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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
(Test substance was administered from Days 6-15 of gestation; however, guideline recommends dosing from implantation through the entire period of gestation to the day before caesarean section.)
Qualifier:
equivalent or similar to
Guideline:
EPA OPP 83-3 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
(Test substance was administered from Days 6-15 of gestation; however, guideline recommends dosing from implantation through the entire period of gestation to the day before caesarean section.)
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
Test animals:
- Source: Sprague Dawley CD rats (Crl: CD BR) were obtained from Charles River Breeding Laboratories, Portage MI USA.
- Age at study initiation: 11 weeks
- Weight at study initiation: 245.0-246.6 g
- Housing: Animals were housed singly in stainless steel cage, wire mesh caging; dimension, 22.5 x 15.5 x 18.0 cm during the study.
- Diet: Ground Certified Rodent Chow # 5002 (Ralston Purina Company, St. Louis, MO), ad libitum
- Water: Tap water, ad libitum. Water was provided by an automatic watering system with demand control valves mounted on each rack.
- Acclimation period: 2 weeks

Environmental conditions:
- Temperature: 66-77°F
- Humidity: 40-70%
- Air changes: 8/h

In-life dates: From: 14 October 1991 to: 29 November 1991

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Remarks:
(Milli-Q water)
Details on exposure:
Preparations of dosing solutions: Dosing solutions were prepared by dissolving appropriate amount of the test substance with Milli-Q water. Concentrations were adjusted for percent active ingredient of the test substance.
- Rate of dose preparation: Dosing solutions were prepared once.
- Storage of dose formulations: Room temperature

Vehicle
- Concentration in vehicle: 0, 2, 6, and 20 mg/mL
- Amount of vehicle (if gavage): 5 mL/kg bw/day

Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Dose formulations were analysed for concentration, homogeneity and stability by HPLC method.
- The homogeneity study performed on samples from the 10 and 100 mg/kg bw/day concentrations indicated that the test substance was uniformly distributed in the solution.
- The stability study conducted on lowest and highest concentrations indicated that the test substance was stable in the solutions for at least 14d in a glass flask when stored at room temperature.
- Concentration verification analyses of the dosing solutions showed analytical mean values ranging from 94.5 to 104.8% of nominal for all 3 concentrations.
Details on mating procedure:
- Impregnation procedure: Co-housed
- If cohoused: Animals were co-housed in stainless steel wire mesh cages (30.5 x 31.0 x 18.0 cm).
- M/F ratio per cage: 1:1
- Length of cohabitation: Animals were cohoused until evidence of copulation was observed
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility: Each male was paired only once in the study.
- Verification of same strain and source of both sexes: Male and female rats were obtained from same source
- Proof of pregnancy: Presence of vaginal copulation plug. This day was designated as Day 0 of gestation
Duration of treatment / exposure:
From Day 6-15 of gestation
Frequency of treatment:
Once daily during exposure period
Duration of test:
16d (From Day 6 to Day 21 post coitum)
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day
Remarks:
vehicle alone
Dose / conc.:
10 mg/kg bw/day
Dose / conc.:
30 mg/kg bw/day
Dose / conc.:
100 mg/kg bw/day
No. of animals per sex per dose:
25
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The dosages were selected by the study sponsor on the basis of a range finding study with the test substance (BBRC Project Report 54-613).
- Rationale for animal assignment: Immediately after mating the female rats were randomly allocated to treatment groups and control group using a stratified randomization program based on body weight on gestation Day 0.
- Animal assignment: Mated rats were assigned to the following groups.
Group 1 (vehicle control): 0 mg/kg bw/day
Group 2 (Low dose): 10 mg/kg bw/day
Group 3 (Mid dose): 30 mg/kg bw/day
Group 4 (High dose): 100 mg/kg bw/day

Examinations

Maternal examinations:
Mortality: Yes
Time schedule: Twice daily

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: Body weights were recorded on Days 0, 6, 9, 12, 15, 18 and 21.

FOOD CONSUMPTION: Yes
- Time schedule: Food consumption was recorded for every 3 d intervals from Days 0 to 21 post coitum (Days 0-3, 3-6, 6-9, 9-12, 12-15, 15-18 and 18-21)

WATER CONSUMPTION AND COMPOUND INTAKE: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on: Day 21 post coitum
- The females were killed by CO2 asphyxiation and the fetuses removed by caesarean section.
- Organs examined: Gravid uterus, ovaries, cervix, vagina, and peritoneal and thoracic cavities

OTHER: Liver and gravid uterine were weighed.
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
Fetal examinations:
- The fetuses were removed from the uterus, sexed, weighed individually and examined for variations and malformations including cleft palate
- External examinations: Yes (all per litter)
- Soft tissue examinations: Yes (approximately half per litter)
- Skeletal examinations: Yes (approximately half per litter)
- Head examinations: Yes (approximately half per litter)
- Body weight: Yes
Statistics:
- Levene’s test for equal variances, analysis of variance, and a pooled t-tests for pairwise comparisons.
- Nonparametric data were analyzed with Kruskal-Wallis test followed by Mann-Whitney U test when appropriate.
- Incidence data were compared using Fisher’s Exact Test.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Perioral wetness in 67% of dams and audible respiration in 3 dams of high dose group. One dam in this group exhibited dehydration, unkempt appearance, loose feces, urine stains, and perioral wetness. Audible respiration in 2 dams of mid dose group. One of these dams also exhibited urine stains, gasping, perinasal encrustation, loose feces and perioral wetness.



Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
There were no effects of treatment on gestational body weight and body weight gain in any dose group.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Food consumption was reduced between Days 6 to 9 in the mid and high dose group.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
There were no effects of treatment on the gravid uterine weight in any dose group.
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Ulceration of stomach and gas-filled intestines, color changes in liver and lymph nodes and small spleen was seen in one dam of high dose group. Swollen liver was observed in one dam of mid dose group.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Number of abortions:
no effects observed
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:
not examined
Details on maternal toxic effects:
- Maternal toxic effects: Yes
- Developmental toxicity: There were no treatment-related differences in the number of ovarian corpora lutea and in gestational parameters including total number of implantations, number of viable and nonviable implants.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOEL
Remarks:
systemic toxicity
Effect level:
ca. 10 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
gross pathology
other: clinical signs and reduced food consumption
Remarks on result:
other: equivalent to 8.1 mg a.i./kg bw/day

Maternal abnormalities

Key result
Abnormalities:
effects observed, treatment-related
Localisation:
other: general toxicity
Description (incidence and severity):
Clinical signs, food consumption and gross pathological findings

Results (fetuses)

Fetal body weight changes:
no effects observed
Description (incidence and severity):
No treatment-related effects on fetal body weights were observed in any group.
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
not examined
Changes in litter size and weights:
no effects observed
Changes in postnatal survival:
not examined
External malformations:
no effects observed
Description (incidence and severity):
No test substance-related relevant effects during the external examination of fetuses were noted in any group.
Skeletal malformations:
no effects observed
Description (incidence and severity):
No treatment-related variations or malformations.
Visceral malformations:
no effects observed
Description (incidence and severity):
No treatment-related variations or malformations.
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects: No effects

Effect levels (fetuses)

Key result
Dose descriptor:
NOEL
Remarks:
general and developmental toxicity
Effect level:
ca. 100 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no effects observed
Remarks on result:
other: equivalent to 81 mg a.i./kg bw/day

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
Under the study conditions, the NOEL for maternal toxicity and development toxicity was established at 10 and 100 mg a.i./kg bw/day respectively (equivalent to 8.1 and 81 mg a.i./kg bw/day respectively).
Executive summary:

A study was conducted to determine the developmental toxicity and teratogenicity of the test substance, C12-16 ADBAC (81.09% active in aqueous/ethanol solution), according to OECD Guideline 414 and US EPA OPP 93 -3, in compliance with GLP. The experiment was performed in pregnant Sprague-Dawley CD rats. The test substance was administered to groups of 25 pregnant rats orally by gavage at dose levels of 0, 10, 30 and 100 mg/kg bw/day, once daily from Days 6 to 15 of gestation inclusive. Control animals were treated with the vehicle alone (Milli-Q water). Clinical observations were made twice daily, and maternal body weights were measured on gestation Days 0, 6, 9, 12, 15, 18 and 21. Maternal food consumption was measured at 3-day intervals from Day 0 to Day 21. All surviving females were sacrificed on Day 21 and the foetuses were examined for visceral and skeletal variations and malformations. No mortality was observed during the study. Treatment-related clinical signs included perioral wetness and audible respiration (in 3 dams) in high dose group. Audible respiration was also observed in 2 dams in the mid dose group. One of these dams also exhibited urine stains, gasping, perinasal encrustation, loose feces and perioral wetness. Food consumption was reduced between Days 6 to 9 in mid and high dose groups. There were no effects of treatment on gestational body weight and body weight gain and gravid uterine weight in any dose group. There were also no treatment-related differences in gestational parameters including total number of implantations, number of viable and nonviable implants between the control and the test groups. Further, there were no effects of treatment on fetal body weights per litter, or on the incidences of external, visceral and skeletal malformations and variations. Based on the results of the study, administration of the test substance by gavage to pregnant rats resulted in maternal toxicity at 100 mg a.i./kg bw/day. No developmental toxicity including teratogenicity was observed at any dosage employed. Under the study conditions, the NOEL for maternal toxicity and development toxicity was established at 10 and 100 mg a.i./kg bw/day respectively (equivalent to 8.1 and 81 mg a.i./kg bw/day respectively) (Neeper-Bradley, 1992).