1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic anhydride

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 13 February 1978 to 10 March 1978

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:

1978

Report date:

1978

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.31 (Prenatal Developmental Toxicity Study)

Deviations:

not specified

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic anhydride

EC Number:

204-077-3

EC Name:

1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic anhydride

Cas Number:

115-27-5

Molecular formula:

C9H2Cl6O3

IUPAC Name:

1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic anhydride

Details on test material:

- Name of test material (as cited in study report): Chlorendic anhydride- Physical state: White powder- Analytical purity: 93.81%- Impurities (identity and concentrations): Chlorendic acid 4.31% Maleic anhydride 0.40%- Purity test date: 16 Aug 77- Lot/batch No.: 3-12-206

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Canada.
- Age at study initiation: 3 months
- Housing: Individual in wire-mesh cages.
- Diet: Purina Laboratory Chow, ad libitum
- Water: ad libitum
- Acclimation period: 10 days minimum.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Chlorendic Anhydride was suspended using a tissue homogenizer in Mazola corn oil at varying concentrations to permit the administration of 10 ml / kg / day at dosage levels of 25, 100 and 400 mg / kg / day.


DIET PREPARATION
- Rate of preparation of diet (frequency):
- Mixing appropriate amounts with (Type of food):
- Storage temperature of food:


VEHICLE
- Justification for use and choice of vehicle (if other than water): Corn oil
- Concentration in vehicle:
- Amount of vehicle (if gavage):
- Lot/batch no. (if required):
- Purity:

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:1
- Length of cohabitation: The day of mating was determined by daily inspection for a copulatory plug or vaginal smear for sperm.
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: [no / yes (explain)]
- Verification of same strain and source of both sexes: [yes / no (explain)]
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy
- Any other deviations from standard protocol:

Duration of treatment / exposure:

From day 6 to day 15 of gestation.

Frequency of treatment:

Daily

Duration of test:

20 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

25 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

400 mg/kg bw/day (nominal)

No. of animals per sex per dose:

25

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
- Cage side observations checked in table [No.?] were included.


DETAILED CLINICAL OBSERVATIONS: No
- Time schedule:


BODY WEIGHT: No
- Time schedule for examinations:


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes / No / No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No
- Time schedule for examinations:


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: The number and location of viable and non-viable fetuses early and late resorptions total implantations and corpora lutea were recorded The sex and body weight were recorded for each fetus.


OTHER:

Ovaries and uterine content:

The uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: No
- Number of implantations: No
- Number of early resorptions: No
- Number of late resorptions: No
- Other: Fetal malformations and genetic variations;

Malformations; Cleft lip with other head anomaly, Bent ribs, Adrenals absent, Supernumerary digit

Developmental and genetic variations; 12 full pair of ribs, 27 presacral vertebrae, 14th full rib(s), 14th rudimentary rib(s), 7th cervical rib(s), Sternebrae no 5 and/or no. 6 unossified, Other sternebrae unossified, Misaligned sternebrae, Reduced ossification of skull, Hyoid unossified, Renal papilla not developed witn/ orwithout ureters distended

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: Yes:all per litter
- Head examinations: Yes: all per litter

Statistics:

All statistical analyses compared the treatment groups with the control group with the level of significance at p < 0.05. Male to
female fetal sex ratio number of litters with anomalies and number of fetuses with anomalies were compared using the Chi square test criterion with Yates correction for 2 x 2 contingency tables and / or Fisher s exact probability test as described by Siegel to judge
significance of differences. The proportion of early and late resorbed fetuses, non-viable fetuses and post-implantation losses were compared by the Mann Whitney U-test as described by Siegel and Weil to judge significance of differences.
Mean number of corpora lutea total implantations and viable fetuses were compared by analysis of variance (one-way classification) Bartlett's test for homogeneity of variances and the appropriate t-test (for equal or unequal variances) as described by Steel and Torrie using Dunnett's multiple comparison table to judge significance of differences.
Fetal body weights were compared by analysis of variance (hierarchal classification) and t-test as described by Steel and Torrie using Dunnett's multiple comparison tables to judge significance of differences.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yesDetails on maternal toxic effects:No animals died during the study but some showed weight loss at the highest dose.

Effect levels (maternal animals)

Dose descriptor:

NOEL

Effect level:

100 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 effectsDetails on embryotoxic / teratogenic effects:There were no malformed fetuses in the control group, one malformed fetus in the 25 mg / kg / day group, 2 malformed fetuses in two litters in the 100 mg / kg / day group and 1 malformed fetus in the 400 mg / kg / day group. These malformations were not statistically significant and not considered to be treatment related. The variations observed were similar for all groups.

Effect levels (fetuses)

Dose descriptor:

NOEL

Effect level:

<= 400 mg/kg bw/day (actual dose received)

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Chlorendic Anhydride groups were not biologically meaningful when compared to the control group. Chlorendic Anhydride is not considered teratogenic in rats in dosage levels up to and including 400 mg / kg / day.

Executive summary:

Pregnant Charles River CD rats were used to evaluate the teratogenic potential of Chlorendic Anhydride in a study performed according to a method similar to EU Method B.31 (non GLP). The compound was administered by gastric intubation at dosage levels of 25, 100 and 400 mg/kg/day from days 6 through 15 of gestation. A control group received the vehicle corn oil at 10 ml/kg/day. During gestation the females were observed for clinical signs of effect for mortality and for changes in body weight gains. Cesarean sections were performed on gestation day 20. The number of viable and nonviable fetuses early and late resorptions corpora lutea and total implantations were recorded. The fetuses were weighed sexed and examined for external soft tissue and skeletal anomalies and variations. There were no differences in maternal body weights or changes in appearance or behavior for rats in the 25 or 100 mg/kg/day dosage group when compared to the control group. There was a slight increase in matted fur red nasal discharge and anogenital staining in the 400 mg/kg/day dosage group when compared to the control group. A slight mean body weight loss during the first 3 days of treatment and reduced mean body weight gains throughout treatment were seen for the rats in the 400 mg/kg/day dosage group when compared to the control group. Survival was 100% for all groups. There were no biologically meaningful differences in the mean number of viable fetuses total implantations corpora lutea or male to female sex ratio in any of the Chlorendic Anhydride treated groups when compared to the control group. There was an increase in the mean number of postimplantation losses in the 100 and 400 mg/kg/day dosage groups when compared to the control group however this increase was only slightly higher than the historical control mean. The number of developmental or genetic variations were comparable for all Chlorendic Anhydride dosage groups and the control group. The increase in malformations in the Chlorendic Anhydride groups were not biologically meaningful when compared to the control group. Chlorendic Anhydride is not considered teratogenic in rats in dosage levels up to and including 400 mg/kg/day.