Registration Dossier

Administrative data

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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
not specified
Remarks:
The study was not performed under GLP conditions, but a statement of the quality assurance unit of the test facility is included. The generated data are considered reliable and scientifically sound.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
red powder
Batch # : BRA1/315

Test animals

Species:
rat
Strain:
Sprague-Dawley

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: 0.5 % Carboxymethylcellulose (CMC) in water
Analytical verification of doses or concentrations:
no
Details on mating procedure:
successful mating was verified by vaginal smear and/or vaginal plug analysis
Duration of treatment / exposure:
from day 6 to day 15 of gestation
Frequency of treatment:
once daily
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (actual dose received)
Remarks:
control group
Dose / conc.:
10 mg/kg bw/day (actual dose received)
Dose / conc.:
30 mg/kg bw/day (actual dose received)
Dose / conc.:
60 mg/kg bw/day (actual dose received)
No. of animals per sex per dose:
24
Control animals:
yes, concurrent vehicle

Examinations

Maternal examinations:
Animals were observed at least once daily for clinical signs during the entire treatment period. Body weights were recorded at days 0, 6 11, 16 and 20 of gestation. Food consumption was measured for the intervals day 0-6, 6-11, 11-16 and 16-20 and calculated for the entire study period (0-20).
Ovaries and uterine content:
The ovaries and the intact uterus (prepared by caesarean sections) were removed and the presence of resorption sites (early, late) and foetuses (live or dead and birth position) were examined. The number of implantation sites and of corpora lutea were also determined. In addition placenta weights were recorded.
Fetal examinations:
Each live foetus was weighed, sexed and examined for gross external malformations. After fixation and staining a skeletal and a visceral examination of the foetuses was performed on 50% of the foetuses each.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Clinical biochemistry findings:
no effects observed
Gross pathological findings:
no effects observed
Other effects:
no effects observed

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 number of pregnant:
no effects observed

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
60 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: highest dose tested

Results (fetuses)

Fetal body weight changes:
no effects observed
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
External malformations:
no effects observed
Skeletal malformations:
no effects observed
Visceral malformations:
no effects observed

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
60 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: highest dose tested

Overall developmental toxicity

Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
No adverse effects were noted in dams or for the foetal development up to the highest test dose administered in this rat teratogenicity study. Consequently, a NOAEL of 60 mg/kg bw/day for both the parental and the developmental toxicity of Hydroxyethyl-2-nitro-p-toluidine is deduced from this study. Based on these findings one can conclude that Hydroxyethyl-2-nitro-p-toluidine, at the investigated doses, does not acts as a developmental toxin.
Executive summary:

Hydroxyethyl-2-nitro-p-toluidine, in a constant volume of 10 ml/kg bw (0.5% CMC as vehicle), was administered once daily by oral gavage to groups of 24 pregnant (successful mating was verified by vaginal smear and/or vaginal plug analysis) Sprague Dawley Him:OFA rats at doses of 10, 30 and 60 mg/kg bw/day from day 6 to day 15 of gestation. A concurrent control group received the vehicle (0.5 % CMC) alone. Animals were observed at least once daily for clinical signs during the entire treatment period. Body weights were recorded at days 0, 6 11, 16 and 20 of gestation. Food consumption was measured for the intervals day 0-6, 6-11, 11-16 and 16-20 and calculated for the entire study period (0-20). On day 20 of gestation, all mated females were killed under deep CO2-anesthesia by exsanguination from the thoracid aorta and a complete autopsy and a macroscopic examination of the organs was carried out. The ovaries and the intact uterus (prepared by caesarean sections) were removed and the presence of resorption sites (early, late) and foetuses (live or dead and birth position) were examined. The number of implantation sites and of corpora lutea were also determined. Each live foetus was weighed, sexed and examined for gross external malformations. After fixation and staining a skeletal and a visceral examination of the foetuses was performed on 50% of the foetuses each. In addition placenta weights were recorded. Stability, homogeneity and concentrations of the solutions of Hydroxyethyl-2-nitro-p-toluidine in the vehicle were not analytically confirmed. However, the suitability of this vehicle has been demonstrated already in other studies. No treatment-related effects in dams were noted with regard to clinical observations and post-mortem findings. The body weight, body weight gain and the food consumption were not affected by the treatment with Hydroxyethyl-2-nitro-p-toluidine. Gross necropsy revealed no treatment-related effects. The placenta weights, the number of corpora lutea, and the number of implantations were similar to control values in all treated groups. There were no treatment-related effects with regard to litter size, foetal mortality, foetal body weight, birth position and sex ratio. The skeletal and visceral examination of the foetuses revealed no treatment-related findings. Neither a statistically significant difference nor a dose-dependent increase in any malformation was noted. The observed variations represented common findings for the rat strain used and were within the spontaneous variation range and/or revealed no dose-response relation.