selected 5 animals/sex of Groups 1 and 4. (2) 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. (3) All gross lesions of all animals (all dose groups). (4) The preserved organs and tissues of the animals of the two Group 4 females that either died spontaneously or were euthanized due to a total litter loss. (5) The spleen and thymus of all selected 5 females of Groups 2 and 3, based on (possible) treatment-related changes in these organs in Group 4. (6) The reproductive organs (cervix, clitoral gland, coagulation gland, epididymides, ovaries, preputial gland, prostate gland, seminal vesicles, testes, uterus, and vagina) of male no. 31 (Group 4) and female no. 71 (Group 4) that had a total litter loss.

Postmortem examinations (offspring):

Pups surviving to planned termination were killed by decapitation on Days 5-7 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 (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 if the data could not be assumed to follow a normal distribution.
- The Fisher Exact-test was applied to frequency data.
- 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:

For each group, the following calculations were performed:
- Mating index (%) = (Number of females mated / Number of females paired) x 100
- Fertility index (%) = (Number of pregnant females / Number of females paired) x 100
- Conception index (%) = (Number of pregnant females / Number of females mated) x 100
- Gestation index (%) = (Number of females bearing live pups / Number of pregnant females) x 100
- Duration of gestation = Number of days between confirmation of mating and the beginning of parturition

Offspring viability indices:

For each group, the following calculations were performed:
- Percentage live males at First Litter Check = (Number of live male pups at First Litter Check / Number of live pups at First Litter Check) x 100
- Percentage live females at First Litter Check = (Number of live female pups at First Litter Check / Number of live pups at First Litter Check) x 100
- Percentage of postnatal loss Days 0-4 of lactation = (Number of dead pups on Day 4 of lactation / Number of live pups at First Litter Check) x 100
- Viability index = (Number of live pups on Day 4 post partum / Number of pups born alive) x 100

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

For females at 150 mg/kg bw/day hunched posture, piloerection and pale faeces were noted mainly during the last two weeks of treatment.
No clinical signs of toxicity were noted for females at 15 and 45 mg/kg bw/day and males up to 150 mg/kg bw/day.
Salivation seen after dosing among females of the 150 mg/kg bw/day dose group towards the end of the treatment period 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 irritancy/taste of the test substance.
Incidental findings that were noted for a single female each at 15, 45 and 150 mg/kg bw/day included hunched posture, salivation and purple discolouration of the ear, respectively. In addition, scabbing was recorded for two males at 150 mg/kg bw/day. These findings occurred within the range of background findings to be expected for rats of this age and strain which are housed and treated under the conditions in this study. At the low incidence observed, these were considered signs of no toxicological relevance.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No mortalities occurred that were considered to be a direct cause of treatment with Irgamet 39 up to 150 mg/kg bw/day.
One female at 150 mg/kg bw/day died during parturition on Day 21 post-coitum (ten healthy pups were already delivered). No clinical signs were noted. Food consumption (absolute and relative to body weight) was only slightly lower from Days 14-20 post-coitum with no effects on body weight. At necropsy, three fully developed fetuses were discovered in the right uterus horn and watery cloudy fluid was found in the lungs which correlated with the finding of alveolar proteinaceous fluid at the microscopic level. These necropsy findings were indicative for parturition difficulties that likely resulted in circulatory failure. In addition, her spleen was reduced in size and many dark red foci were noted on the thymus.
Another female at 150 mg/kg bw/day had to be euthanized due to a total litter loss on Day 2 of lactation. Clinical signs were recorded from the end of the post-coitum phase onwards and consisted of hunched posture, piloerection and pale faeces. This female had the lowest body weight and the lowest food consumption in this group. At necropsy, the only finding was a smaller thymus. No mortality occurred at the lower doses of 45 and 15 mg/kg bw/day or in the control group.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

There was a trend towards lower body weights as compared to controls for males and females at 150 mg/kg bw/day during the post-coitum phase, reaching statistical significance in females on Day 20 post-coitum and during the subsequent phase of lactation as well as in males at termination. Body weight gains were significantly lower in females from Days 4-20 post-coitum. Body weight gain between Day 0 and 20 post-coitum was 74 g versus 104 g in controls. No toxicologically relevant changes in body weights and body weight gain were noted up to 45 mg/kg bw/day.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A lower food consumption (absolute and relative to body weight) was recorded for females at 150 mg/kg bw/day as compared to controls during the entire treatment period, though differences were not always statistically significant.
For females up to 45 mg/kg bw/day and males up to 150 mg/kg bw/day, food consumption was in the same range as for control animals. For one cage with five males (cage no. 7; male nos. 31-35) at 150 mg/kg bw/day food consumption (absolute and relative to body weight) was slightly lower during the first week of treatment. However, changes were only slight and transient, and no comparable effect was noted for the other cage with high dose males. Therefore, this finding was not considered to be toxicologically relevant.

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):

Haematological parameters of treated rats were considered not to have been affected by treatment up to 150 mg/kg bw/day.
Any statistically significant changes observed were considered to be of no toxicological relevance as no treatment-related distribution could be established, changes occurred in the absence of corroborating effects in related parameters and remained within the range considered normal for rats of this age and strain. These changes included a decreased prothrombin time (PT) for males at 150 mg/kg bw/day and increased values for white blood cell count (WBC), mean corpuscular haemoglobin concentration (MCHC) and activated partial prothrombin time (APTT) for females at 45 and/or 150 mg/kg bw/day.

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 up to 150 mg/kg bw/day.
Any statistically significant changes observed were considered to be of no toxicological relevance as no treatment-related distribution could be established, changes occurred in the absence of corroborating effects in related parameters, remained within the range considered normal for rats of this age and strain and/or were the result of relatively low control values. These changes included increased concentrations of potassium for males at 45 mg/kg bw/day and increased concentrations of creatinine, bile acids and inorganic phosphates for females at 15, 45 and/or 150 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 selected animals.
The variation in motor activity did not indicate a relation with treatment. All groups showed a similar habituation profile with very high activity in the first interval that decreased over the duration of the test period.
For males, there was a trend towards lower total movements with increasing dose (not statistically significant). However, all values remained within the normal range of biological variation. Moreover, there were no corroborative findings during clinical observations and no comparable change was seen for females. Therefore, this finding was considered to be a chance finding rather than a sign of toxicity.

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

There were treatment-related microscopic findings in the thymus and spleen of females.
Thymus: Lymphoid atrophy (involution) was present in 4/7 (2 minimal, 1 slight, 1 moderate) females treated at 150 mg/kg bw/day, and did correlate with low thymus weights in females 73, 76 and 78.
Spleen: A decreased severity of hemopoietic foci, primarily erythropoiesis was present in 6/6 (4 minimal, 1 slight, 1 moderate) females treated at 150 mg/kg bw/day compared to normal levels in 5/5 control (1 minimal, 1 slight, 2 moderate, 1 marked), 5/5 15 mg/kg bw/day (2 slight, 1 moderate, 2 marked) and 5/5 45 mg/kg bw/day (1 minimal, 3 moderate, 1 marked) treated female rats.
All other microscopic findings recorded were considered to be within the normal range of background pathology encountered in Wistar-Han rats of this age.
There were two Group 3 and four Group 4 rats that failed to mate, conceive, sire or deliver healthy offspring and were therefore selected for histopathological examination of the reproductive organs. No cause of infertility was found for these animals.
The total litter loss observed for one female of group 4 (150 mg/kg bw/day) could not be explained based on the microscopic examination. There was proteinaceous fluid (milk) present in the mammary gland of this female.
The assessment of the integrity of the spermatogenetic cycle did not provide any evidence of impaired spermatogenesis. There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item.

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Description (incidence and severity):

REPRODUCTION DATA
No toxicologically relevant effects on reproductive parameters were noted.
Mating, fertility and conception indices, precoital time, and number of corpora lutea and implantation sites were considered to be unaffected by treatment.
All females were mated within four days. However, one female at 45 and 150 mg/kg bw/day each appeared to be not pregnant. In the absence of any morphological findings in the reproductive organs of these two females and her male partners which could be attributed to the test item, it was considered a chance finding rather than a treatment related effect.
A trend towards a slightly lower mean number of implantation sites was noted at 150 mg/kg bw/day (not statistically relevant). One female (78) had 18 corpora lutea but carried only 6 implantations. This finding was not considered to be toxicologically relevant as it was an isolated observation and all other females of the high dose group carried 10-14 implantation sites which was within the normal range of biological variation.

GESTATION
The gestation index and duration of gestation were unaffected up to 150 mg/kg bw/day. The gestation index was 100% for females of the control, 15 and 45 mg/kg bw/day groups. The slightly lower gestation index of 88.9 % for the 150 mg/kg bw/day group was caused by the fact that one female died during littering. This finding was not considered to be a direct cause of treatment with the test article.

PARTURITION/MATERNAL CARE
Parturition and subsequent maternal care were considered to be unaffected by treatment up to 150 mg/kg bw/day. One female at 150 mg/kg bw/day died after she had delivered ten healthy pups. At necropsy, three fully developed fetuses were found in the right uterus horn at necropsy. Furthermore, watery cloudy fluid was noted in the lungs which correlated with the finding of alveolar proteinaceous fluid at the microscopic level. These findings were indicative for severe parturition difficulties that resulted in circulatory failure. As no signs of difficult or prolonged parturition were noted for the remaining pregnant females in this group and complications during parturition are incidentally seen in this type of study, the sudden death of the single high dose female was considered not to be treatment related. Examination of cage debris of pregnant females revealed no signs of abortion or premature birth. For one female (71) at 150 mg/kg bw/day it was not clear if deficiencies in maternal care had occurred, as none of her pups that was alive at first litter check had milk in the stomach and a total litter loss was recorded on lactation Day 2. However, proteinaceous fluid (milk) was present her mammary glands. It should be noted that during the post-coitum phase lower body weights and food consumption were recorded for this female as compared to the remaining high dose females. This may indicate that this female was in a poor condition.

Key result

Dose descriptor:

NOAEL

Remarks:

parental

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

body weight and weight gain

food consumption and compound intake

organ weights and organ / body weight ratios

histopathology: non-neoplastic

Key result

Dose descriptor:

NOAEL

Remarks:

reproduction

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No reproduction toxicity was observed up to the highest dose level tested (150 mg/kg bw/day).

Key result

Critical effects observed:

no

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

At first litter check, absence of milk in the stomach was noted for all alive pups of one litter (71) at 150 mg/kg bw/day. On the next morning, these pups were either found dead or missing. No abnormalities were noted for these dead pups. Pale or lean appearance were recorded for two single pups. The nature and incidence of these clinical signs remained within the range considered normal for pups of this age, and were therefore considered to be of no toxicological relevance.

Dermal irritation (if dermal study):

not examined

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

The number of dead pups at first litter check was unaffected by treatment up to 150 mg/kg bw/day. Postnatal loss was significantly higher at 150 mg/kg bw/day. The number of pups that were found dead or missing during the first days of lactation were 1, 0, 2 and 11, respectively, in the control, 15, 45 and 150 mg/kg bw/day groups. From the eleven pups in the high dose group, eight came from the single dam who had a total litter loss. The last three pups were distributed over three litters. In addition, a litter of ten pups had to be euthanized because their mother had died spontaneously. Hence, their death was not directly related to treatment. Due to the relatively high post natal loss the viability index for the 150 mg/kg bw/day group reached only 84.9% as compared to 99.1%, 100.0% and 98.3% for the control, 15 and 45 mg/kg bw/day groups, respectively.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Mean pup body weights were in general lower in litters of the 150 mg/kg bw/day group as compared to control litters, except for pups in litters 77 and 78. This difference was attributed to the relatively low size of the latter litters (5-6 pups versus 10-12 pups). The lower pup body weights were likely secondary to the lower body weight gain recorded for their dams as compared to controls during the post-coitum and lactation period. In line with this is the fact that the treated pups gained a comparable percentage of weight as controls from postnatal Days 1-4 (48 versus 51% gain for pups from the 150 mg/kg bw/day and control groups, respectively). As such, the differences in pup body weights at 150 mg/kg bw/day were not considered to be toxicologically relevant.

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:

not examined

Histopathological findings:

not examined

Other effects:

no effects observed

Description (incidence and severity):

MACROSCOPY
For one pup at 45 mg/kg bw/day that was found dead on Day 5 of lactation beginning autolysis and absence of milk in the stomach were noted. One control pup that survived until planned necropsy had a lean appearance. The nature and incidence of these findings remained within the range considered normal for pups of this age, and were therefore considered to be of no toxicological relevance. No milk in the stomach was noted at macroscopic examination for all pups from litters 41, 47, 52, 60, 61, 62, 66, 67, 74, 77 and 78. This was not considered to be treatment related or toxicologically relevant since no treatment-related distribution could be established. Moreover, pups from these litters survived until scheduled necropsy, indicating they were all sufficiently fed during the first days of lactation. Therefore, this finding was likely secondary to the time when the actual necropsies were performed. For all these litters it was not attributable to treatment.

SEX RATIO:
The sex ratio was unaffected by treatment.

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

EARLY POSTNATAL DEVELOPMENT

There were significantly fewer living pups at first litter check at 150 mg/kg bw/day. Mean litter sizes were 11.6, 11.4, 12.9 and 9.1 pups for the control, 15, 45 and 150 mg/kg bw/day groups, respectively. In total, only 73 pups (8 litters) were born in the 150 mg/kg bw/day group as compared to 116 (10 litters), 114 (10 litters) and 116 pups (9 litters) in the control, 15 and 45 mg/kg bw/day groups. This number does not include the 10 pups from the dam at 150 mg/kg bw/day that died during littering. A compound-related effect cannot be ruled out. However, the low number of animals (8) precludes a final assessment.

Key result

Dose descriptor:

NOAEL

Remarks:

developmental

Generation:

F1

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Smaller mean litter size at first litter check was observed at 150 mg/kg.

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

Formulation analyses revealed that the high concentration was prepared accurately. The low and mid concentrations were slightly higher than nominal (119% and 116%, respectively). The mid and high concentrations were homogeneously (i.e. coefficient of variation ≤ 10%), whereas the low concentration was not homogeneous (i.e. coefficient of variation of 20.9%). No test compound was detected in the vehicle formulation. The inhomogeneity of the formulation for Group 2 (15 mg/kg bw/day) had no impact on the outcome of this study as the No Observed Adverse Effect Levels (NOAEL) derived were at 45 or 150 mg/kg bw/day (see further below). Formulations at the entire range were stable when stored at room temperature under normal laboratory light conditions for at least 5 hours (i.e. relative difference ≤ 10%).

Conclusions:

Based on the results presented, the following No Observed Adverse Effect Levels (NOAEL) were derived:
Parental NOAEL: 45 mg/kg bw/day; Reproduction NOAEL: 150 mg/kg bw/day; Developmental NOAEL: 45 mg/kg bw/day

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 15, 45 and 150 mg/kg bw/day. Animals of the control group received the vehicle, 0.5% carboxymethyl cellulose and 0.1% Tween-80 in water, alone. Males were exposed for 29 days, i.e. 2 weeks prior to mating, during mating, and up to termination. Females were exposed for 42-45 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 (Week 4 (males); end of lactation (females)), body weight and food consumption (at least at weekly intervals), clinical pathology (Week 4 (males); end of lactation (females)), 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.

Toxicity was noted at 150 mg/kg bw/day. For females, it was characterized by clinical signs, reduced body weight gains with lower food consumption, and slightly reduced thymus organ weight. The slightly lower thymus organ weights were in line with the observation of lymphoid atrophy (involution) present in 4 out of the 7 examined females in this high dose group (2 minimal, 1 slight, 1 moderate). Further microscopic findings consisted of lower mean grade of hematopoietic foci in the spleen of females at 150 mg/kg bw/day. Slightly lower body weight gains were also observed for males at 150 mg/kg bw/day. No toxicologically significant changes were noted in any of the remaining parental parameters investigated in this study (i.e. mortality, functional observations, haematology, clinical biochemistry, macroscopic abnormalities). There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item. No reproduction toxicity was observed up to the highest dose level tested (150 mg/kg bw/day). Smaller mean litter size at first litter check was noted at 150 mg/kg. A compound-related effect cannot be ruled out. However, the low number of animals (n=8) precludes a final assessment. The lower pup body weights at 150 mg/kg bw/day were considered secondary to the reduced body weights of their dams. No toxicologically significant changes were noted in any of the remaining developmental parameters investigated in this study (i.e. duration of gestation, parturition and macroscopy). Pup development was unaffected by treatment at 15 or 45 mg/kg bw/day. In conclusion, treatment with test material by oral gavage in male and female Wistar Han rats at dose levels of 15, 45 or 150 mg/kg bw/day revealed parental toxicity at 150 mg/kg bw/day. No reproduction toxicity was observed for treatment up to 150 mg/kg bw/day. Developmental toxicity occurred at 150 mg/kg bw/day. Based on these results, the following No Observed Adverse Effect Levels (NOAEL) were derived:

Parental NOAEL: 45 mg/kg bw/day;

Reproduction NOAEL: 150 mg/kg bw/day;

Developmental NOAEL: 45 mg/kg bw/day.

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

Quality of whole database:

GLP and guideline compliant.

Additional information

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 15, 45 and 150 mg/kg bw/day by oral gavage. Animals of the control group received the vehicle alone. Males were exposed for 2 weeks prior to mating, during mating, and up to termination (for 29 days). The females were exposed for 2 weeks prior to mating, during mating, during post-coitum, and at least 4 days of lactation (for 42-45 days).

Toxicity was noted at 150 mg/kg bw/day. For females, it was characterized by clinical signs, reduced body weight gains with lower food consumption, and slightly reduced thymus organ weight. The slightly lower thymus organ weights were in line with the observation of lymphoid atrophy (involution) present in 4 out of the 7 examined females in this high dose group (2 minimal, 1 slight, 1 moderate). Further microscopic findings consisted of lower mean grade of hematopoietic foci in the spleen of females at 150 mg/kg bw/day. Slightly lower body weight gains were also observed for males at 150 mg/kg bw/day. No toxicologically significant changes were noted in any of the remaining parental parameters investigated in this study (i.e. mortality, functional observations, haematology, clinical biochemistry, macroscopic abnormalities). There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item. No reproduction toxicity was observed up to the highest dose level tested (150 mg/kg bw/day). Smaller mean litter size at first litter check was noted at 150 mg/kg. A compound-related effect cannot be ruled out. However, the low number of animals (n=8) precludes a final assessment. The lower pup body weights at 150 mg/kg bw/day were considered secondary to the reduced body weights of their dams. No toxicologically significant changes were noted in any of the remaining developmental parameters investigated in this study (i.e. duration of gestation, parturition and macroscopy). Pup development was unaffected by treatment at 15 or 45 mg/kg bw/day. In conclusion, treatment with test material by oral gavage in male and female Wistar Han rats at dose levels of 15, 45 or 150 mg/kg bw/day revealed parental toxicity at 150 mg/kg bw/day. Based on these results, the following No Observed Adverse Effect Levels (NOAEL) were derived:

Parental NOAEL: 45 mg/kg bw/day;

Reproduction NOAEL: 150 mg/kg bw/day;

Developmental NOAEL: 45 mg/kg bw/day.

Effects on developmental toxicity

Description of key information

A combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (OECD 422) revealed slight developmental toxicity at the highest dose level tested, which also caused maternal toxicity. The NOAEL for developmental and parental toxicity was therefore 45 mg/kg bw/day.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 June 2012 - 09 August 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3650 (Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test)

GLP compliance:

yes

Remarks:

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

Limit test:

no

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, in the dark

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Approximately 11 weeks
- Weight at study initiation: Males: 306-311g, Females: 199-204g
- 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 were 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. General: Sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment/nesting material (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) were supplied. During locomotor activity monitoring, animals were housed individually in a Hi-temp polycarbonate cage (Ancare corp., USA; dimensions: 48.3 x 26.7 x 20.3 cm) without cage-enrichment or bedding material.
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water: Free access to tap-water.
- Acclimation period: At least 5 days prior to start of treatment

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

Route of administration:

oral: gavage

Vehicle:

other: Solution of 0.5% carboxymethyl cellulose and 0.1% Tween-80 in water

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 the mean specific gravity of the test substance (0.95 g/cm3). No adjustment was made for the purity of the test substance, since it was considered nearly 100%.

VEHICLE
- Justification for use and choice of vehicle: Based on trial formulations performed at WIL Research Europe.
- Amount of vehicle: 5 mL/kg body weight

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples (0.5 mL) were taken using a pipette (a clean pipette tip was used for every group), and were weighed on an analytical balance at 4 decimals precision. During sampling, formulations were placed on a magnetic stirrer. Immediately after sampling (accuracy and homogeneity samples) or after 5 hours at room temperature under normal laboratory light conditions (stability samples), samples were stored on dry ice. Samples remained on dry ice until receipt at ABL B.V., The Netherlands, where samples were stored at ≤-70°C until analysis. Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations). Stability in vehicle over 5 hours at room temperature under normal laboratory light conditions 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%.

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.

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 42-45 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). Females 45 (Group 1), 53 (Group 2) and 78 (Group 4) 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 5 hours difference between the earliest and latest dose.

Duration of test:

14 days

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

300 mg/kg bw/day (nominal)

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: In a previous dose range finding study (Project 499974; BASF Project 01R0608/11X398) groups of 4 male and 4 female Crl:WI(Han) rats received Irgamet 39 by oral gavage for a period of 14 days at the dose levels of 0, 100, 300, or 1000 mg/kg bw/day. All females and males at 1000 mg/kg bw/day were euthanized on Days 4 and 5, respectively, for humane reasons. At 300 mg/kg bw/day, one female was found dead on Day 7, and the remaining animals were euthanized on Day 8 due to poor general conditions. In both dose groups, the predominant clinical signs consisted of lethargy, hunched posture, uncoordinated movements and piloerection. Partially, the clinical signs showed a dose-relationship with regards to onset and severity. Body weight loss, together with reduced food intake was recorded in a dose-related manner. Gross necropsy findings were noted for two females at 1000 mg/kg bw/day only. These included gelatinous contents in the gastro-intestinal tract, several dark-red foci on the caecum and/or glandular mucosa of the stomach, thickened glandular mucosa of the stomach, reduced size of the caecum and/or dark-red discoloration of the ileo-caecal valve.
- Treatment: By oral gavage, using a plastic feeding tube. Formulations were placed on a magnetic stirrer during dosing.
- Parturition: The females were allowed to litter normally. Day 1 of lactation was defined as the day when a litter was found completed (i.e. membranes and placentas cleaned up, nest build up and/or feeding of pups started). Females that were littering were left undisturbed.

Maternal 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: At least twice daily.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily
Detailed clinical observations were made in all animals, at least immediately (0-15 min) after dosing (based on results of the dose range finding study, Project 499974; BASF Project 01R0608/11X398). 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. The time of onset, grade and duration of any observed sign was recorded. Signs were graded for severity and the maximum grade was predefined at 3 or 4. Grades were coded as slight (grade 1), moderate (grade 2), severe (grade 3) and very severe (grade 4). For certain signs, only its presence (grade 1) or absence (grade 0) was scored.

BODY WEIGHT: Yes
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 AND COMPOUND INTAKE:
Subjective appraisal was maintained during the study, but no quantitative investigation was introduced as no treatment related effect was suspected.

LABORATORY INVESTIGATIONS
Blood samples were collected from the selected 5 animals/sex/group under anaesthesia using isoflurane (Abbott B.V., Hoofddorp, The Netherlands) between 7.00 and 10.30 a.m. The animals were deprived of food overnight (with a maximum of 24 hours) before blood sampling, but water was provided. Blood samples were drawn from the retro-orbital sinus and collected into tubes (Greiner Bio-One GmbH, Kremsmünster, Austria) prepared with EDTA for haematological parameters (0.5 mL), with citrate for clotting tests (0.45 mL) and Li-heparin treated tubes for clinical biochemistry parameters (0.5 mL). An additional blood sample (0.25 mL) was collected into untreated tubes for determination of bile acids. Furthermore, from the selected 5 animals/sex/group an additional blood sample (0.5 mL) was collected into serum tubes for possible future measurement of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). After clotting and centrifugation, serum samples were stored at ≤-75°C. Since histopathological examination of the thyroid glands did not reveal any treatmentrelated changes, all samples were discarded at finalization of the study report without further investigation.

HAEMATOLOGY: Yes
The following haematology parameters were determined in blood prepared with EDTA as an anticoagulant, using the ADVIA® 120 Hematology System (Siemens Healthcare Diagnostics B.V., Breda, The Netherlands): 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. The following clotting parameters were determined in plasma prepared with citrate as anti-coagulant, using the STA Compact® (Diagnostica Stago S.A.S., Asnières, France): Prothrombin Time, Activated Partial Thromboplastin Time.

CLINICAL CHEMISTRY: Yes
The following clinical biochemistry parameters were determined using the AU400® Chemistry System (Beckman Coulter Nederland B.V., Woerden, The Netherlands). All parameters were determined in plasma, except for bile acids which were determined in serum: Alanine aminotransferase, Aspartate aminotransferase, Alkaline Phosphatase, Total protein, Albumin, Total Bilirubin, Bile acids, Urea, Creatinine, Glucose, Cholesterol, Sodium, Potassium, Chloride, Calcium, Inorganic Phosphate, Bile acids.

NEUROBEHAVIOURAL EXAMINATION: Yes
The following tests were performed on the selected 5 animals/sex/group: hearing ability, pupillary reflex, static righting reflex, grip strength, locomotor activity (recording period: 1-hour under normal laboratory light conditions, using a computerized monitoring system, Kinder Scientific LLC, Poway, USA). Total movements and ambulations are reported. Ambulations represent movements characterized by a relocation of the entire body position like walking, whereas total movements represent all movements made by the animals, including ambulations but also smaller or more fine movements like grooming, weaving or movements of the head. During motor activity monitoring, all animals were caged individually (pups were housed in their home cages and kept warm using bottles filled with warm water). The selected males were tested during Week 4 of treatment and the selected females were tested towards the end of the scheduled lactation period (all before blood sampling). These tests were performed as soon as possible after observation for clinical signs (incl. arena observation, if applicable), and before blood sampling.

POSTMORTEM EXAMINATIONS:
- Necropsy: All males, the selected females/group 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: Lactation Days 5-7, Females which failed to deliver: Post-coitum Day 25-26 (females with evidence of mating). Spontaneous deaths: as soon as possible after death and always within 24 hours. 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. The numbers of former implantation sites and corpora lutea were recorded for all paired females (for females which failed to deliver: In case no macroscopically visible implantation sites were present, nongravid uteri were stained using the Salewski technique in order to detect any former implantation sites).

Samples of the following tissues and organs were collected from all animals and fixed in 10% buffered formalin (neutral phosphate buffered 4% formaldehyde solution, Klinipath, Duiven, The Netherlands): Adrenal glands, (Aorta), Brain - cerebellum, mid-brain, cortex, Caecum, Cervix, Clitoral gland, Colon, Coagulation gland, Duodenum, Epididymides, Eyes (with optic nerve (if detectable) and Harderian gland), (Male and Female mammary gland area), Femur including joint, Heart, Ileum, Jejunum, Kidneys, (Lacrimal gland, exorbital), (Larynx), Liver, Lung, infused with formalin, Lymph nodes - mandibular, mesenteric, (Nasopharynx), (Esophagus), Ovaries, (Pancreas), Peyer's patches [jejunum, ileum] if detectable, Pituitary gland, Preputial gland, Prostate gland, Rectum, (Salivary glands - mandibular, sublingual), Sciatic nerve, Seminal vesicles, Skeletal muscle, (Skin), Spinal cord -cervical, midthoracic, lumbar, Spleen, Sternum with bone marrow, Stomach (forestomach and glandular stomach), Testes, Thymus, Thyroid including parathyroid if detectable, (Tongue), Trachea, Urinary bladder, Uterus, Vagina, All gross lesions. The epididymides, eyes and testes were fixed in modified Davidson's solution and Milli-Ro water and transferred to formalin after fixation for at least 24 hours. Tissues/organs mentioned in parentheses were not examined by the pathologist, since no signs of toxicity were noted at macroscopic examination.

- Organ weights: The following organ weights and terminal body weight were recorded from the selected 5 animals/sex/group on the scheduled day of necropsy: Adrenal glands, Brain, Epididymides, Heart, Kidneys, Liver, Ovaries, Spleen, Testes, Thymus, Uterus (including cervix), Prostate (weighed when fixed for at least 24 hours), Seminal vesicles including coagulating glands (weighed when fixed for at least 24 hours), Thyroid including parathyroid (weighed when fixed for at least 24 hours). All remaining males: Epididymides, Testes.

- Histotechnology: All organ and tissue samples, as defined under Histopathology (following section), were processed, embedded and cut at a thickness of 2-4 micrometers and stained with haematoxylin and eosin (Klinipath, Duiven, The Netherlands).

- Histopathology: The following slides were examined by a pathologist: (1) The preserved organs and tissues of the selected 5 animals/sex of Groups 1 and 4. (2) 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. (3) All gross lesions of all animals (all dose groups). (4) The preserved organs and tissues of the animals of the two Group 4 females that either died spontaneously or were euthanized due to a total litter loss. (5) The spleen and thymus of all selected 5 females of Groups 2 and 3, based on (possible) treatment-related changes in these organs in Group 4. (6) The reproductive organs (cervix, clitoral gland, coagulation gland, epididymides, ovaries, preputial gland, prostate gland, seminal vesicles, testes, uterus, and vagina) of male no. 31 (Group 4) and female no. 71 (Group 4) that had a total litter loss.

Fetal examinations:

LITTER OBSERVATIONS:
- Mortality / Viability: The numbers of live and dead pups on Day 1 of lactation and daily thereafter were determined. If possible, defects or cause of death were evaluated.
- Clinical signs: At least once daily, detailed clinical observations were made for all animals.
- Body weights: Live pups were weighed on Days 1 and 4 of lactation.
- Sex: Sex was determined for all pups on Days 1 and 4 of lactation.

POSTMORTEM OBSERVATIONS
Pups surviving to planned termination were killed by decapitation on Days 5-7 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 (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 if the data could not be assumed to follow a normal distribution.
- The Fisher Exact-test was applied to frequency data.
- 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.

Indices:

For each group, the following calculations were performed:
- Mating index (%) = (Number of females mated / Number of females paired) x 100
- Fertility index (%) = (Number of pregnant females / Number of females paired) x 100
- Conception index (%) = (Number of pregnant females / Number of females mated) x 100
- Gestation index (%) = (Number of females bearing live pups / Number of pregnant females) x 100
- Duration of gestation = Number of days between confirmation of mating and the beginning of parturition
- Percentage live males at First Litter Check = (Number of live male pups at First Litter Check / Number of live pups at First Litter Check) x 100
- Percentage live females at First Litter Check = (Number of live female pups at First Litter Check / Number of live pups at First Litter Check) x 100
- Percentage of postnatal loss Days 0-4 of lactation = (Number of dead pups on Day 4 of lactation / Number of live pups at First Litter Check) x 100
- Viability index = (Number of live pups on Day 4 post partum / Number of pups born alive) x 100

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

For females at 150 mg/kg bw/day hunched posture, piloerection and pale faeces were noted mainly during the last two weeks of treatment. No clinical signs of toxicity were noted for females at 15 and 45 mg/kg bw/day and males up to 150 mg/kg bw/day. Salivation seen after dosing among females of the 150 mg/kg bw/day dose group towards the end of the treatment period 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 irritancy/taste of the test substance.
Incidental findings that were noted for a single female each at 15, 45 and 150 mg/kg bw/day included hunched posture, salivation and purple discolouration of the ear, respectively. In addition, scabbing was recorded for two males at 150 mg/kg bw/day. These findings occurred within the range of background findings to be expected for rats of this age and strain which are housed and treated under the conditions in this study. At the low incidence observed, these were considered signs of no toxicological relevance.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No mortalities occurred that were considered to be a direct cause of treatment with Irgamet 39 up to 150 mg/kg bw/day.
One female at 150 mg/kg bw/day died during parturition on Day 21 post-coitum (ten healthy pups were already delivered). No clinical signs were noted. Food consumption (absolute and relative to body weight) was only slightly lower from Days 14-20 post-coitum with no effects on body weight. At necropsy, three fully developed fetuses were discovered in the right uterus horn and watery cloudy fluid was found in the lungs which correlated with the finding of alveolar proteinaceous fluid at the microscopic level. These necropsy findings were indicative for parturition difficulties that likely resulted in circulatory failure. In addition, her spleen was reduced in size and many dark red foci were noted on the thymus.
Another female at 150 mg/kg bw/day had to be euthanized due to a total litter loss on Day 2 of lactation. Clinical signs were recorded from the end of the post-coitum phase onwards and consisted of hunched posture, piloerection and pale faeces. This female had the lowest body weight and the lowest food consumption in this group. At necropsy, the only finding was a smaller thymus. No mortality occurred at the lower doses of 45 and 15 mg/kg bw/day or in the control group.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

There was a trend towards lower body weights as compared to controls for males and females at 150 mg/kg bw/day during the post-coitum phase, reaching statistical significance in females on Day 20 post-coitum and during the subsequent phase of lactation as well as in males at termination. Body weight gains were significantly lower in females from Days 4-20 post-coitum. Body weight gain between Day 0 and 20 post-coitum was 74 g versus 104 g in controls. No toxicologically relevant changes in body weights and body weight gain were noted up to 45 mg/kg bw/day.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A lower food consumption (absolute and relative to body weight) was recorded for females at 150 mg/kg bw/day as compared to controls during the entire treatment period, though differences were not always statistically significant. For females up to 45 mg/kg bw/day and males up to 150 mg/kg bw/day, food consumption was in the same range as for control animals. For one cage with five males (cage no. 7; male nos. 31-35) at 150 mg/kg bw/day food consumption (absolute and relative to body weight) was slightly lower during the first week of treatment. However, changes were only slight and transient, and no comparable effect was noted for the other cage with high dose males. Therefore, this finding was not considered to be toxicologically relevant.

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):

Haematological parameters of treated rats were considered not to have been affected by treatment up to 150 mg/kg bw/day. Any statistically significant changes observed were considered to be of no toxicological relevance as no treatment-related distribution could be established, changes occurred in the absence of corroborating effects in related parameters and remained within the range considered normal for rats of this age and strain. These changes included a decreased prothrombin time (PT) for males at 150 mg/kg bw/day and increased values for white blood cell count (WBC), mean corpuscular haemoglobin concentration (MCHC) and activated partial prothrombin time (APTT) for females at 45 and/or 150 mg/kg bw/day.

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 up to 150 mg/kg bw/day. Any statistically significant changes observed were considered to be of no toxicological relevance as no treatment-related distribution could be established, changes occurred in the absence of corroborating effects in related parameters, remained within the range considered normal for rats of this age and strain and/or were the result of relatively low control values. These changes included increased concentrations of potassium for males at 45 mg/kg bw/day and increased concentrations of creatinine, bile acids and inorganic phosphates for females at 15, 45 and/or 150 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 selected animals. The variation in motor activity did not indicate a relation with treatment. All groups showed a similar habituation profile with very high activity in the first interval that decreased over the duration of the test period. For males, there was a trend towards lower total movements with increasing dose (not statistically significant). However, all values remained within the normal range of biological variation. Moreover, there were no corroborative findings during clinical observations and no comparable change was seen for females. Therefore, this finding was considered to be a chance finding rather than a sign of toxicity.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

For females at 150 mg/kg bw/day, mean thymus organ weight (absolute and relative to body weight) was at the lower end of the historical range (0.131 gram and 0.062% versus a P5 of 0.129 gram and 0.0578%), though no statistical significance was reached as compared to controls. This difference was particularly due to animals no. 73, 76 and 78. The increased brain to body weight ratio recorded for males at 150 mg/kg bw/day was secondary to the lower terminal body weights and was not considered to be toxicologically relevant. The increased thyroid organ weight (absolute and relative to body weight) recorded for males at 45 mg/kg bw/day as compared to controls was considered not to be a sign of toxicity as no treatmentrelated distribution could be established. Statistical significance is rather due to the relatively low control value. Other organ weights and organ to body weight ratios among the dose groups were similar to control levels.

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no treatment-related necropsy findings. The incidence of other incidental findings among control and treated animals was within the background range of findings that are encountered among rats of this age and strain, and did not show a dose-related incidence trend. These necropsy findings were therefore considered to be of no toxicological relevance. They included pelvic dilation of one or both kidneys, isolated or several reddish foci on the glandular mucosa of the stomach, reddish or dark-red discolouration of mandibular lymph nodes or thymus, yellowish soft nodule on the tail of the epididymides, an isolated tan or greenish focus on the clitoral glands, dark-red content of the vagina (revealed as parturition debris at the microscopic level), fluid-filled uterus, and scabbing.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

There were treatment-related microscopic findings in the thymus and spleen of females.
Thymus: Lymphoid atrophy (involution) was present in 4/7 (2 minimal, 1 slight, 1 moderate) females treated at 150 mg/kg bw/day, and did correlate with low thymus weights in females 73, 76 and 78.

Spleen: A decreased severity of hemopoietic foci, primarily erythropoiesis was present in 6/6 (4 minimal, 1 slight, 1 moderate) females treated at 150 mg/kg bw/day compared to normal levels in 5/5 control (1 minimal, 1 slight, 2 moderate, 1 marked), 5/5 15 mg/kg bw/day (2 slight, 1 moderate, 2 marked) and 5/5 45 mg/kg bw/day (1 minimal, 3 moderate, 1 marked) treated female rats.

All other microscopic findings recorded were considered to be within the normal range of background pathology encountered in Wistar-Han rats of this age.
There were two Group 3 and four Group 4 rats that failed to mate, conceive, sire or deliver healthy offspring and were therefore selected for histopathological examination of the reproductive organs. No cause of infertility was found for these animals.
The total litter loss observed for one female of group 4 (150 mg/kg bw/day) could not be explained based on the microscopic examination. There was proteinaceous fluid (milk) present in the mammary gland of this female.

The assessment of the integrity of the spermatogenetic cycle did not provide any evidence of impaired spermatogenesis.
There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item.

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Description (incidence and severity):

REPRODUCTION DATA
No toxicologically relevant effects on reproductive parameters were noted.
Mating, fertility and conception indices, precoital time, and number of corpora lutea and implantation sites were considered to be unaffected by treatment.
All females were mated within four days. However, one female at 45 and 150 mg/kg bw/day each appeared to be not pregnant. In the absence of any morphological findings in the reproductive organs of these two females and her male partners which could be attributed to the test item, it was considered a chance finding rather than a treatment related effect.
A trend towards a slightly lower mean number of implantation sites was noted at 150 mg/kg bw/day (not statistically relevant). One female (78) had 18 corpora lutea but carried only 6 implantations. This finding was not considered to be toxicologically relevant as it was an isolated observation and all other females of the high dose group carried 10-14 implantation sites which was within the normal range of biological variation.

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

A trend towards a slightly lower mean number of implantation sites was noted at 150 mg/kg bw/day (not statistically relevant). One female (78) had 18 corpora lutea but carried only 6 implantations. This finding was not considered to be toxicologically relevant as it was an isolated observation and all other females of the high dose group carried 10-14 implantation sites which was within the normal range of biological variation.

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

not examined

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not examined

Changes in number of pregnant:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

GESTATION
The gestation index and duration of gestation were unaffected up to 150 mg/kg bw/day. The gestation index was 100% for females of the control, 15 and 45 mg/kg bw/day groups. The slightly lower gestation index of 88.9 % for the 150 mg/kg bw/day group was caused by the fact that one female died during littering. This finding was not considered to be a direct cause of treatment with the test article.

PARTURITION / MATERNAL CARE
Parturition and subsequent maternal care were considered to be unaffected by treatment up to 150 mg/kg bw/day. One female at 150 mg/kg bw/day died after she had delivered ten healthy pups. At necropsy, three fully developed fetuses were found in the right uterus horn at necropsy. Furthermore, watery cloudy fluid was noted in the lungs which correlated with the finding of alveolar proteinaceous fluid at the microscopic level. These findings were indicative for severe parturition difficulties that resulted in circulatory failure. As no signs of difficult or prolonged parturition were noted for the remaining pregnant females in this group and complications during parturition are incidentally seen in this type of study, the sudden death of the single high dose female was considered not to be treatment related. Examination of cage debris of pregnant females revealed no signs of abortion or premature birth. For one female (71) at 150 mg/kg bw/day it was not clear if deficiencies in maternal care had occurred, as none of her pups that was alive at first litter check had milk in the stomach and a total litter loss was recorded on lactation Day 2. However, proteinaceous fluid (milk) was present her mammary glands. It should be noted that during the post-coitum phase lower body weights and food consumption were recorded for this female as compared to the remaining high dose females. This may indicate that this female was in a poor condition.

Key result

Dose descriptor:

NOAEL

Effect level:

45 mg/kg bw (total dose)

Basis for effect level:

body weight and weight gain

clinical signs

food consumption and compound intake

histopathology: non-neoplastic

organ weights and organ / body weight ratios

Key result

Dose descriptor:

NOAEL

Effect level:

45 mg/kg bw (total dose)

Based on:

test mat.

Basis for effect level:

total litter losses by resorption

Key result

Abnormalities:

no effects observed

Fetal body weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Mean pup body weights were in general lower in litters of the 150 mg/kg bw/day group as compared to control litters, except for pups in litters 77 and 78. This difference was attributed to the relatively low size of the latter litters (5-6 pups versus 10-12 pups). The lower pup body weights were likely secondary to the lower body weight gain recorded for their dams as compared to controls during the post-coitum and lactation period. In line with this is the fact that the treated pups gained a comparable percentage of weight as controls from postnatal Days 1-4 (48 versus 51% gain for pups from the 150 mg/kg bw/day and control groups, respectively). As such, the differences in pup body weights at 150 mg/kg bw/day were not considered to be toxicologically relevant.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not examined

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

The number of dead pups at first litter check was unaffected by treatment up to 150 mg/kg bw/day. Postnatal loss was significantly higher at 150 mg/kg bw/day. The number of pups that were found dead or missing during the first days of lactation were 1, 0, 2 and 11, respectively, in the control, 15, 45 and 150 mg/kg bw/day groups. From the eleven pups in the high dose group, eight came from the single dam who had a total litter loss. The last three pups were distributed over three litters. In addition, a litter of ten pups had to be euthanized because their mother had died spontaneously. Hence, their death was not directly related to treatment. Due to the relatively high post natal loss the viability index for the 150 mg/kg bw/day group reached only 84.9% as compared to 99.1%, 100.0% and 98.3% for the control, 15 and 45 mg/kg bw/day groups, respectively.

Changes in sex ratio:

no effects observed

Description (incidence and severity):

The sex ratio was unaffected by treatment.

Changes in litter size and weights:

effects observed, treatment-related

Description (incidence and severity):

There were significantly fewer living pups at first litter check at 150 mg/kg bw/day. Mean litter sizes were 11.6, 11.4, 12.9 and 9.1 pups for the control, 15, 45 and 150 mg/kg bw/day groups, respectively. In total, only 73 pups (8 litters) were born in the 150 mg/kg bw/day group as compared to 116 (10 litters), 114 (10 litters) and 116 pups (9 litters) in the control, 15 and 45 mg/kg bw/day groups. This number does not include the 10 pups from the dam at 150 mg/kg bw/day that died during littering. A compound-related effect cannot be ruled out. However, the low number of animals (8) precludes a final assessment.

Changes in postnatal survival:

not examined

External malformations:

no effects observed

Description (incidence and severity):

For one pup at 45 mg/kg bw/day that was found dead on Day 5 of lactation beginning autolysis and absence of milk in the stomach were noted. One control pup that survived until planned necropsy had a lean appearance. The nature and incidence of these findings remained within the range considered normal for pups of this age, and were therefore considered to be of no toxicological relevance. No milk in the stomach was noted at macroscopic examination for all pups from litters 41, 47, 52, 60, 61, 62, 66, 67, 74, 77 and 78. This was not considered to be treatment related or toxicologically relevant since no treatment-related distribution could be established. Moreover, pups from these litters survived until scheduled necropsy, indicating they were all sufficiently fed during the first days of lactation. Therefore, this finding was likely secondary to the time when the actual necropsies were performed. For all these litters it was not attributable to treatment.

Skeletal malformations:

not examined

Visceral malformations:

not examined

Other effects:

no effects observed

Description (incidence and severity):

Clinical signs
At first litter check, absence of milk in the stomach was noted for all alive pups of one litter (71) at 150 mg/kg bw/day. On the next morning, these pups were either found dead or missing. No abnormalities were noted for these dead pups. Pale or lean appearance were recorded for two single pups. The nature and incidence of these clinical signs remained within the range considered normal for pups of this age, and were therefore considered to be of no toxicological relevance.

Key result

Dose descriptor:

NOAEL

Effect level:

45 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

changes in litter size and weights

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

150 mg/kg bw/day (nominal)

Treatment related:

yes

Relation to maternal toxicity:

developmental effects as a secondary non-specific consequence of maternal toxicity effects

Dose response relationship:

yes

Formulation analyses revealed that the high concentration was prepared accurately. The low and mid concentrations were slightly higher than nominal (119% and 116%, respectively). The mid and high concentrations were homogeneously (i.e. coefficient of variation ≤ 10%), whereas the low concentration was not homogeneous (i.e. coefficient of variation of 20.9%). No test compound was detected in the vehicle formulation. The inhomogeneity of the formulation for Group 2 (15 mg/kg bw/day) had no impact on the outcome of this study as the No Observed Adverse Effect Levels (NOAEL) derived were at 45 or 150 mg/kg bw/day (see further below). Formulations at the entire range were stable when stored at room temperature under normal laboratory light conditions for at least 5 hours (i.e. relative difference ≤ 10%).

Conclusions:

Based on the results presented, the following No Observed Adverse Effect Levels (NOAEL) were derived:
Parental NOAEL: 45 mg/kg bw/day; Developmental NOAEL: 45 mg/kg bw/day

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 15, 45 and 150 mg/kg bw/day. Animals of the control group received the vehicle, 0.5% carboxymethyl cellulose and 0.1% Tween-80 in water, alone. Males were exposed for 29 days, i.e. 2 weeks prior to mating, during mating, and up to termination. Females were exposed for 42-45 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 (Week 4 (males); end of lactation (females)), body weight and food consumption (at least at weekly intervals), clinical pathology (Week 4 (males); end of lactation (females)), 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.

Toxicity was noted at 150 mg/kg bw/day. For females, it was characterized by clinical signs, reduced body weight gains with lower food consumption, and slightly reduced thymus organ weight. The slightly lower thymus organ weights were in line with the observation of lymphoid atrophy (involution) present in 4 out of the 7 examined females in this high dose group (2 minimal, 1 slight, 1 moderate). Further microscopic findings consisted of lower mean grade of hematopoietic foci in the spleen of females at 150 mg/kg bw/day. Slightly lower body weight gains were also observed for males at 150 mg/kg bw/day.

No toxicologically significant changes were noted in any of the remaining parental parameters investigated in this study (i.e. mortality, functional observations, haematology, clinical biochemistry, macroscopic abnormalities).

There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item. No reproduction toxicity was observed up to the highest dose level tested (150 mg/kg bw/day).

Smaller mean litter size at first litter check was noted at 150 mg/kg. A compound-related effect cannot be ruled out. However, the low number of animals (n=8) precludes a final assessment. The lower pup body weights at 150 mg/kg bw/day were considered secondary to the reduced body weights of their dams. No toxicologically significant changes were noted in any of the remaining developmental parameters investigated in this study (i.e. duration of gestation, parturition and macroscopy). Pup development was unaffected by treatment at 15 or 45 mg/kg bw/day.

In conclusion, treatment with test material by oral gavage in male and female Wistar Han rats at dose levels of 15, 45 or 150 mg/kg bw/day revealed parental toxicity at 150 mg/kg bw/day. No reproduction toxicity was observed for treatment up to 150 mg/kg bw/day. Developmental toxicity occurred at 150 mg/kg bw/day. Based on these results, the following No Observed Adverse Effect Levels (NOAEL) were derived:

Parental NOAEL: 45 mg/kg bw/day;

Reproduction NOAEL: 150 mg/kg bw/day;

Developmental NOAEL: 45 mg/kg bw/day.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

45 mg/kg bw/day

Study duration:

subchronic

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

Quality of whole database:

GLP and guideline complian study.

Additional information

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 15, 45 and 150 mg/kg bw/day by oral gavage. Animals of the control group received the vehicle alone. Males were exposed for 2 weeks prior to mating, during mating, and up to termination (for 29 days). The females were exposed for 2 weeks prior to mating, during mating, during post-coitum, and at least 4 days of lactation (for 42-45 days).

Toxicity was noted at 150 mg/kg bw/day. For females, it was characterized by clinical signs, reduced body weight gains with lower food consumption, and slightly reduced thymus organ weight. The slightly lower thymus organ weights were in line with the observation of lymphoid atrophy (involution) present in 4 out of the 7 examined females in this high dose group (2 minimal, 1 slight, 1 moderate). Further microscopic findings consisted of lower mean grade of hematopoietic foci in the spleen of females at 150 mg/kg bw/day. Slightly lower body weight gains were also observed for males at 150 mg/kg bw/day. No toxicologically significant changes were noted in any of the remaining parental parameters investigated in this study (i.e. mortality, functional observations, haematology, clinical biochemistry, macroscopic abnormalities). There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item. No reproduction toxicity was observed up to the highest dose level tested (150 mg/kg bw/day). Smaller mean litter size at first litter check was noted at 150 mg/kg. A compound-related effect cannot be ruled out. However, the low number of animals (n=8) precludes a final assessment. The lower pup body weights at 150 mg/kg bw/day were considered secondary to the reduced body weights of their dams. No toxicologically significant changes were noted in any of the remaining developmental parameters investigated in this study (i.e. duration of gestation, parturition and macroscopy). Pup development was unaffected by treatment at 15 or 45 mg/kg bw/day. In conclusion, treatment with test material by oral gavage in male and female Wistar Han rats at dose levels of 15, 45 or 150 mg/kg bw/day revealed parental toxicity at 150 mg/kg bw/day. Based on these results, the following No Observed Adverse Effect Levels (NOAEL) were derived:

Parental NOAEL: 45 mg/kg bw/day;

Reproduction NOAEL: 150 mg/kg bw/day;

Developmental NOAEL: 45 mg/kg bw/day.

Recent hydrolysis data suggest that the test article rapidly hydrolyses to formaldehyde (CAS No. 50-00-0), bis(2-ethylhexyl)amine (CAS No. 106-20-7) and tolyltriazole (CAS No. 29385-43-1), none of which is classified for reproduction and developmental toxicity. Therefore, based on the data available for the test article and taking the data from the proposed hydrolysis products into account, the test article is not considered toxic to development.

Justification for classification or non-classification

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

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. Considering the data available and hydrolysis products the substance is not considered to be classified for toxicity to reproduction under Regulation (EC) No 1272/2008, as amended for the eighth time in Regulation (EU) No 2016/218.