Registration Dossier

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

The potential of DBU to cause reproductive or developmental toxicity was assessed in a modern GLP- and guideline-compliant screening study [OECD422] (BASF, 2012).

Based on these results of this study, the NOAEL for parental toxicity is considered to be 50 mg/kg bw/d; the NOAEL for reproductive and developmental toxicity is 150 mg/kg bw/d (the highest dose tested).

Link to relevant study records
Reference
Endpoint:
screening for reproductive / developmental toxicity
Remarks:
based on test type (migrated information)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21st December 2011 to 20th August 2012.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted according to GLP and relevant testing guidelines.
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
not specified
Qualifier:
according to
Guideline:
other: EPA OPPTS 870.3650, Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test
Deviations:
not specified
Qualifier:
according to
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
Deviations:
not specified
Qualifier:
equivalent or similar to
Guideline:
other: EPA OPPTS 870.3550, Reproduction/Developmental Toxicity Screening Test
Deviations:
not specified
GLP compliance:
yes
Limit test:
no
Species:
rat
Strain:
other: Crl:WI(Han)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Approximately 11 weeks.
- Housing: Pre-mating animals were housed in groups of 5 animals/sex/cage in Macrolon plastic cages (MIV type, height 18 cm). During 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). During 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. During locomotor activity monitoring, animals were housed individually in a Hi-temp polycarbonate cage (48.3 x 26.7 x 20.3 cm).
- Diet (e.g. ad libitum): Free access to pelleted rodent diet
- Water (e.g. ad libitum): Free access to tap-water.
- Acclimation period: At least 5 days prior to start of treatment.

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

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
Formulations (w/w) were prepared daily within 30 minutes prior to dosing and were homogenized to a visually acceptable level. Adjustment was made for the density of the test substance.
On the first day of dosing, the pH value of Groups 2-4 formulations were determined. Based on information that the test substance may react with glass, the formulations were prepared in plastic vials.
Formulations were placed on a magnetic stirrer during dosing.

VEHICLE
Water
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:
Analyses were conducted on a single occasion during the treatment phase. Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations). Stability in vehicle over 30 minutes at room temperature was also determined (highest and lowest concentration). The accuracy of preparation was considered acceptable if the mean measured concentrations were 90-110% 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.
Females were exposed for 43 to 57 days
Frequency of treatment:
Once daily, seven days per week.
Details on study schedule:
Not applicable.
Remarks:
Doses / Concentrations:
0, 15, 50, 150 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
5 animals per sex per dose group.
Control animals:
not specified
Details on study design:
- Dose selection rationale:
The doses selected for this study are based on results from a 14-day dose range finding study where the doses were administered were 0, 15, 40, 100 and 200 mg/kg bw/day. At 200 mg/kg bw/day, slight body weight loss or reduced gains were seen along with changes in clinical pathology parameters. Reddish foci on the stomach glandular mucosa were seen for all animals at this dose level during the macroscopic examination. Therefore, 200 mg/kg was considered to be in excess of the MTD for the main study. No adverse effects were noted at 100 mg/kg bw/day. Based on these data, 15, 50 and 150 mg/kg bw/day were chosen for the main study.

-Rationale for animal assignment:
Prior to commencement of treatment, by computer-generated random algorithm according to body weight, with all animals within ± 20% of the sex mean.
Positive control:
No data.
Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Mortality/viability were examined at least twice daily.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At least once daily from start of treatment onwards, detailed clinical observations were conducted for all animals. Once prior to start of treatment and at weekly intervals during the treatment period this was also performed outside the home cage in a standard arena.

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

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
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 (if drinking water study):
Subjective appraisal was maintained during the study, but no quantitative investigation was introduced as no treatment related effect was suspected.

OTHER:
HAEMATOLOGY: Yes
- Time schedule for collection of blood: Prior to scheduled post-mortem examination.
- Anaesthetic used for blood collection: Yes, isoflurane.
- Animals fasted: Yes, for a maximum of 20 hours.
- How many animals: 5 animals per sex per group.
- Parameters checked: White blood cells (WBC) and Differential leucocyte count, including Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils, Red blood cells, Reticulocytes, Red blood cell distribution width (RDW), Haemoglobin, Haematocrit, Mean corpuscular volume (MCV), Mean corpuscular haemoglobin (MCH), Mean corpuscular haemoglobin concentration (MCHC) and Platelets.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Prior to scheduled post-mortem examination.
- Animals fasted: Yes, for a maximum of 20 hours.
- How many animals: 5 animals per sex per group.
- Parameters checked: Alanine aminotransferase (ALAT), Aspartate aminotransferase (ASAT), Alkaline Phosphatase (ALP), Total protein, Albumin, Total Bilirubin, Bile acids, Urea, Creatinine, Glucose, Cholesterol, Sodium, Potassium, Chloride, Calcium and Inorganic Phosphate (Inorg. Phos).

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: The selected males were tested during Week 4 of treatment and the selected females were tested towards the end of the scheduled lactation period (all before blood sampling).
- Battery of functions tested: hearing ability, pupillary reflex, static righting reflex and grip strength.
Oestrous cyclicity (parental animals):
Male number paired with, mating date, confirmation of pregnancy, and delivery day were recorded. Pregnant females were examined to detect signs of difficult or prolonged parturition, and cage debris of pregnant females was examined to detect signs of abortion or premature birth. Any deficiencies in maternal care (such as inadequate construction or cleaning of the nest, pups left scattered and cold, physical abuse of pups or apparently inadequate lactation or feeding) were examined.
Sperm parameters (parental animals):
Parameters examined in [all/P/F1/F2] male parental generations:
Testes, epidymides.
Litter observations:
Each litter was examined to determine the mortality and viability, where the numbers of live and dead pups on Day 1 of lactation and daily thereafter were determined.
Detailled clinical observations were conducted at least once daily.
Body weights of live pups were measured on days 1 and 4 of lactation.
Sex was determined for all pups on days 1 and 4 of lactation.
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving animals were necropsied following completion of the mating period (a minimum of 28 days of dose administration).
- Maternal animals: Females who delivered were necropsied on lactation Days 5-7. Females who failed to deliver were necropsied post-coitum on days 25-28 (females with evidence of mating) or approximately 21 days after the last day of the mating period (females without evidence of mating).

GROSS NECROPSY
- 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.

HISTOPATHOLOGY / ORGAN WEIGHTS
Alanine aminotransferase (ALAT), Aspartate aminotransferase (ASAT), Alkaline Phosphatase (ALP), Total protein, Albumin, Total Bilirubin, Bile acids, Urea, Creatinine, Glucose, Cholesterol, Sodium, Potassium, Chloride, Calcium and Inorganic Phosphate (Inorg. Phos).
Postmortem examinations (offspring):
SACRIFICE
Pups surviving to planned termination were killed by decapitation between Days 5-7 of lactation.

GROSS NECROPSY
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.

HISTOPATHOLOGY / ORGAN WEIGTHS
Adrenal glands, Spleen, Brain, Testes, Epididymides, Thymus, Heart, Uterus (including cervix), Kidneys, Prostate, Liver, Seminal vesicles including coagulating glands, Ovaries and Thyroid including parathyroid.
Statistics:
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.
The following additional methods of statistical analysis were used:
Motor activity data was subjected to the Kruskal-Wallis nonparametric ANOVA test to determine intergroup differences followed by the Wilcoxon test to compare the treated groups to the control group.
All tests were two-sided and in all cases p < 0.05 was accepted as the lowest level of significance.
Group means were calculated for continuous data and medians were calculated for discrete data (scores) in the summary tables. Test statistics were calculated on the basis of exact values for means and pooled variances. Individual values, means and standard deviations may have been rounded off before printing. Therefore, two groups may display the same printed means for a given parameter, yet display different test statistics values.
Reproductive indices:
Mating Index, Fertility index, Conception index, Gestation index, Viability index.
Offspring viability indices:
Percentage live males at First Litter Check, Percentage live females at First Litter Check, percentage of postnatal loss Days 0-4 of lactation, viability index.
Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
: stomach histopathology at 150 mg/kg bw/d
Other effects:
not specified
Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
No mortality occurred during the study period. No toxicologically significant clinical signs were noted up to 150 mg/kg bw/d. At 150 mg/kg bw/d, salivation was noted for six males and four females over a few days towards the end of the treatment period. This may be related to the taste of the test substance, and was considered to be a physiological response rather than a sign of systemic toxicity. Hunched posture and rales were also noted for a few animals on a few occasions. As inflammatory changes were observed in the stomach for animals at this dose level, it is possible these symptoms were indicative of discomfort due to local stomach effects of the test substance. Hunched posture and/or laboured respiration were noted for individual animals at 15 and 50 mg/kg bw/d over 1-3 days. Due to the transient nature and limited occurrence, these signs were not considered to be toxicologically relevant. Broken tail apex was an incidental finding noted for single males in the control and 50 mg/kg bw/d groups which had no relationship to treatment.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
No toxicologically relevant changes in body weights and body weight gain were noted up to 150 mg/kg bw/d. Individual animals at 150 mg/kg bw/d lost weight over a single time point during the mating and post coitum periods, respectively. Since this occurred for individual animals and was transient for the female, this was not considered to be indicative of systemic toxicity. Body weight gains were significantly lower for males at 50 mg/kg bw/d on Day 8 of the pre-mating period. As the difference from controls was only slight and occurred in the absence of a dose response, it was not considered to be toxicologically relevant.
REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
No toxicologically relevant effects on reproductive parameters were noted. The mating, fertility and conception indices, precoital time, and numbers of corpora lutea and implantation sites were unaffected by treatment up to 150 mg/kg bw/d.
ORGAN WEIGHTS (PARENTAL ANIMALS)
Absolute and relative kidney weights were dose dependently higher for females of treated groups than controls, but only reached statistical significance at 150 mg/kg bw/d. The same relationship was not observed for males. However, in the absence of any effects on relevant clinical pathology parameters or treatment-related findings noted in the kidneys during the microscopic examination, the increased weights were not considered to be biologically relevant. There were no other effects on organ weights or organ to body weight ratios at any dose level tested.
GROSS PATHOLOGY (PARENTAL ANIMALS)
Dark red foci on the stomach glandular mucosa were noted for 5 males at 150 mg/kg bw/d. In addition, irregular surface and dark red discoloration of the glandular mucosa were noted for a single female and dark red discoloration of the mesenteric lymph node was noted for a single male at this dose level. An isolated, reddish focus on the stomach glandular mucosa was also seen for a single control male, however, due to the increased incidence, the foci seen for males at 150 mg/kg bw/d were considered to be treatment related. Incidental findings noted for control and/or treated animals included a bent tail, reddish or dark red foci on the thymus, pelvic dilation of the kidneys, dark red foci on the lungs, a tan focus or greenish discoloration of the clitoral gland, and alopecia on the foreleg. These findings did not show a dose related trend and were not considered to be toxicologically relevant. One female at 50 mg/kg bw/d was found with two mummified fetuses in the cervix at the macroscopic examination. As there were no developmental or reproductive findings noted at any dose level, this was not considered to be treatment related.
HISTOPATHOLOGY (PARENTAL ANIMALS)
Findings attributed to the test article were limited to the stomach and spleen, mostly for animals at 150 mg/kg bw/d.
Stomach:
Most stomach observations were confined to animals given 150 mg/kg bw/d.
-Minimal to moderate hemorrhage was observed 0/6, 1/5, 1/5, and 7/8 males in the respective 0, 15, 50 and 150 mg/kg bw/d dose groups. Minimal or slight hemorrhage was present in the glandular mucosa of 1/5 15 mg/kg bw/d and 2/5 150 mg/kg bw/d females.
-Moderate degeneration of the glandular mucosa was present in 1/8 150 mg/kg bw/d males. Minimal degeneration was present in the glandular mucosa of 1/5 150 mg/kg bw/d females.
-Minimal or slight inflammation was present in 7/8 males and 1/5 females at 150 mg/kg bw/d.
-Minimal or slight hyperplasia of non-glandular epithelium was present in 4/8 males and 2/5 females at 150 mg/kg bw/d.
-Minimal hyperkeratosis was observed in 3/8 males and 2/5 females at 150 mg/kg bw/d.
Spleen:
The average severity grades of splenic hematopoiesis were 2.0, 2.4, 1.8 and 1.2 in the respective 0, 15, 50 and 150 mg/kg bw/d dose groups for males. Females at 150 mg/kg bw/d were comparable to controls. In consideration that female 150 mg/kg bw/d animals were comparable to controls and that any significant blood loss from the stomachs of 150 mg/kg bw/d males should have resulted in increased levels of normally occurring hematopoiesis, the decrease in average severity may be spurious.
No test article related abnormalities were seen in the reproductive organs.
There were 3/10 150 mg/kg bw/d males with seminiferous tubular degeneration, however, all were unilateral. One was centrally located slight and focal. The other two were focal, minimal (barely noticeable), and consisted of a single centrally located cross sectional tubule (comprised of sertoliform cells as are often seen in association with the rete). The testes from these two animals were essentially normal. PAS stains demonstrated the presence of all sperm development stages in all control and 150 mg/kg bw/d males. Degeneration was not attributed to the test article.

OTHER FINDINGS (PARENTAL ANIMALS)
HAEMATOLOGY
There were no toxicologically relevant effects on haematology parameters up to 150 mg/kg bw/d. Activated partial prothrombin time (APTT) was increased for females at 150 mg/kg bw/d. However, this was attributable to relatively high values obtained for 2 females, and in the absence of corroborating effects seen in any other parameters, this was not considered to be toxicologically relevant. Minor statistically significant differences seen between controls and animals receiving 15 and 50 mg/kg bw/d occurred in the absence of a dose response and were not considered to be biologically relevant.
CLINICAL CHEMISTRY
There were no toxicologically relevant effects on clinical biochemistry parameters up to 150 mg/kg bw/d. At 150 mg/kg bw/d, cholesterol was higher for males, though in the absence of any relevant effects on the liver seen for any other parameter, this was ultimately not considered to be toxicologically relevant. There was a slight trend toward lower glucose for animals of all treatment groups, though the difference from controls was not statistically significant and was not considered toxicologically relevant. Calcium was significantly lower for females at 50 mg/kg bw/d, but was not considered to be toxicologically relevant since the difference from controls was only slight and occurred in the absence of a treatment related distribution.

NEUROBEHAVIOUR
Hearing ability, pupillary reflex, static righting reflex and grip strength were normal in all animals. The variation in motor activity did not indicate a relation with treatment. Males at 15 mg/kg bw/d had significantly higher total movement and ambulatory counts. However, in the absence of a dose response and any relevant clinical signs noted like hyperactivity, the effects were not considered to be treatment related. All groups showed a similar habituation profile with very high activity in the first interval that decreased over the duration of the test period.
Dose descriptor:
NOAEL
Remarks:
parental toxicity
Effect level:
50 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: At 150mg/kg bw/day, parental effects on the stomach were observed at macroscopic and microscopic examination.
Dose descriptor:
NOAEL
Remarks:
reproductive toxicity
Effect level:
150 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No reproductive toxicity at the highest dose level of 150 mg/kg bw/d.
Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Sexual maturation:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
no effects observed
Histopathological findings:
not specified
VIABILITY (OFFSPRING)
One pup of the control group and two, one and two pups of the 15, 50 and 150 mg/kg bw/day groups were found dead during the first days of lactation. No toxicological relevance was attributed to these dead/missing pups since the mortality incidence did not show a dose-related trend and remained within the range considered normal for pups of this age.

CLINICAL SIGNS (OFFSPRING)
There were no clinical signs noted for any pup.

BODY WEIGHT (OFFSPRING)
Body weights of pups were unaffected by treatment up to 150 mg/kg bw/day.

GROSS PATHOLOGY (OFFSPRING)
The only macroscopic finding noted was cannibalism (with all organs present), noted for a single pup that was dead at the first litter check at 50 mg/kg bw/day. This was not related to treatment with 1,8-Diazabicyclo-5,4,0-undecene-7.

Dose descriptor:
NOAEL
Remarks:
developmental toxicity
Generation:
F1
Effect level:
150 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No effects on developmental parameters were observed at the highest dose level tested.
Reproductive effects observed:
not specified

No toxicologically relevant effects on gestation index and duration, parturition, maternal care and early postnatal pup development (mortality, clinical signs, body weight and macroscopic examination) were observed. The gestation index and duration of gestation were unaffected up to 150 mg/kg bw/day. The gestation index was 100, 90, 100 and 100% for females in the control, 15, 50 and 150 mg/kg bw/day groups, respectively. No signs of difficult or prolonged parturition were noted among the pregnant females. Examination of cage debris of pregnant females did not reveal signs of abortion or premature birth and no deficiencies in maternal care were observed. The number of dead and living pups at first litter check, postnatal loss and viability index were unaffected by treatment, and clinical signs, body weight and external macroscopic examination did not reveal treatment-related findings. There was a (statistically) significantly lower ratio of male to female pups (compared to controls) seen at 50 mg/kg bw/d. This was attributable to a comparatively high ratio of male to female pups (63/37) seen for controls, therefore the difference at 50 mg/kg bw/d was not due to treatment. In teh absence of any effects of treatment, a reproductive NOAEL of 150 mg/kg bw/d is determined for this study.

Conclusions:
In conclusion, treatment with 1,8-Diazabicyclo-5,4,0-undecene-7 by oral gavage in male and female Wistar Han rats at dose levels of 15, 50 and 150 mg/kg bw/day revealed parental toxicity at 150 mg/kg bw/day. The effects were local and limited to the stomach, and may have been caused by the strong alkaline corrosivity of the test substance. No reproduction and developmental toxicity was observed for treatment up to 150 mg/kg body weight/day.
Based on the results of the present study, the No Observed Adverse Effect Level (NOAEL) for Parental toxicity was 50 mg/kg bw/day. The NOAEL for reproductive and developmental toxicity was 150 mg/kg bw/day.
Executive summary:

In this OECD -422 screening study, groups of rats were exposed to DBU via oral gavage at concentrations of 0 (vehicle controls), 15, 50 and 150 mg/kg bw/d. Males were exposed for 29 days (2 weeks prior to mating, during mating, and up to termination). Females were exposed for between 43 and 57 days (during 2 weeks prior to mating, during mating, gestation and during 4 days of lactation). he following observations and examinations were evaluated: mortality / viability, clinical signs (daily), functional observations and locomotor activity (males: Week 4, females: end of lactation), body weight and food consumption (at least at weekly intervals), clinical pathology (males: Week 4, females: end of lactation), macroscopy at termination, organ weights and histopathology on a selection of tissues, and reproduction/ developmental parameters, consisting of mating, fertility and conception indices, precoital time, number ofcorpora luteaand 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 during the study to assess accuracy, homogeneity and stability. At the highest dose level of 150 mg/kg bw/d, local effects on the stomach were seen at necropsy, including dark red foci and irregular mucosal surface. Histopathology revealed findings including haemorrhage and degeneration of the glandular mucosa, inflammation, hyperplasia and hyperkeratosis. All effects of treatmnet were local, limited to the stomach and attributable to the strong alkaline corrosivity of the test substance. No toxicologically significant changes were noted in any of the remaining parental parameters investigated in this study (i.e. clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination). No effects of treatment on the stomach were noted at 15 and 50 mg/kg bw/d. No reproduction or developmental toxicity was observed up to the highest dose level tested (150 mg/kg bw/d). Based on these results of this study, the NOAEL for parental toxicity is considered to be 50 mg/kg bw/d; the NOAEL for reproductive and developmental toxicity is 150 mg/kg bw/d (the highest dose tested).

Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
A modern OECD 422-compliant screening study is available for the submission substance.
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

The potential of DBU to cause reproductive or developmental toxicity was assessed in a modern GLP- and guideline-compliant screening study [OECD422] (BASF, 2012).

Groups of rats were exposed to DBU via oral gavage at concentrations of 0 (vehicle controls), 15, 50 and 150 mg/kg bw/d. Males were exposed for 29 days (2 weeks prior to mating, during mating, and up to termination). Females were exposed for between 43 and 57 days (during 2 weeks prior to mating, during mating, gestation and during 4 days of lactation). he following observations and examinations were evaluated: mortality / viability, clinical signs (daily), functional observations and locomotor activity (males: Week 4, females: end of lactation), body weight and food consumption (at least at weekly intervals), clinical pathology (males: Week 4, females: end of lactation), macroscopy at termination, organ weights and histopathology on a selection of tissues, and reproduction/ developmental parameters, consisting of mating, fertility and conception indices, precoital time, number of corpora lutea and implantation sites, gestation index and duration, parturition, maternal care, sex ratio and early postnatal pup development (mortality, clinical signs, body weights and macroscopy). Formulations were analyzed during the study to assess accuracy, homogeneity and stability. At the highest dose level of 150 mg/kg bw/d, local effects on the stomach were seen at necropsy, including dark red foci and irregular mucosal surface. Histopathology revealed findings including haemorrhage and degeneration of the glandular mucosa, inflammation, hyperplasia and hyperkeratosis. All effects of treatmnet were local, limited to the stomach and attributable to the strong alkaline corrosivity of the test substance. No toxicologically significant changes were noted in any of the remaining parental parameters investigated in this study (i.e. clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination). No effects of treatment on the stomach were noted at 15 and 50 mg/kg bw/d. No reproduction or developmental toxicity was observed up to the highest dose level tested (150 mg/kg bw/d). Based on these results of this study, the NOAEL for parental toxicity is considered to be 50 mg/kg bw/d; the NOAEL for reproductive and developmental toxicity is 150 mg/kg bw/d (the highest dose tested).


Effects on developmental toxicity

Description of key information
 The potential of DBU to cause developmental toxicity and/or teratogenicity was investigated in a modern GLP- and guideline-compliant OECD 414 study (BASF SE, 2017).
Link to relevant study records
Reference
Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes (incl. certificate)
Limit test:
no
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 11/0489-2
- Expiration date of the lot/batch: 17.12.2017
- Purity test date: 24.07.2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: ambient (room temperature)
- Stability under test conditions: The stability of the test substance under storage conditions over
the test period was guaranteed by the sponsor, and the sponsor
holds this responsibility. The test facility is organizationally
independent from the BASF SE sponsor division.
- Solubility and stability of the test substance in the solvent/vehicle:
Initially stability of 1,8-Diazabicyclo[5.4.0]undec-7-ene was proven over a period of 72 hours
at a concentration of 50 mg/100mL in drinking water (BASF SE 2017, Supplement). Due to
difficulties with the higher concentrations in preceding studies another stability analysis of 1,8-
Diazabicyclo[5.4.0]undec-7-ene at a concentration of 1200 mg/100mL in highly deionized
water was initiated before start of this study. Here the stability of 1,8-Diazabicyclo[5.4.0]undec-
7-ene in highly deionized water at room temperature over a period of 1.5 hours was proven
(BASF SE 2017, Supplement).

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: dilution in drinking water


OTHER SPECIFICS:
Physical state/appearance: liquid/colorless to yellow, clear
Batch identification: 43017568E0
Purity: >= 98 % (verified by Sponsor)
Content: 99.631 % (GC)
Homogeneity: given
Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services
GmbH, Sulzfeld, Germany
- Females (if applicable): pregnant: [yes]
- Age at study initiation: 10-12 weeks
- Weight at study initiation: Females: 141.8 – 189.9
- Fasting period before study: no
- Housing: The animals were housed together (5 animals per cage) in H-Temp polysulfonate cages type
2000P supplied by TECNIPLAST, Hohenpeißenberg, Germany (floor area about 2065 cm2).
- Diet (e.g. ad libitum): yes
- Water (e.g. ad libitum): yes
- Acclimation period: 6 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): room temperature: a range of temperature of 20-24°C
- Humidity (%): relative humidity of
30-70%
- Air changes (per hr): 15 air changes per hour
- Photoperiod (hrs dark / hrs light): The day/night cycle was 12 hours (12 hours light from
06.00-18.00 h, 12 hours dark from 18.00-06.00 h).

IN-LIFE DATES: From: To:

Males Females Phase of study/ Examination Study day
- Study initiation date: 02 Mar 2016
- Experimental starting date: (arrival of 1st cohort of test animals) 02 Mar 2016
- Supply of animals/ Beginning of acclimatization (GD 0): 1st cohort 02 Mar 2016 / 2nd cohort 03 Mar 2016
- Beginning of treatment/ End of acclimatization (GD 6): 1st cohort 08 Mar 2016 / 2nd cohort 09 Mar 2016
- End of treatment (GD 19): 1st cohort 21 Mar 2016 / 2nd cohort 22 Mar 2016
- Sacrifice of the animals (GD 20): 1st cohort 22 Mar 2016 / 2nd cohort 23 Mar 2016

Experimental completion date: (draft to QAU*) 03 May 2017
* QAU = Quality Assurance Unit
Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
VEHICLE
- Dose/Concentration/Volume in vehicle:
1. 0 [mg/kg BW/day] - 0 [g/100ml] - 10 [mL/kg]
2. 15 [mg/kg BW/day] - 0.15 [g/100ml] - 10 [mL/kg]
3. 50 [mg/kg BW/day] - 0.50 [g/100ml] - 10 [mL/kg]
4. 150 [mg/kg BW/day] - 1.50 [g/100ml] - 10 [mL/kg]
- Amount of vehicle (if gavage): please see above
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Analyses of the test substance preparations
The analyses of the test substance preparations were carried out at the Analytical Chemistry Laboratory of Experimental Toxicology and Ecology of BASF SE, Ludwigshafen, Germany. The stability of the test substance in drinking water at room temperature over a period of 72 hours had been verified prior to the start of the study (Project No.: 01Y0489/11Y177, see PART III). Furthermore, the stability of the test substance over 3 days in a concentration range covering the high-concentration used in this study (1500 mg/100 mL) was initiated during the study (Project No. 01Y0489/11Y179, see PART III). Samples of the test substance preparations were sent to the analytical laboratory twice during the study period (at the beginning and towards the end of administration) for verification of the concentrations. Given that the test substance was completely miscible with drinking water, solutions were considered homogenous without further analysis.
Details on mating procedure:
- Impregnation procedure: purchased timed pregnant

EXPERIMENTAL PROCEDURE
The animals were paired by the breeder (“time-mated”); the day of evidence of mating (= detection
of vaginal plug/sperm) was referred to as GD 0. The animals arrived on the same day
(GD 0) at the experimental laboratory. The following day was designated as “GD 1”.
The animals were acclimated to the laboratory conditions between start of the study (beginning
of the experimental phase) and first administration (GD 6).
Duration of treatment / exposure:
The test substance preparations were administered to the animals once a day orally by gavage,
from implantation to one day prior to the expected day of parturition (GD 6 to GD 19), always
at approximately the same time in the morning. The animals of the control groups were treated
with the vehicle (drinking water) in the same way. The volume administered each day was
10 ml/kg body weight. The calculation of the administration volume was based on the most
recent individual body weight.
Frequency of treatment:
The test substance preparations were administered to the animals once a day orally by gavage,
from implantation to one day prior to the expected day of parturition (GD 6 to GD 19), always
at approximately the same time in the morning.
Dose / conc.:
0 mg/kg bw/day (actual dose received)
Remarks:
control
Dose / conc.:
15 mg/kg bw/day (actual dose received)
Remarks:
low dose
Dose / conc.:
50 mg/kg bw/day (actual dose received)
Remarks:
mid dose
Dose / conc.:
150 mg/kg bw/day (actual dose received)
Remarks:
high dose
No. of animals per sex per dose:
25
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale:
Dose rational:
In an acute oral toxicity study (BASF Project No. 10A0064/901044), the LD (lethal dose) 50 of
1,8-Diazabicyclo-5,4,0-undecene-7 was found to be between 215 and 681 mg/kg bw/d.
A 14-day range-finding study (NOTOX Project 498334; BASF Project 01R0489/11X202) was
performed afterwards to select doses for an OECD 422 Combined Repeated Dose Toxicity
Study with the Reproduction/Developmental Toxicity Screening Test. Four groups of three
male and three female Wistar Han rats received the test substance by oral gavage at 0, 15, 40
and 100 mg/kg bw/d for 14 days. Since no in-life toxicity was seen at any dose level after the
14-day treatment period, group 2 animals (15 mg/kg bw/d) were retained for a second dosing
period of 14 days at 200 mg/kg bw/d. At 200 mg/kg bw/d, slight body weight loss and reduced
gains (- 3% from study day 0 to 14) were observed in females. Reddish foci on the stomach
glandular mucosa were seen for all animals during the macroscopic examination. No toxicologically
significant changes were noted in any of the remaining parental parameters investigated
in this study (i.e. clinical appearance, food consumption, clinical laboratory investigations,
macroscopic examination and organ weights).
Based on these results, the animals in the OECD 422 study (NOTOX Project 498331, BASF
Project 85R0489/11X203) received dose levels of 15, 50 and 150 mg/kg bw/d. At 150 mg/kg
bw/d, dark red foci and irregular surface of the stomach were seen at the macroscopic examination.
In histopathology, corroborative findings in the stomach, consisting of haemorrhage,
and degeneration of the glandular mucosa, inflammation, hyperplasia and hyperkeratosis were
seen. All toxicological effects were limited to the stomach, and could be attributable to the
strong alkaline corrosivity of the test substance. No further toxicologically significant changes
in any parental, reproductive or developmental parameter were observed. The No Observed
Adverse Effect Level (NOAEL) for parental toxicity was 50 mg/kg bw/d.
Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations checked in table [No.?] were included.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily
- Mortality: A check was made twice a day on working days or once a day on Saturdays, Sundays or on
public holidays (GD 0-20).
- Clinical symptoms: A cage-side examination was conducted at least once daily before and after treatment period
(GD 0-5 and 20). During treatment period (GD 6-19) all rats were checked daily for any signs
of morbidity, pertinent behavioral changes and/or signs of overt toxicity before administration
as well as within 2 hours and within 5 hours after administration.

Food consumption
The consumption of food was recorded for the intervals GD 0-1, 1-3, 3-6, 6-8, 8-10, 10-13, 13-
15, 15-17, 17-19 and 19-20.

BODY WEIGHT: No
- Time schedule for examinations: All animals were weighed on GD 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20. The body weight
change of the animals was calculated based on the obtained results.
- Furthermore, the corrected body weight gain was calculated after terminal sacrifice (terminal
body weight on GD 20 minus weight of the unopened uterus minus body weight on GD 6).


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: Necropsy
On GD 20, the dams were sacrificed under isoflurane anesthesia by decapitation, in
randomized order.
After the dams had been sacrificed, they were necropsied and assessed for gross pathology,
in randomized order. The uteri and the ovaries were removed and the following data were
recorded:
- Weight of the unopened uterus
- Number of corpora lutea
- Number and distribution of implantation sites classified as:
• Live fetuses
• Dead implantations:
a) Early resorptions (only decidual or placental tissues visible or according to SALEWSKI
from uteri from apparently non-pregnant animals and the empty uterus horn in the
case of single horn pregnancy)
b) Late resorptions (embryonic or fetal tissue in addition to placental tissue visible)
c) Dead fetuses (hypoxemic fetuses which did not breathe spontaneously after the
uterus had been opened)
After the weight of the uterus had been determined, all subsequent evaluations of the dams
and the gestational parameters were conducted by technicians unaware of treatment group in
order to minimize bias. For this purpose animal numbers were encoded.

OTHER:
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Dead fetuses (hypoxemic fetuses which did not breathe spontaneously after the
uterus had been opened)
Fetal examinations:
EXAMINATIONS OF THE FETUSES
All fetal analyses were conducted by technicians unaware of the treatment group, in order to
minimize bias.

Examinations of the fetuses after dissection from the uterus
At necropsy each fetus was weighed, sexed, and external tissues and all orifices were examined
macroscopically. The sex was determined by observing the distance between the anus
and the base of the genitalia.
Furthermore, the viability of the fetuses and the condition of placentae, umbilical cords, fetal
membranes, and fluids were examined. The placentas were weighed and their individual
weights were recorded.
Thereafter, the fetuses were sacrificed by a subcutaneous injection of pentobarbital
(Narcoren®; dose: 0.1 mL/fetus).
After these examinations, approximately one half of the fetuses per dam were eviscerated,
skinned and fixed in ethanol; the other half were placed in Harrison’s fluid for fixation.

Soft tissue examination of the fetuses
The fetuses fixed in Harrison’s fluid were examined for any visceral findings according to the
method of BARROW and TAYLOR. After this examination these fetuses were discarded.

Skeletal examination of the fetuses
The skeletons of the fetuses fixed in ethanol were stained according to a modified method of
KIMMEL and TRAMMELL. Thereafter, the skeletons of these fetuses were examined under a
stereomicroscope. After this examination the stained fetal skeletons were archived individually.
Statistics:
1. Simultaneous comparison of all dose groups with the control group using the DUNNETT-test (two-sided) for the hypothesis of equal means (Food consumptiona), body weight, body weight change, corrected body weight gain (net maternal body weight change), carcass weight, weight of unopened uterus, number of corpora lutea, number of implantations, number of resorptions, number of live fetuses, proportions of preimplantation loss, proportions of postimplantation loss, proportions of resorptions, proportion of live fetuses in each litter, litter mean fetal body weight, litter mean placental weight)
2. Pairwise comparison of each dose group with the control group using FISHER'S EXACT test (onesided) for the hypothesis of equal proportions (Female mortality, females pregnant at terminal sacrifice, number of litters with fetal findings)
3. Pairwise comparison of each dose group with the control group using the WILCOXON-test (onesided) for the hypothesis of equal medians (Proportions of fetuses with malformations, variations and/or unclassified observations in each litter)
Historical control data:
yes
Clinical signs:
no effects observed
Description (incidence and severity):
No clinical signs or changes of general behavior, which may be attributed to the test substance, were detected in any female at dose levels of 15, 50 or 150 mg/kg bw/d during the entire study period.
Mortality:
no mortality observed
Description (incidence):
There were no substance-related or spontaneous mortalities in any females of all test groups.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
The mean body weights of the dams in test groups 1, 2 and 3 (15, 50 and 150 mg/kg bw/d) were in general comparable to the controls throughout the entire study period. The statistically significantly increased body weight gain value in test group 2 on GD 19-20 is considered as an incidental event.
The corrected body weight gain of test groups 1-3 (15, 50 and 150 mg/kg bw/d) revealed no difference of any biological relevance to the concurrent control group. Moreover, mean carcass weights remained also unaffected by the treatment (for details cf. "Attached background material").
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
The mean food consumption of the dams in test groups 1, 2 and 3 (15, 50 or 150 mg/kg bw/d) was generally comparable to the concurrent control throughout the entire study period. The statistically significantly decreased food consumption value during the pre-treatment period (GD 1-3) in test group 3 as well as the statistically significantly increased value on GD 19-20 (same test group) are considered as incidental events.
Food efficiency:
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
not examined
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Description (incidence and severity):
No necropsy findings which could be attributed to the test substance were seen in any dam.
Histopathological findings: neoplastic:
not examined
Other effects:
no effects observed
Number of abortions:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Total litter losses by resorption:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Early or late resorptions:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Dead fetuses:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Changes in pregnancy duration:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.DescriptionIncidenceAndSeverityEffectsOnPregnancyDuration): For details cf. "Attached background material"
Changes in number of pregnant:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material"
Other effects:
no effects observed
Details on maternal toxic effects:
Uterus weight
The mean gravid uterus weights of the animals of test groups 1-3 (15, 50 and 150 mg/kg bw/d)
were not influenced by the test substance. The differences between these groups and the
concurrent control groups revealed no dose-dependency and were assessed to be without
biological relevance.

Reproduction data
The conception rate reached 96% in the control group and 100% in the low-, mid- and highdose
groups (15, 50 and 150 mg/kg bw/d). With these rates, a sufficient number of pregnant
females were available for the purpose of the study.
There were no test substance-related and/or biologically relevant differences between the test
groups 0-3 in conception rate, in the mean number of corpora lutea and implantation sites or
in the values calculated for the pre- and the postimplantation losses, the number of resorptions
and viable fetuses. All observed differences are considered to reflect the normal range of fluctuations
for animals of this strain and age, for details see also historical control data (cf. "Attached background material").

Key result
Dose descriptor:
NOAEL
Effect level:
150 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Key result
Abnormalities:
no effects observed
Fetal body weight changes:
no effects observed
Description (incidence and severity):
The mean fetal weights of test groups 1, 2 and 3 were not influenced by the test substance
and did not show any biologically relevant differences in comparison to the concurrent control
group. For details cf. "Attached background material".
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): For details cf. "Attached background material".
Reduction in number of live offspring:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material".
Changes in sex ratio:
no effects observed
Description (incidence and severity):
The sex distribution of the fetuses in test groups 1-3 (15, 50 and 150 mg/kg bw/d) was
comparable to the concurrent control fetuses. For details cf. "Attached background material".
Changes in litter size and weights:
no effects observed
Description (incidence and severity):
For details cf. "Attached background material".
Changes in postnatal survival:
not examined
External malformations:
effects observed, non-treatment-related
Description (incidence and severity):
One fetus, each, in test groups 1 and 2 (15 and 50 mg/kg bw/d) had external malformations , both fetuses had associated skeletal malformations. The malformations were not related to dose since the high-dose group showed no malformations. The total incidence of external malformations in treated animals did not differ significantly from the concurrent control group and was covered by the historical control data. For details cf. "Attached background material".
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Several skeletal malformations were detected in fetuses of test groups 0-3 (0, 15, 50 and 150 mg/kg bw/d) affecting the skull, sternum and forelimb. Each, one fetus of test groups 1 and 2 had associated external findings. All other findings were single cases and not related to dose. Except of one finding (misshapen scapula), all findings can be found in the historical control data. Misshapen scapula was only observed in one single fetus in test group 1, not dose-related and, therefore, considered as incidental. All findings were not considered to be treatment-related. For details cf. "Attached background material".
Visceral malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Two soft tissue variations, i.e. dilated renal pelvis and dilated ureter, were detected in all test groups including the control (0, 15, 50 or 150 mg/kg bw/d). The total incidences in treated animals did not differ significantly from the control group and was comparable to the historical control data. For details cf. "Attached background material".
Other effects:
no effects observed
Details on embryotoxic / teratogenic effects:
Finally, fetal examinations revealed that there is no effect of the compound on the respective morphological structures up to the highest tested dose (150 mg/kg bw/d). For details cf. "Attached background material".
Key result
Dose descriptor:
NOAEL
Effect level:
150 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: tertogenicity / embryotoxicity
Key result
Abnormalities:
no effects observed
Key result
Developmental effects observed:
no
Treatment related:
no
Conclusions:
Under the conditions of this prenatal developmental toxicity study, the oral administration of 1,8-Diazabicyclo[5.4.0]undec-7-ene to pregnant Wistar rats from implantation to one day prior to the expected day of parturition (GD 6-19) at doses as high as 150 mg/kg bw/d caused neither evidence of maternal nor developmental toxicity. In conclusion, the no observed adverse effect level (NOAEL) for maternal and prenatal developmental toxicity is the highest tested dose of 150 mg/kg bw/d.
Executive summary:

In a prenatal developmental toxicity study the test substance 1,8-Diazabicyclo[5.4.0]undec- 7-ene was administered to pregnant Wistar rats daily by gavage from implantation to one day prior to the expected day of parturition (GD 6-19) to evaluate its potential maternal and prenatal developmental toxicity. Analyses confirmed the correctness of the prepared concentrations and the stability of the test substance in the vehicle. Generally, clinical observations including food consumption and body weight/body weight gain revealed no toxicologically relevant differences between the animals receiving 15, 50 and 150 mg/kg bw/d 1,8-Diazabicyclo[5.4.0]undec-7-ene and controls. No differences of toxicological relevance between the control and the treated groups (15, 50 or 150 mg/kg bw/d) were determined for any reproductive parameters, such as conception rate, mean number of corpora lutea, mean number of implantations, as well as pre- and postimplantation loss. Similarly, no influence of the test substance on fetal weight and sex distribution of the fetuses was noted at any dose. Overall, there was no evidence for toxicologically relevant adverse effects of the test substance on fetal morphology at any dose.

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
150 mg/kg bw/day
Species:
rat
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

No evidence of developmental toxicity was seen at the highest dose level of 150 mg/kg bw/d used in an OECD 422 screening study. Parental toxicity (local gastric irritation) and secondary effects were seen at this dose level.

The potential of DBU to cause developmental toxicity and/or teratogenicity was investigated in a modern GLP- and guideline-compliant OECD 414 study (BASF SE, 2017).

The test substance was administered to pregnant Wistar rats daily by gavage from implantation to one day prior to the expected day of parturition (GD 6-19) to evaluate its potential maternal and prenatal developmental toxicity. Analyses confirmed the correctness of the prepared concentrations and the stability of the test substance in the vehicle. Generally, clinical observations including food consumption and body weight/body weight gain revealed no toxicologically relevant differences between the animals receiving 15, 50 and 150 mg/kg bw/d and controls. No differences of toxicological relevance between the control and the treated groups (15, 50 or 150 mg/kg bw/d) were determined for any reproductive parameters, such as conception rate, mean number of corpora lutea, mean number of implantations, as well as pre- and postimplantation loss. Similarly, no influence of the test substance on fetal weight and sex distribution of the fetuses was noted at any dose. Overall, there was no evidence for toxicologically relevant adverse effects of the test substance on fetal morphology at any dose. Thus, the NOAEL for maternal and developmental toxicity/teratogenicity was determined to be 150 mg/kg bw.

Justification for classification or non-classification

No classification is proposed for reproductive toxicity in the absence of any evidence for reproductive or developmental toxicity according to Regulation (EC) No. 1272/2008.