Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 242-362-4 | CAS number: 18479-58-8
Endpoint summary
Administrative data
Key value for chemical safety assessment
Effects on fertility
Description of key information
A study with the test item similar to OECD 421 has been conducted as a preliminary study to a extended one-generation reproductive toxicity study (basic design) according to OECD guideline 443. The in-life phase of the preliminary study has been finished and the results will be included as soon as the report is finalized. The extended one-generation reproductive toxicity study has been started in November 2021 and the results will be included as soon as the study is finished and the final report is available.
Link to relevant study records
- Endpoint:
- extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)
- Study period:
- From 2021-11-17 to 2023-06-27 (estimated)
- Data waiving:
- other justification
- Justification for data waiving:
- other:
- Justification for type of information:
- JUSTIFICATION FOR DATA WAIVING
Based on an ECHA decision (decision number TPE-D-2114449866-32-01/F), an extended one-generation reproductive toxicity study (test method OECD TG 443) in rats by the oral route has been requested by ECHA. A dose-range finding study similar to OECD TG 421 has been conducted to determine the doses for the main study (see section 7.8.1). The requested OECD TG 443 study has been started on 17 November 2021 and follows the study design specifications made by ECHA:
- Ten weeks premating exposure duration for the parental (P0) generation;
- Dose level setting shall aim to induce systemic toxicity at the highest dose level;
- Cohort 1A (Reproductive toxicity);
- Cohort 1B (Reproductive toxicity) without extension to mate the Cohort 1B animals to produce the F2 generation.
Due to the high workload of the laboratories, the deadline of 31 May 2021 specified in ECHA decision TPE-D-2114449866-32-01/F cannot be met.The in-life phase of the study was completed in August 2022 and the final report is planned to be issued on 23 June 2023 according to Study Plan Amendment 7, p. 11 (see "Attached justification").
This section will be updated with the results of the EOGRTS as soon as the study is finalized (presumably end of 2023). - Reason / purpose for cross-reference:
- data waiving: supporting information
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 443 (Extended One-Generation Reproductive Toxicity Study)
- Version / remarks:
- Adopted 2018-06-25
- GLP compliance:
- yes
- Limit test:
- no
- Justification for study design:
- SPECIFICATION OF STUDY DESIGN FOR EXTENDED ONE-GENERATION REPRODUCTION TOXICITY STUDY WITH JUSTIFICATIONS:
- Premating exposure duration for parental (P0) animals: 10 weeks
- Basis for dose level selection: According to a dose-range study according to OECD guideline 421. The dose level setting aims to induce systemic toxicity at the highest dose level and/or some reproductive toxicity effects.
- Inclusion/exclusion of extension of Cohort 1B: Cohort 1B is not planned to be extended according to ECHA decision number TPE-D-2114449866-32-01/F as no triggers for extension were identified.
- Inclusion/exclusion of developmental neurotoxicity Cohorts 2A and 2B: Cohorts 2A and 2B are not planned to be included according to ECHA decision number TPE-D-2114449866-32-01/F as no triggers for extension were identified.
- Inclusion/exclusion of developmental immunotoxicity Cohort 3: Cohort 3 is not planned to be included according to ECHA decision number TPE-D-2114449866-32-01/F as no triggers for extension were identified.
- Route of administration: Oral - Species:
- rat
- Strain:
- Sprague-Dawley
- Details on species / strain selection:
- The Sprague-Dawley rat is an accepted strain by regulatory agencies
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Charles River (UK) Limited
- Females nulliparous and non-pregnant: Yes
- Age at study initiation: 28-35 days (P0 generation), 26-30 days (F1 generation)
- Weight at study initiation: Within a 30 g weight range (P0 generation)
- Fasting period before study: No
- Housing: Up to 4 animals/cage (except during mating and from gestation to weaning (females)) in polycarbonate cages
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: At least 5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 40-70
- Air changes (per hr): Air is filtered but not recirculated
- Photoperiod (hrs dark / hrs light): 12/12
IN-LIFE DATES: From day 1 to approx. day 120 (P0 males and females), approx. from day 101 to day 189 (cohort 1A), approx. from day 101 to day 196 (cohort 1B), approx. from day 101 to day 161 (cohort 1C) - Route of administration:
- oral: feed
- Vehicle:
- unchanged (no vehicle)
- Remarks:
- feed
- Details on exposure:
- PREPARATION OF DOSING SOLUTIONS: Will be included in the final report.
DIET PREPARATION
- Rate of preparation of diet: Will be included in the final report
- Mixing appropriate amounts with: Will be included in the final report
- Storage temperature of food: Will be included in the final report - Details on mating procedure:
- - M/F ratio per cage: 1/1
- Length of cohabitation: Up to 2 weeks
- Proof of pregnancy: Ejected copulation plugs and/or sperm within vaginal smear referred to as day 0 of gestation
- Further matings after two unsuccessful attempts: No
- After successful mating each pregnant female was caged (how): Singly - Analytical verification of doses or concentrations:
- yes
- Details on analytical verification of doses or concentrations:
- At specified intervals during treatment, the test diets will be analyzed for achieved concentration of the test item. Analysis for achieved concentration will be performed and reported according to GLP regulations as part of this current study. The method of analysis will be documented in the study data and a summary included in the final report. The analytical method will involve the extraction of the test formulations with a suitable solvent followed by chromatographic assay. The formulated samples will be analyzed using a method validated with respect to the determination of the specificity of analysis, limits of detection, linearity of detector response, repeatability, method accuracy and precision.
- Duration of treatment / exposure:
- F0 animals: For 10 weeks before pairing until termination after litters are weaned.
Unselected F1 offspring: No direct treatment - killed on Day 22 of age
Cohort 1A: From weaning until approx. 13 weeks of age (Day 90)
Cohort 1B: From weaning to approximately 14 weeks of age
Cohort 1C: From weaning to completion of sexual maturation (approximately 6-8 weeks of age) - Frequency of treatment:
- Continuously through feed
- Details on study schedule:
- - If mating of the F1 generation is triggered, animals paired at no less than 14 weeks of age.
- Selection of parents from F1 generation when pups are 18-20 days of age.
- Dose / conc.:
- 11 000 ppm (nominal)
- Remarks:
- Selected F1 generation animals for nominal weeks 5 and 6 of age. Dietary levels will be closely monitored and may be increased during the progress of the selected F1 generation should the overall mean achieved dose fall close to or below 900 mg/kg/day for Group 4.
- Dose / conc.:
- 5 500 ppm (nominal)
- Remarks:
- Selected F1 generation animals for nominal weeks 5 and 6 of age. Dietary levels will be closely monitored and may be increased during the progress of the selected F1 generation should the overall mean achieved dose fall close to or below 900 mg/kg/day for Group 4.
- Dose / conc.:
- 2 750 ppm (nominal)
- Remarks:
- Selected F1 generation animals for nominal weeks 5 and 6 of age. Dietary levels will be closely monitored and may be increased during the progress of the selected F1 generation should the overall mean achieved dose fall close to or below 900 mg/kg/day for Group 4.
- Dose / conc.:
- 7 500 ppm (nominal)
- Remarks:
- F0 females in lactation and selected F1 generation animals to the end of nominal Week 4 of age
- Dose / conc.:
- 3 750 ppm (nominal)
- Remarks:
- F0 females in lactation and selected F1 generation animals to the end of nominal Week 4 of age
- Dose / conc.:
- 1 875 ppm (nominal)
- Remarks:
- F0 females in lactation and selected F1 generation animals to the end of nominal Week 4 of age
- Dose / conc.:
- 15 000 ppm (nominal)
- Remarks:
- F0 animals (except for females during lactation) and selected F1 generation animals from nominal Week 7 of age
- Dose / conc.:
- 7 500 ppm (nominal)
- Remarks:
- F0 animals (except for females during lactation) and selected F1 generation animals from nominal Week 7 of age
- Dose / conc.:
- 3 750 ppm (nominal)
- Remarks:
- F0 animals (except for females during lactation) and selected F1 generation animals from nominal Week 7 of age
- Dose / conc.:
- 0 ppm (nominal)
- Remarks:
- Control group
- No. of animals per sex per dose:
- 24 animals per sex per dose (P0), 20 animals per sex per cohort per dose (F1)
- Control animals:
- yes, plain diet
- Details on study design:
- - Dose selection rationale: Dietary levels were selected based on the findings of the Preliminary Reproductive Performance Study (Study No. 8446771, see IUCLID section 7.8.1). In that study, dietary administration of the test item at inclusion levels up to and including 15000 ppm was generally well tolerated for F0 males and F0 females in all phases with the exception of the lactation period. Three females given 15000 ppm were killed for welfare reasons on Day 20 of lactation, following signs of thin build and piloerection, these observations were first observed on Day 12 of lactation or later. With the exception of signs observed during lactation for females given 15000 ppm. there were no test item-related changes in general clinical condition among F0 generation animals.
- Fasting period before blood sampling for clinical biochemistry: Overnight - Positive control:
- Not included
- Parental animals: Observations and examinations:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: At least twice daily
- Cage side observations include: Evidence of reaction to treatment or ill-health
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Once each week for all F0 and selected F1 generation animals. For F0 females on Days 0, 5, 12, 18 and 20 after mating and Days 1, 7, 14 and 21 of lactation for F0 females.
- Detailed clinical observations include: Physical condition and behavior during handling, signs of neurotoxicity such as convulsions, tremor and abnormalities of gait or behavior.
BODY WEIGHT: Yes
- Time schedule for examinations: Day that treatment commences, afterwards each week and before necropsy (F0 males); day that treatment commences, afterwards each week until mating detected, days 0, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 after mating, days 1, 4, 7, 11, 14, 18, 21 and 28 post-partum and before necropsy (F0 females); days 21, 23, 24, 25, 26, 27, and 28 of age, from nominal 4 weeks of age, twice during Weeks 1, 2 and 3 of the F1 generation and weekly thereafter and before necropsy (F1 animals)
FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes
WATER CONSUMPTION AND COMPOUND INTAKE: No - Oestrous cyclicity (parental animals):
- Dry smears: For 15 days before pairing
Wet smears: Daily after pairing until evidence of mating confirmed, using pipette lavage and on the day of scheduled necropsy
For females showing no evidence of mating: Following completion of the pairing period the females will be separated from the male and vaginal smearing will continue for up to five days or until the first estrus smear is seen. If a female shows an estrus smear during this period, the female will be killed as soon as practically possible and subject to macroscopic examination. If a female does not show an estrus smear, a wet smear will be taken on the morning of necropsy (Day 25 after removal from pairing where Day 0 = day of removal from pairing - Sperm parameters (parental animals):
- Parameters examined in all P0 and F1 Cohort 1A males:
Testis weight, epididymis weight, sperm count in testes, sperm count in epididymides, enumeration of cauda epididymal sperm reserve, sperm motility, sperm morphology - Litter observations:
- STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: Yes
- If yes, maximum of 10 pups/litter (5/sex/litter as nearly as possible); excess pups will be killed and discarded.
PARAMETERS EXAMINED
The following parameters were examined in F1offspring:
Number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities, anogenital distance (AGD), pup weight on the day of AGD, presence of nipples/areolae in male pups. Particular attention is paid to the external reproductive genitals which will be examined for signs of altered development; gross evaluation of external genitalia
GROSS EXAMINATION OF DEAD PUPS:
Yes, for external and internal abnormalities. Where possible, decedent offspring ≤21 days of age (found dead or welfare kill) will be examined and carcass retained. - Postmortem examinations (parental animals):
- SACRIFICE
- Male animals: All surviving animals after at least 18 weeks of treatment and after weaning of the F1 animals, after confirmation that no further mating is required.
- Maternal animals: All surviving animals on day 28 postpartum
GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.
HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated in Table 1 will be prepared for microscopic examination and weighed, respectively. - Postmortem examinations (offspring):
- GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.
HISTOPATHOLOGY / ORGAN WEIGTHS
The tissues indicated in Table 2-5 were prepared for microscopic examination and weighed, respectively. - Statistics:
- For categorical data, the proportion of animals will be analyzed for each treated group (as appropriate) versus the control group. For continuous data, Bartlett’s test will first be applied to test the homogeneity of variance between the groups. Using tests dependent on the outcome of Bartlett’s test, treated groups will then be compared with the control group, incorporating adjustment for multiple comparisons where necessary. Alternative or additional methods may be carried out if deemed appropriate following data review. Details will be included in the study report.
- Reproductive indices:
- Percentage mating: (Number animals mating / Animals paired) x 100;
Conception rate: (Number animals achieving pregnancy / Animals mated) x 100;
Fertility index: (Number animals achieving pregnancy / Animals paired) x 100;
Gestation index: (Calculated for each group as: Number of live litters born / Number pregnant) x 100 - Offspring viability indices:
- Post-implantation survival index: (Total number of offspring born / Total number uterine implantation sites) x 100;
Live birth index: (Number live offspring on Day 1 after littering / Total number of offspring born) x 100;
Viability index: (Number live offspring on Day 4 before culling / Number live offspring on Day 1 after littering) x 100;
Lactation index: (Number live offspring on Day 21 after littering / Number live offspring on Day 4 (after culling)) x 100;
Sex ratio: Individual litter values tabulated for total at Day 1 and live at Days 1, 4 (before and after cull) and Day 21 of age;
Individual litter values tabulated for total at Day 1 and live at Days 1, 4 (before and after cull) and Day 21 of age;
Sexual maturation: Individual values tabulated for age and body weight at completion. - Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Key result
- Dose descriptor:
- NOAEL
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- other: Will be updated after completion of the study.
- Key result
- Critical effects observed:
- not specified
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Behaviour (functional findings):
- not examined
- Description (incidence and severity):
- Will be updated after completion of the study.
- Developmental immunotoxicity:
- not examined
- Description (incidence and severity):
- Will be updated after completion of the study.
- Key result
- Dose descriptor:
- NOAEL
- Generation:
- F1
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- other: Will be updated after completion of the study.
- Key result
- Critical effects observed:
- not specified
- Key result
- Reproductive effects observed:
- not specified
- Endpoint:
- screening for reproductive / developmental toxicity
- Study period:
- 2021-02-24 to 2021-12-17 (estimated)
- Data waiving:
- other justification
- Justification for data waiving:
- other:
- Justification for type of information:
- JUSTIFICATION FOR DATA WAIVING
Based on an ECHA decision (decision number TPE-D-2114449866-32-01/F), an extended one-generation reproductive toxicity study (test method OECD TG 443) in rats by the oral route has been requested by ECHA. A dose-range finding study similar to OECD TG 421 has been conducted to determine the doses for the main study. The in-life phase of the study has been completed and the results will be included as soon as the final report ist available. - Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
- Deviations:
- yes
- Remarks:
- Not all parameters measured as the study was conducted as a range finding study for the main OECD 443 study.
- GLP compliance:
- no
- Remarks:
- No claim of compliance with Good Laboratory Practice (GLP) will be made for this study; however, the work performed will be followed good scientific practices and adhere to the study plan, any amendments and applicable SOPs.
- Limit test:
- no
- Justification for study design:
- The study design was chosen on the basis of OECD guideline 421.
- Species:
- rat
- Strain:
- Sprague-Dawley
- Remarks:
- Crl:CD(SD)
- Details on species / strain selection:
- The Sprague-Dawley rat (sexually mature and virgin) is an accepted species for reproductive toxicity studies by regulatory agencies and historical control data are available.
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Females nulliparous and non-pregnant: Yes
- Age at study initiation: (P) 10-12 weeks; (F1) 4 weeks
- Weight at study initiation: (P) Males: 351-400 g; Females: 227-254 g; (F1) Males: will be added when the study is finished; Females: will be added when the study is finished
- Fasting period before study: Not indicated
- Housing: Polycarbonate caging with stainless steel grid (pairing period) or with solid polycarbonate floor (rest of the study) with softwood based bark-free fiber, sterilized by autoclaving
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: At least 5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 40-70
- Air changes: Air will be filtered, not recirculated
- Photoperiod (hrs dark / hrs light): 12/12
IN-LIFE DATES: From day 0 to approx. day 60 (F0 females), from day 0 to approx. day 37 (F0 males), from approx. day 37 to approx. day 91 (F1 offspring) - Route of administration:
- oral: feed
- Vehicle:
- other: Will be documented in the study data and included in the final report.
- Details on exposure:
- PREPARATION OF DOSING SOLUTIONS:
Unless advised otherwise, the procedure for production of a premix includes grinding the test item/diet admixture.
DIET PREPARATION
- Rate of preparation of diet: Weekly, and up to one week in advance of first feeding.
- Mixing appropriate amounts with: SDS VRF1
- Storage temperature of food: Prepared diets will be stored frozen (-10 to -30 °C). Formulated diets may be stored at ambient temperature (15 to 25ºC) (once defrosted), within the confirmed stability period of up to 8 days, pending feeding and accounting for the time in the food hoppers. - Details on mating procedure:
- - M/F ratio per cage: 1.1
- Length of cohabitation: Up to 2 weeks
- Proof of pregnancy: Vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy.
- Further matings after two unsuccessful attempts: A female showing no evidence of mating after completion of the pairing period will be separated from the male and vaginal smearing will be continued for up to five days or until the first estrus smear is seen. If an estrus smear is seen during this period, the female cannot be pregnant and will be dispatched to necropsy as soon as practically possible. If an estrus smear is not seen the female will be dispatched to necropsy on or after day 25 after the last day of pairing.
- After successful mating each pregnant female was caged: Singly to permit collection of food consumption data individually for pregnant females and during lactation. - Analytical verification of doses or concentrations:
- no
- Remarks:
- No formulation analysis will be performed on this study but was tested as part of another study (see below).
- Details on analytical verification of doses or concentrations:
- The homogeneity and stability of the test item in the diet during storage were confirmed as part of another study. In that study, prepared diets in the range 1500 to 15000 ppm were determined to be stable for:
- 8 days at ambient temperature (15 to 25 °C)
- 15 days when stored frozen (-10 to -30 °C)
Prepared diets will be stored frozen (-10 to -30 °C) until required for feeding. - Duration of treatment / exposure:
- F0 females: Two weeks before pairing until Day 21 of lactation (approx. 60 days); F0 males: two weeks before pairing until after successful littering by females (approx. 37 days); F1 litters: From late lactation when offspring start to consume diet (approx. in the age of 28 days) to approximately week 7 of age after sexual maturity has been attained (approx. 26 days)
- Frequency of treatment:
- Continuously
- Dose / conc.:
- 0 ppm
- Remarks:
- control
- Dose / conc.:
- 3 750 ppm (nominal)
- Remarks:
- Expected achieved doses: Approx. 225 mg/kg/day (males) and 235 mg/kg/day (females)
- Dose / conc.:
- 7 500 ppm (nominal)
- Remarks:
- Expected achieved doses: Approx. 456 mg/kg/day (males) and 485 mg/kg/day (females)
- Dose / conc.:
- 15 000 ppm (nominal)
- Remarks:
- Expected achieved doses: Approx. 886 mg/kg/day (males) and 842 mg/kg/day (females)
- No. of animals per sex per dose:
- 8 animals per sex per dose (F0 generation), 10 animals per sex per dose (F1 generation)
- Control animals:
- yes, plain diet
- Details on study design:
- - Dose selection rationale: The dietary levels for this study have been selected in consultation with the sponsor, based on the results of a 21-Day palatability study in Sprague Dawley Rats by dietary administration (see section 7.5.1). In this study, no premature decedents or treatment-related changes in clinical conditions were observed and only some slight effects on body weight and liver weight were observed. Thus the highest dose used in the palatibility study (15000 ppm, resulting in mean achieved doses of 886 mg/kg/day in males and 842 mg/kg/day in females) was chosen also for this dose-range finding test.
- Fasting period before blood sampling for clinical biochemistry: Animals were not fasted before blood sampling and clinical biochemistry. - Positive control:
- Not included
- Parental animals: Observations and examinations:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily
- Cage side observations included: Evidence of reaction to treatment or ill-health
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Twice weekly; days 0, 3, 7, 10, 14, 18 and 20 after mating and days 1, 4, 7, 10, 14, 18 and 21 of lactation for F0 females.
BODY WEIGHT: Yes
- Time schedule for examinations: Twice weekly and at the day of necropsy (F0 males), twice weekly until mating detected; days 0, 3, 7, 10, 14, 17 and 20 after mating and on days 1, 4, 7, 11, 14, 18 and 21 of lactation (F0 females); days 21, 23, 25, 27 and 28 of age and twice weekly from nominal 4 weeks of age to termination at approximately 7 weeks of age (F1 animals)
FOOD CONSUMPTION AND COMPOUND INTAKE
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Not specified
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Not specified
HEMATOLOGICAL ANALYSIS
- Time schedule for examinations: At termination (no overnight deprivation of food)
- Anaesthetic: Isoflurane
- Parameters examined: Thyroid hormones, hematocrit, hemoglobin concentration, erythrocyte count, total leucocyte count, differential leucocyte count, platelet count, mean cell hemoglobin, mean cell volume, mean cell hemoglobin concentration, red cell distribution width, prothrombin time, activated partial thromboplastin time
- Oestrous cyclicity (parental animals):
- The oestrus cycle will be determined by dry smears (for 15 days before pairing, using cotton swabs) and by wet smears (after pairing until evidence of mating confirmed, using pipette lavage). Percentages of females showing the following cycle types will be calculated:
- Regular (all observed cycles are of 4 or 5 days; may be divided into cycles of 4, 4 and 5, and 5 days, if inter-group differences are apparent),
- Irregular: At least one cycle of 2, 3 or 6 to 10 days.
- Acyclic: At least 10 days without estrus (beginning before pairing). - Sperm parameters (parental animals):
- Sperm parameters will not be examined.
- Litter observations:
- STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: Yes
- A maximum of 5 pups/sex/litter were selected. Excess pups were killed and discarded.
PARAMETERS EXAMINED
The following parameters were examined in F1 offspring: Number and sex of pups, sex ratio, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical and behaviour abnormalities, anogenital distance (AGD), gross evaluation of external genitalia
GROSS EXAMINATION OF DEAD PUPS:
Yes, for external abnormalities with assessment of stomach for presence of milk, where possible. Abnormal tissues retained in an appropriate fixative.
ASSESSMENT OF DEVELOPMENTAL NEUROTOXICITY: No
ASSESSMENT OF DEVELOPMENTAL IMMUNOTOXICITY: No - Postmortem examinations (parental animals):
- SACRIFICE
- Male animals: All surviving animals, after successful littering by females
- Maternal animals: All surviving animals on day 21 of lactation. If females will fail to produce viable litter on day 25 after mating, if litters die before weaning, on day last offspring dies. If females fail to mate, on or after day 25 after last day of pairing OR day of confirmed estrus after failure to mate.
GROSS NECROPSY
- Gross necropsy consists of external examinations (see table 1).
HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated in table 1 will be prepared for microscopic examination and weighed, respectively. Any abnormal tissues retained and may be weighed at the discretion of necropsy staff. In addition, the following will be recorded for all F0 females (including those prematurely sacrificed, where possible): number of implantation sites, mammary tissue appearance for females whose litter dies before day 21 of lactation. - Postmortem examinations (offspring):
- SACRIFICE
- The F1 offspring not selected are sacrificed at 4 days of age.
- These animals are subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows: Culled offspring with clinical signs on day 4 of age will be subject to complete macroscopic examination with assessment of stomach for presence of milk, where possible. Abnormal tissues retained in an appropriate fixative. Culled offspring with no clinical sign on Day 4 of age will be killed and discarded without necropsy examination.
GROSS NECROPSY
- Gross necropsy consisted of complete external examinations. Organs are weighted (see table 2).
HISTOPATHOLOGY / ORGAN WEIGTHS
Abnormal tissues will be retained in an appropriate fixative and checked histopathologically (see table 2). - Statistics:
- The following data types will be analyzed at each timepoint separately, where required, in support of interpretation: body weight, using absolute weights and gains over appropriate study periods; food consumption, over appropriate study periods; organ weights, both absolute and relative to body weight estrous cycles and vaginal opening to first estrous; pre-coital interval; mating performance and fertility; gestation length and gestation index; litter data; thyroid hormones.
For categorical data, the proportion of animals will be analyzed for each treated group (as appropriate) versus the control group. For continuous data, Bartlett’s test will first be applied to test the homogeneity of variance between the groups. Using tests dependent on the outcome of Bartlett’s test, treated groups will then be compared with the control group, incorporating adjustment for multiple comparisons where necessary. - Reproductive indices:
- Percentage mating (Number animals mating x 100 / Animals paired), conception rate (Number animals achieving pregnancy x 100 / Animals mated), fertility index (number animals achieving pregnancy x 100 / Animals paired)
- Offspring viability indices:
- Post-implantation survival index (Total number offspring born x 100 / Total number uterine implantation sites), Live birth index (Number live offspring on Day 1 after littering x 100 / Total number of offspring born), Viability index (Number live off spring on Day 4 before culling x 100 / Number live off spring on Day 1 after littering), Lactation index (Number live off spring on Day 21 after littering x 100 / Number live off spring on Day 4 (after culling)
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Key result
- Dose descriptor:
- NOAEL
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- other: Will be updated after completion of the study.
- Key result
- Critical effects observed:
- not specified
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Description (incidence and severity):
- Will be updated after completion of the study.
- Key result
- Dose descriptor:
- NOAEL
- Generation:
- F1
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- other: Will be updated after completion of the study.
- Key result
- Critical effects observed:
- not specified
- Key result
- Reproductive effects observed:
- not specified
- Executive summary:
An oral feeding study with the test item in male and female Sprague Dawley rats similar to OECD 421 is currently running as a preliminary study to a extended one-generation reproductive toxicity study (basic design) according to OECD guideline 443. The nominal dose range was chosen between 0 and 15000 ppm, which is expected to result in actual achieved doses of approx. 225 to 886 mg/kg bw/day (as determined in a 21-day palatability study, please refer to section 7.5.1). Clinical signs, body weight, food consumption, hematology, gross pathology estrus cyclicity and number of implantation sites + mammary tissue appearance (for females whose litter die before day 21 of lactation) will be examined in the P0 generation. Litters will be evaluated for number and sex of pups, sex ratio, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical and behaviour abnormalities, anogenital distance (AGD) and gross evaluation of external genitalia. Reproductive indices and offspring viability indices will be calculated. This section will be updated with the results of the OECD 421 study as soon as the study is finalized.
Referenceopen allclose all
Effect on fertility: via oral route
- Endpoint conclusion:
- no study available
- Species:
- rat
Effect on fertility: via inhalation route
- Endpoint conclusion:
- no study available
Effect on fertility: via dermal route
- Endpoint conclusion:
- no study available
Additional information
- Ten weeks premating exposure duration for the parental (P0) generation;
- Dose level setting shall aim to induce systemic toxicity at the highest dose level;
- Cohort 1A (Reproductive toxicity);
- Cohort 1B (Reproductive toxicity) without extension to mate the Cohort 1B animals to produce the F2 generation.
Toxicity to reproduction, screening for reproductive/developmental toxicity
An oral feeding study with the test item in male and female Sprague Dawley rats similar to OECD 421 has been conducted as a preliminary study to a extended one-generation reproductive toxicity study (basic design) according to OECD guideline 443. The nominal dose range was chosen between 0 and 15000 ppm, which is expected to result in actual achieved doses of approx. 225 to 886 mg/kg bw/day (as determined in a 21-day palatability study, please refer to section 7.5.1). Clinical signs, body weight, food consumption, hematology, gross pathology estrus cyclicity and number of implantation sites + mammary tissue appearance (for females whose litter die before day 21 of lactation) will be examined in the P0 generation. Litters will be evaluated for number and sex of pups, sex ratio, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical and behaviour abnormalities, anogenital distance (AGD) and gross evaluation of external genitalia. Reproductive indices and offspring viability indices will be calculated. This section will be updated with the results of the preliminary study as soon as the study is finalized.
Toxicity to reproduction, extended one-generation reproductive toxicity study
Based on an ECHA decision (decision number TPE-D-2114449866-32-01/F), an extended one-generation reproductive toxicity study (test method OECD TG 443) in rats by the oral route has been requested. The study has been started in November 2021.
The test design follows the subsequent study-design specifications made by ECHA:
Sufficient mating pairs to produce 20 animals per dose group (P generation) are used. Cohort 1B will not be extended to produce the F2 generation, as the substance is not classified as mutagenic in vivo (cat. 2), there is no evidence that the internal dose of the substance/metabolites reaches an equilibrium state only after prolonged exposure, and there is no evidence from in vivo studies or other methods that there are relevant modes of action related to endocrine disruption. No inclusion of cohorts 2A and 2B (developmental neurotoxicity) and cohort 3 (developmental immunotoxicity) is intended as no signs of neurotoxicity or immunotoxicity of the substance has been observed in any of the repeated dose toxicity studies. A ten-week premating exposure duration for the parental (P0) generation was chosen. Dose level selection was based on the dose range finding study which is currently finalized. This section will be updated with the results of the EOGRTS soon as the study is finalized.
Effects on developmental toxicity
Description of key information
On the basis of the data from a developmental toxicity study in rats, meeting the requirements of the Food and Drug Administration for the evaluation of ICH Harmonized Tripartite Guideline stages C and D of the reproductive process with the analogue substance dimyrcetol, the maternal no-observable-adverse-effect-level (NOAEL) was 1000 mg/kg bw/day. The 500 mg/kg bw/day dose level was assigned as the NOEL for maternal effects. The developmental NOAEL was also 1000 mg/kg bw/day. The 500 mg/kg bw/day dose level was assigned as the NOEL for developmental effects.
A Pre-natal developmental toxicity study (PNDT, Annex X, Section 8.7.2.; test method: OECD TG 414) by oral route, in a second species (rabbit) will be conducted following the study design specifications made by ECHA (OECD 414, rabbit, oral route). This section will be updated with the results of the PNDT study as soon as the study is finalized.
Link to relevant study records
- Endpoint:
- developmental toxicity
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study with acceptable restrictions
- Qualifier:
- according to guideline
- Guideline:
- other: US FDA; This study was designed to evaluate ICH Harmonised Tripartite Guideline stages C and D of the reproductive process
- Deviations:
- not specified
- GLP compliance:
- yes (incl. QA statement)
- Limit test:
- no
- Species:
- rat
- Strain:
- Sprague-Dawley
- Remarks:
- Cr1:CD(SD)
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Age at arrival: 62 days (approximate)
- Weight at study initiation: 218 to 244 g
- Fasting period before study: None
- Housing: Individually in stainless steel, wire-bottomed cages (except during cohabitation)
- Diet: Ad libitum. Certified Rodent Diet #5002 (PMI Nutrition International, St. Louis, MO)
- Water: Ad libitum. Local water processed by reverse osmosis. Chlorine added as bacteriostat
- Acclimation period: Yes, but duration not stated
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17.8-26.1 (targeted)
- Humidity (%): 30 to 70 (targeted)
- Air changes (per hr): 10 (minimum)
- Photoperiod (hrs dark / hrs light): 12/12 - Route of administration:
- oral: gavage
- Vehicle:
- corn oil
- Details on exposure:
- PREPARATION OF DOSING SOLUTIONS:
Suspensions of the test article were prepared weekly at the testing facility. Prepared formulations were stored at room temperature, protected from light.
VEHICLE
- Concentration in vehicle: The dosage preparations are shown in Table 1.
- Amount of vehicle: Constant dosage volume of 10 mL/kg - Details on analytical verification of doses or concentrations:
- Samples were analyzed according to the method described in Charles River Laboratories Preclinical Services. Results of concentration and homogeneity analyses were within +/- 15% of calculated concentrations and
- Details on mating procedure:
- After a suitable acclimation, 130 virgin female rats were placed into cohabitation with 130 breeder male rats, one male rat per female rat. The cohabitation period was a maximum of five days. Gestation day 0 was considered the first day when spermatozoa were detected in a vaginal smear or a copulatory plug was observed. Pregnant rats were assigned to individual housing.
- Duration of treatment / exposure:
- Rats were treated on gestation days 7 through 17. Dosages were adjusted daily based on the individual body weights recorded prior to dosage administration.
- Frequency of treatment:
- Once daily
- Duration of test:
- Until gestation day 21
- Dose / conc.:
- 1 000 mg/kg bw/day (nominal)
- Dose / conc.:
- 500 mg/kg bw/day (nominal)
- Dose / conc.:
- 250 mg/kg bw/day (nominal)
- Dose / conc.:
- 0 mg/kg bw/day (nominal)
- Remarks:
- Vehicle
- No. of animals per sex per dose:
- 25 female/dose group
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- - Dose selection rationale: Dosages were based on the results of a range-finding study with the same test article at a dosage level of 1000 mg/kg/day. This was selected as the highest dose in the current study.
- Rationale for route of administration: Oral (gavage) was selected for use as comparison with the dietary route; the exact dosage can be accurately determined. - Maternal examinations:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily (rats were observed for viability at least twice daily each day of the study and weekly for clinical observations and general appearance during the acclimation period and on DG 0)
- Cage side observations included: Clinical observations, abortions, premature deliveries and deaths before and approximately 3 hours after dosing, and once daily during the post-dosage period.
DETAILED CLINICAL OBSERVATIONS: No data
BODY WEIGHT: Yes
- Time schedule for examinations: Weekly during the acclimation period, on DG 0 and daily during the dosage and post-dosage periods
FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data
WATER CONSUMPTION AND COMPOUND INTAKE: No data
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: Thoracic, abdominal and pelvic viscera. Gross lessions were retained in neutral-buffered 10% formalin for possible future evaluation. Unless specifically cited, all other tissues were discarded. - Ovaries and uterine content:
- The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Placentae were examined for size, color and shape. Number and distribution of live and dead fetuses were recorded. - Blood sampling:
- - Plasma: No
- Serum: No - Fetal examinations:
- - External examinations: Yes (all per litter)
- Soft tissue examinations: Yes (half per litter)
- Skeletal examinations: Yes (half per litter)
- Head examinations: No data
- Anogenital distance of all live rodent pups: Not specified - Statistics:
- Clinical observations and other proportional data were analyzed using the Variance Test for Homogeneity of the Binomial Distribution. Continuous data (e.g., body weights, body weight changes, feed consumption values, and litter averages for percent male fetuses, percent resorbed conceptuses, fetal body weights and fetal anomaly data) were analyzed using Bartlett’s Test of Homogeneity of Variances and the Analysis of Variance, when appropriate [i.e., Bartlett’s Test was not significant (p>0.001)]. If the Analysis of Variance was significant (p≤0.05), Dunnett’s Test was used to identify the statistical significance of the individual groups. If the Analysis of Variance was not appropriate [i.e., Bartlett’s Test was significant (p≤0.001)], the Kruskal-Wallis Test was used, when less than or equal to 75% ties were present. In cases where the Kruskal-Wallis Test was statistically significant (p≤0.05), Dunn’s Method of Multiple Comparisons was used to identify the statistical significance of the individual groups. If there were greater than 75% ties, Fisher’s Exact Test was used to analyze the data. Count data obtained at Caesarean-sectioning of the dams were evaluated using the procedures described above for the Kruskal-Wallis Test.
- Historical control data:
- Historical control data was available from this laboratory for the period from January 2005 to January 2007.
- Clinical signs:
- effects observed, non-treatment-related
- Description (incidence and severity):
- Minor incidences of sparse hair coat or localized alopecia, excess salivation, urine-stained abdominal fur, ungroomed coat, rales, ptosis, chromodacryorrhea (colored tears), and soft or liquid feces. These observations were all considered unrelated to the treatment because the incidences were observed in vehicle control rats, were not dosage dependent, or were transient and did not persist.
- Mortality:
- no mortality observed
- Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- 1000 mg/kg bw/day: Body weight gains for the entire dosage period were reduced by 5% when compared with controls, an observation that was not statistically significant but was considered evidence of a threshold for maternal toxicity.
- Food consumption and compound intake (if feeding study):
- effects observed, treatment-related
- Description (incidence and severity):
- 1000 mg/kg bw/day: Absolute (g/d) and relative (g/kg/d) feed consumption values were significantly reduced for the entire dosage period.
- 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
- Endocrine 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:
- no effects observed
- Description (incidence and severity):
- No gross lesions were noted at necropsy.
- Neuropathological findings:
- not examined
- Histopathological findings: non-neoplastic:
- no effects observed
- Histopathological findings: neoplastic:
- no effects observed
- Other effects:
- no effects observed
- Number of abortions:
- not examined
- Pre- and post-implantation loss:
- no effects observed
- 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
- Changes in number of pregnant:
- no effects observed
- Other effects:
- not examined
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 1 000 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 500 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- Key result
- Abnormalities:
- no effects observed
- Fetal body weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- 1000 mg/kg bw/day: Body weights for combined male and female fetuses were reduced approximately 3%. The reduction in female fetuses was statistically significant (P ≤ .05).
- Reduction in number of live offspring:
- no effects observed
- Changes in sex ratio:
- no effects observed
- Changes in litter size and weights:
- no effects observed
- Anogenital distance of all rodent fetuses:
- not examined
- Changes in postnatal survival:
- not specified
- External malformations:
- no effects observed
- Skeletal malformations:
- no effects observed
- Visceral malformations:
- not examined
- Other effects:
- effects observed, treatment-related
- Description (incidence and severity):
- Significant increases in fetal variations attributable to the test article were observed only at the 1000 mg/kg bw/day dosage level. These changes consisted of reversible minor variations, including a threshold but statistically significant increase in supernumerary ribs, along with associated significant increases and decreases in the respective numbers of thoracic and lumbar vertebrae, and a small but statistically significant retardation in ossification of the metatarsal bones in the hindpaws, evident as a reduction in the mean number of ossified metatarsal bones.
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 500 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- fetal/pup body weight changes
- skeletal malformations
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 1 000 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- not determinable due to absence of adverse toxic effects
- Key result
- Abnormalities:
- not specified
- Key result
- Developmental effects observed:
- not specified
- Dosage occurred on days 7 through 17 of gestation.
- Excludes values that could not be calculated or appeared incorrectly recorded, as well as those associated with spillage.
- Studies (N = 44) conducted at the Testing Facility between January 2005 and January 2007 in rats of the same strain.
- Means and Standard Deviations
- Mean and range of means per study
- Bold = effect of test article because values were significant and/or exceeded historical ranges. DGs = Days of Gestation
- Conclusions:
- On the basis of these data, the maternal no-observable-adverse-effect-level (NOAEL) was 1000 mg/kg bw/day. At this dose level, maternal body weight gains were reduced (not significantly) and feed consumption was significantly reduced. The 500 mg/kg bwt/day dose level was assigned as the NOEL for maternal effects.
The developmental NOAEL was also 1000 mg/kg bw/day. This was based on minimal reductions in female fetal weights and small increases in reversible variations in skeletal ossification. The 500 mg/kg bw/day dose level was assigned as the NOEL for developmental effects. - Executive summary:
The test item was administered in corn oil by gavage to groups of pregnant Sprague-Dawley rats at dosages of 0, 250, 500 or 1000 mg/kg bw/day on gestational days 7 to 17. Viability, clinical signs, body weights and feed consumption were observed or measured for all animals. Animals were sacrificed on gestational day 21 and Caesarean sectioning performed. Fetuses were weighed and examined for sex, gross changes, and soft tissue or skeletal alterations. No clinical signs attributable to the test item administration were observed. At the 1000 mg/kg bw/day dose level, mean maternal body weight gains were reduced 5% versus controls. Absolute and relative feed consumption were also reduced at this dose level. The minimal maternal effects noted were associated with minimal (approx. 3%) reductions in fetal body weights, reversible variations in ossification and increases in supernumerary thoracic ribs with associated increases or decreases in thoracic and lumbar vertebrae, respectively. Findings of delayed skeletal ossification are generally considered readily reversible (Carney and Kimmel, 2007 "Interpretation of skeletal variations for human risk assessment: Delayed ossification and wavy ribs", Birth Defects Research 80:473 -496). The minimal developmental delays (reduced pup weights, delayed ossificaiton, changes in metatarsals) are all expected to be readily reversible based on studies that have investigated the progression and outcome of similar effects. On the basis of these data, the maternal no-observable-adverse-effect-level (NOAEL) was 1000 mg/kg bw/day. At this dose level, maternal body weight gains were reduced (not significantly) and feed consumption was significantly reduced. The 500 mg/kg bwt/day dose level was assigned as the NOEL for maternal effects.The developmental NOAEL was also 1000 mg/kg bw/day. This was based on minimal reductions in female fetal weights and small increases in reversible variations in skeletal ossification. The 500 mg/kg bw/day dose level was assigned as the NOEL for developmental effects.
Reference
Table 2: MATERNAL BODY WEIGHT GAINS - SUMMARY
DOSE GROUP |
| I | II | III | IV |
DOSAGE (mg/kg bwt/day) |
| 0 (control) | 250 | 500 | 1000 |
RATS TESTED | N | 25 | 25 | 25 | 25 |
PREGNANT | N | 22 | 24 | 24 | 25 |
MATERNAL BODY |
|
|
|
|
|
WEIGHT CHANGE (G) |
|
|
|
|
|
DAYS 0 - 7 | MEAN±S.D. | +42.5 ± 7.2 | +42.0 ± 8.2 | +40.7 ± 10.6 | +39.8 ± 7.5 |
DAYS 7 - 8 | MEAN±S.D. | -2.6 ± 4.6 | -0.4 ± 5.2 | -1.2 ± 5.5 | -4.1 ± 6.8 |
DAYS 8 - 9 | MEAN±S.D. | +1.4 ± 4.3 | +2.0 ± 5.6 | +1.5 ± 4.0 | -1.1 ± 6.2 |
DAYS 9 - 10 | MEAN±S.D. | +3.2 ± 4.6 | +4.0 ± 4.8 | +6.1 ± 4.2 | +5.4 ± 5.7 |
DAYS 7 - 10 | MEAN±S.D. | +2.0 ± 6.5 | +5.5 ± 7.0 | +6.4 ± 8.6 | +0.1 ± 9.4 |
DAYS 10 - 12 | MEAN±S.D. | +12.0 ± 5.3 | +14.8 ± 5.4 | +12.9 ± 5.2 | +11.8 ± 9.6 |
DAYS 12 - 15 | MEAN±S.D. | +17.7 ± 8.5 | +17.1 ± 9.5 | +19.8 ± 5.8 | +18.4 ± 7.3 |
DAYS 15 - 18 | MEAN±S.D. | +41.2 ± 9.6 | +39.4 ± 8.8 | +41.2 ± 7.3 | +39.0 ± 7.7 |
DAYS 7 - 18 | MEAN±S.D. | +73.0 ± 17.0 | +76.8 ± 15.2 | +80.2 ± 14.5 | +69.3 ± 15.1 |
DAYS 18 - 21 | MEAN±S.D. | +59.4 ± 11.4 | +54.2 ± 8.7 | +61.0 ± 10.8 | +58.1 ± 12.8 |
DAYS 7 - 21 | MEAN±S.D. | +132.4 ± 22.6 | +130.9 ± 16.7 | +141.2 ± 20.5 | +127.4 ± 20.5 |
DAYS 0 - 21 | MEAN±S.D. | +174.9 ± 25.6 | +173.0 ± 21.0 | +181.9 ± 27.2 | +167.2 ± 23.6 |
Table 3: MATERNAL RELATIVE FEED CONSUMPTION VALUES (G/KG/DAY) - SUMMARY
DOSAGE GROUP | I | II | III | IV |
|
DOSAGE (MG/KG/DAY)a |
| 0 (VEHICLE) | 250 | 500 | 1000 |
RATS TESTED | N | 25 | 25 | 25 | 25 |
PREGNANT | N | 22 | 24 | 24 | 25 |
MATERNAL FEED |
|
|
|
|
|
CONSUMPTION (G/KG/DAY) |
|
|
|
| |
DAYS 0 - 7 | MEAN±S.D. | 96.2 ± 6.8 | 94.2 ± 6.9 | 93.5 ± 10.6 | 92.5 ± 6.5 |
|
|
| [ 23]b | [ 23]b |
|
DAYS 7 - 10 | MEAN±S.D. | 58.6 ± 10.2 | 60.8 ± 9.7 | 60.4 ± 12.7 | 46.2 ± 11.3** |
|
|
|
| [ 23]b |
|
DAYS 10 - 12 | MEAN±S.D. | 61.4 ± 9.6 | 65.4 ± 8.8 | 60.0 ± 7.9 | 54.2 ± 15.5* |
DAYS 12 - 15 | MEAN±S.D. | 59.8 ± 7.2 | 63.5 ± 9.7 | 59.6 ± 7.1 | 54.9 ± 9.3 |
|
|
| [ 22]b | [ 23]b |
|
DAYS 15 - 18 | MEAN±S.D. | 63.8 ± 14.0 | 68.7 ± 7.6 | 64.2 ± 10.0 | 60.8 ± 8.9 |
|
| [ 21]b |
|
|
|
DAYS 7 - 18 | MEAN±S.D. | 61.0 ± 5.6 | 64.5 ± 6.0 | 61.4 ± 7.3 | 54.1 ± 6.1** |
|
| [ 21]b |
|
|
|
DAYS 18 - 21 | MEAN±S.D. | 73.1 ± 8.1 | 71.8 ± 8.7 | 74.6 ± 7.1 | 76.2 ± 8.1 |
DAYS 7 - 21 | MEAN±S.D. | 63.7 ± 4.8 | 66.4 ± 5.4 | 64.7 ± 6.0 | 59.6 ± 5.3* |
DAYS 0 - 21 | MEAN±S.D. | 69.5 ± 4.0 | 70.5 ± 4.6 | 69.0 ± 5.3 | 66.0 ± 3.8* |
[ ] = NUMBER OF VALUES AVERAGED
* Significantly different from the vehicle control group value (p≤0.05). ** Significantly different from the vehicle control group value (p≤0.01).
Table 4: Dosage-Dependent Statistically Significant Fetal Observations (Average Ossification Sites per Fetus per Litter)
Observation | Dosage Group (DGs 7 through 17) |
|
| ||
mg/kg/day | 0 (Vehicle) | 250 | 500 | 1000 | Historical Controla |
|
|
|
|
|
|
Litters | 22 | 24 | 24 | 25 | 982 |
Fetuses | 155 | 164 | 183 | 184 | 7305 |
Rats tested, n | 25 | 25 | 25 | 25 |
|
Rats pregnant, n (%) | 22 (88) | 24 (96) | 24 (96) | 25 (100) |
|
|
|
|
|
|
|
Corpora lutea, mean ± SD | 14.6 ± 2.4 | 14.9 ± 2.8 | 16.3 ± 2.4 | 15.8 ± 2.3 |
|
Implantations, mean ± SD | 14.0 ± 2.1 | 13.8 ± 2.8 | 15.2 ± 1.7 | 14.8 ± 1.8 |
|
Resorptions, mean ± SD | 0.6 ± 0.7 | 0.8 ± 0.9 | 0.6 ± 0.6 | 0.5 ± 1.2 |
|
Litter size, mean ± SD | 13.4 ± 2.2 | 13.0 ± 2.4 | 14.6 ± 2.0 | 14.3 ± 2.4 |
|
Fetal body weight/litter, mean ± SD | 5.50 ± 0.28 | 5.54 ± 0.30 | 5.55 ± 0.31 | 5.33 ± 0.33 |
|
Male fetuses | 5.63 ± 0.28 | 5.73 ± 0.31 | 5.68 ± 0.28 | 5.45 ± 0.36 |
|
Female fetuses | 5.38 ± 0.29 | 5.37 ± 0.28 | 5.42 ± 0.35 | 5.18 ± 0.32* |
|
Live fetuses/group | 295 | 311 | 350 | 358 |
|
Dead fetuses/group | 0 | 0 | 0 | 0 |
|
|
|
|
|
|
|
Ribs (pairs)b,c | 13.06 ± 0.11 | 13.06 ± 0.10 | 13.09 ± 0.13 | 13.19 ± 0.23d | 13.06 (13.02-13.12) |
Thoracic Vertebraeb,c | 13.08 ± 0.15 | 13.08 ± 0.16 | 13.12 ± 0.17 | 13.24 ± 0.28*,d | 13.08 (13.02-13.16) |
Lumbar Vertebraeb,c | 5.92 ± 0.15 | 5.91 ± 0.16 | 5.87 ± 0.17 | 5.75 ± 0.27**,d | 5.92 (5.83-5.97) |
Metatarsalsb,c | 4.95 ± 0.12 | 4.87 ± 0.21 | 4.91 ± 0.12 | 4.78 ± 0.27**,d | 4.83 (4.68-4.95) |
|
|
|
|
|
|
* = Significantly different from the vehicle control group value (p≤0.05). ** = Significantly different from the vehicle control group value (p≤0.01).
Testing facility historical control data for mean fetal body weight ranges (82 studies): combined male/female, 4.94 to 5.93 g; male fetuses, 5.10 to 5.98 g; female fetuses, 4.80 to 5.78 g.
Effect on developmental toxicity: via oral route
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- NOAEL
- 1 000 mg/kg bw/day
- Study duration:
- subacute
- Species:
- rat
- Quality of whole database:
- Guideline study with acceptable restrictions
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
Developmental toxicity, rat, RL2
There is no information available on the developmental toxicity of dihydromyrcenol in rats.
Developmental toxicity was determined in rats following the GLP and the ICH Harmonized Tripartite Guidelines (Stages C and D of the reproductive process) with the analogue chemical, dimyrcetol. The test item was administered in corn oil by gavage to groups of pregnant Sprague-Dawley rats at dosages of 0, 250, 500 or 1000 mg/kg bw/day on gestational days 7 to 17. Viability, clinical signs, body weights and feed consumption were observed or measured for all animals. Animals were sacrificed on gestational day 21 and Caesarean sectioning performed. Fetuses were weighed and examined for sex, gross changes, and soft tissue or skeletal alterations. No clinical signs attributable to the test item administration were observed. At the 1000 mg/kg bw/day dose level, mean maternal body weight gains were reduced 5% versus controls. Absolute and relative feed consumption were also reduced at this dose level. The minimal maternal effects noted were associated with minimal (approx. 3%) reductions in fetal body weights, reversible variations in ossification and increases in supernumerary thoracic ribs with associated increases or decreases in thoracic and lumbar vertebrae, respectively. Findings of delayed skeletal ossification are generally considered readily reversible (Carney and Kimmel, 2007 "Interpretation of skeletal variations for human risk assessment: Delayed ossification and wavy ribs", Birth Defects Research 80:473 -496). The minimal developmental delays (reduced pup weights, delayed ossificaiton, changes in metatarsals) are all expected to be readily reversible based on studies that have investigated the progression and outcome of similar effects. On the basis of these data, the maternal no-observable-adverse-effect-level (NOAEL) was 1000 mg/kg bw/day. At this dose level, maternal body weight gains were reduced (not significantly) and feed consumption was significantly reduced. The 500 mg/kg bw/day dose level was assigned as the NOEL for maternal effects.The developmental NOAEL was also 1000 mg/kg bw/day. This was based on minimal reductions in female fetal weights and small increases in reversible variations in skeletal ossification. The 500 mg/kg bw/day dose level was assigned as the NOEL for developmental effects.
Prenatal developmental toxicity study, rabbit
Based on an ECHA decision (decision number TPE-D-2114607166-54-01/F), a Pre-natal developmental toxicity study (PNDT, Annex X, Section 8.7.2.; test method: OECD TG 414) by oral route, in a second species (rabbit) has been requested by ECHA. As no toxicity data in rabbits are available for the substance, a dose-range finding study will be conducted to determine the doses for the main study. The requested OECD TG 414 study in rabbits will be started as soon as possible, depending on the laboratory's capacities and will follow the study design specifications made by ECHA (OECD 414, rabbit, oral route). This section will be updated with the results of the PNDT study as soon as the study is finalized.
Please refer to Section 13 of the IUCLID file for read-across documentation and rationale for the use of analogue chemicals for dihydromyrcenol.
Justification for classification or non-classification
Classification, Labeling, and Packaging Regulation (EC) No 1272/2008
The available experimental test data are reliable but not sufficient for classification purposes according to Regulation (EC) No 1272/2008 (CLP), as amended for the eighteenth time in Regulation (EU) 2022/692.
Additional information
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
