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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions (15 dams per group instead of 20, administration on day 0-19 of gestation, limited details on study design)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
(only 15 presumed pregnant females per group, exposure on day 0-19 of gestation, only 2 dose levels, nonstandard dermal exposure, limited details on exposure)
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Kingston, N.Y.
- Age at study initiation: approx. 9 weeks
- Mean weight at study initiation: 248 g
- Diet: Purina Certified Rodent Chow #5002 (Meal), ad libitum
- Water: tap water, ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 22
- Humidity (%): 40 - 60
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
dermal
Vehicle:
unchanged (no vehicle)
Details on exposure:
TEST SITE
- Type of wrap if used: open exposure, no wrap
- Time intervals for shavings or clipplings: no data on frequency; clipped, intact skin
- Site: dorsal
Controls: The rats of the control group were clipped and collared. The intact dorsal skin of each rat was stroked with the tip of a syringe, but no test material was applied.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): The amount of the test material applied with a syringe was calculated based on the body weight of the animals and the density of the test substance.

USE OF RESTRAINERS FOR PREVENTING INGESTION: yes. To minimize ingestion of the test material, the rats were fitted with cardboard Elizabethan-style collars.
Analytical verification of doses or concentrations:
no
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused: M/F ratio per cage: 1/1
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy
Duration of treatment / exposure:
gestation days 0 - 19
Frequency of treatment:
daily
Duration of test:
The animals were sacrificed on day 20 of gestation.
Doses / concentrations
Remarks:
Doses / Concentrations:
800 and 2000 mg/kg bw/day
Basis:
nominal conc.
No. of animals per sex per dose:
15 presumed-pregnant females
Control animals:
yes, concurrent no treatment
Details on study design:
- Dose selection rationale: based on results of a 13-week dermal study previously conducted with the same material

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least once daily
- Cage side observations checked: signs of pathosis, abortion, premature delivery, and death

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: day 0, 3, 6, 10, 13, 16, and 20 of gestation

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: Yes
- Time schedule for calculation: days 0-3, 3-6, 6-10, 10-13, 13-16, and 16-20

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: The thoracic and abdominal cavities were exposed and all organs were examined grossly for evidence of pathosis.

OTHER:
- Clinical chemistry: alanine aminotransferase (ALT), albumin, albumin/globulin ration, alkaline phosphatase (ALP), aspartate aminotransferase (AST), bilirubin, calcium, chloride, cholesterol, creatinine, globuline, glucose, iron, lactate dehydrogenase (LDH), phosphorus, potassium, sodium, sorbitol dehydrogenase (SDH), total protein, triglycerides, urea nitrogen, and uric acid
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
- Number of live and dead fetuses: Yes
- Other: The ovaries of non-pregnant females were grossly examined and then discarded.
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No
Statistics:
- Analysis of variances and group comparison using Fisher's Exact or Dunnett's test (maternal biophase and cesarean section data, and fetal data)
- ANOVA and Fisher's Exact test (fetal skeletal data)
- Fisher's Exact test (fetal visceral data)
- SAS procdures, Student-Newman-Keul's multiple comparison test (clinical chemistry data)
P < 0.05

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes. Remark: slight local effects

Details on maternal toxic effects:
- General observations: neck lesions, red nasal exudate, and chromodacryorrhea in all groups (considered not to be test substance-related as these signs are common in animals that are collared)
- Local effects: mild dermal irritation including erythema and flaking of the skin in the treatment groups
- Body weight: similar to controls in both treatment groups
- Body weight gain: similar to controls in both treatment groups
- Uterine and net body weights: similar to controls in both treatment groups
- Food consumption: similar to control in both treatment groups; only difference (statistically significant) in high dose group on day 13-16: 31.5 g vs. 29.5 g (corresponding control data)
- Necropsy: no remarkable findings were observed
- Fetal status and uterine position: no parameter evaluated appeared to be adversly affected
- Clinical chemistry: no differences between treated and non-treated rats were observed

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Remarks:
systemic
Effect level:
2 000 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
- Fetal body measurements: Mean fetal body weights and crown-rump lengths, parameters of body growth and development were normal compared to controls.
- Fetal examination: No malformations or variations were observeed. Bruises were observed on the skin of 4 fetuses from the control group and 2 fetuses form the 800 mg/kg bw/day group (considered to be incidental). One fetus from one dam exposed to 800 mg/kg bw/day was pale in colour. No other remarkable findings were observed during external examination.
- Malformations (lumbar and sacral vertebrae, tail, sternebrae, and ribs) were observed. The incidence was low and there was no apparent dose-response relationship, these effects were considered to be not treatment-related. Comparable incidences of variant skeletal development were observed in both cotnrol and trated fetuses.
- Visceral examinations: A statistically significant (high dose) increase in the number of fetuses with levocardia was observed. The response appeared to be dose-related
Levocardia:
Litters: control: 0 (0%); 800 mg/kg bw/day: 2 (14.3%); 2000 mg/kg bw/day: 7 (50%); 14 litters per group examined
Fetuses: control: 0 (0%); 800 mg/kg bw/day: 3 (3.2%); 2000 mg/kg bw/day: 7 (10.1%); 94, 93, and 99 fetuses examined, respectively
Microphthalmia, anophtalmia and "apparent" hydronephrosis were also observed. Variant visceral development was observed in control and treated fetuses.

Effect levels (fetuses)

open allclose all
Key result
Dose descriptor:
LOAEL
Effect level:
800 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
not specified
Basis for effect level:
visceral malformations
Key result
Dose descriptor:
NOAEL
Effect level:
< 800 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
not specified
Basis for effect level:
other: developmental toxicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Levocardia was the only parameter affected in fetuses of dams treated with the test substance during gestation. In other studies, levocardia was observed in control fetuses, too. However, the effect of the test substance on heart development should be focused on in further studies as well as the impact, this effect has on postnatal survival.

Applicant's summary and conclusion

Conclusions:
In a developmental toxicity study, pregnant rats were dermally exposed to the test substance. No adverse effects were observed in any maternal or reproductive parameter nor on external and skeletal development of fetuses. Levocardia was observed in 3.2% and 10.1% of the fetuses exposed in utero to 800 and 2000 mg/kg bw /day, respectively. Thus, the developmental NOAEL was determined to be < 800 mg/kg bw.