Tetrachlorophthalic anhydride

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Tetrachlorophthalic anhydride

EC Number:

204-171-4

EC Name:

Tetrachlorophthalic anhydride

Cas Number:

117-08-8

Molecular formula:

C8Cl4O3

IUPAC Name:

tetrachloro-1,3-dihydro-2-benzofuran-1,3-dione

Details on test material:

- Name of test material (as cited in study report): Tetrachlorophthalic anhydride
- Physical state: white solid flake
- Analytical purity: 98.5%
- Stability under test conditions: At least two years from date of manufacture (Lot DA-60 manufactured April 2, 1981)
- Storage condition of test material: closed container at room temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: females 60 days old (sexually mature, virgin); males (sexually mature)
- Housing: single
- Diet (e.g. ad libitum): Purina Rat Chow 5002
- Water (e.g. ad libitum): tap water

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Appropriate amounts of test article were suspended in corn oil. The test material / corn oil suspensions were prepared fresh weekly. When not in use, dosing suspensions were refrigerated. In formulating dosing suspensions, the amount of test material added was corrected for active ingredient. Animals were dosed at a constant volume of 10 ml/kg bw.

Analytical verification of doses or concentrations:

yes

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:2
- Length of cohabitation: one night
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

day 6 to 19 of gestation

Frequency of treatment:

daily

Duration of test:

20 days

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 250, 1000, and 2000 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

24

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: A pilot study was conducted to evaluate the toxicity of the test substance in the pregnant rat. Test material was administered by gastric intubation in corn oil to mated female rats (5/ group) during 6-19 gestation interval. Dose levels were 0, 250, 500, 1000, 1750 and 2500 mg/kg bw/day. Females were sacrificed on day 20 of gestation and uterine implantation data evaluated. Accidental death of 1 rat in the 1000 mg/kg bw dose group and 2 rats in the 2500 mg/kg bw dose group occurred during the study. No clear dose-related effect of treatment on mean body weight change during day 6-20 of gestation interval was evident. Physical evaluation revealed yellowish staining of the fur in the ano-genital region and soft stool in several females at the higher dose levels (1750 and 2500 mg/kg bw). No treatment effects were evident in regards to uterine implantation data or maternal gross postmortem findings. Fetal evaluation indicated a slight but consistent reduction in mean weight (both sexes) at the 2500 mg/kg bw dose level. External evaluation recovered at all treated levels did not reveal an increase in malformations.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: days 0, 6, 10, 15 and 20 of gestation


BODY WEIGHT: Yes
- Time schedule for examinations: says 0, 6, 15 and 20 of gestation


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: reproductive system

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: [all per litter ]
- Soft tissue examinations: Yes: [half per litter ]
- Skeletal examinations: Yes: [half per litter ]

Statistics:

For interval data (body wts, wt changes, reproductive data) -Bartlett's test was used to determine equality of variance and ANOVA and Dunnett's test used for parametric data while the Kruskal-Wallis test and Summed Rank test (Dunn) was used for nonparametric data (Snedecor and Cochran.; Hollander and Wolfe). For Incidence data i.e. mortality rates, % and incidence of variations and malformations -comparisons were made using the Chi-square contingency table and the 2x 2 Fisher Exact test using the Bonferroni inequality estimate; linear trend was evaluated using the Armitage test. Comparisons were made using the litter as the comparative entity. Both the 5% and 10% level of statistical significance were reported for each parameter.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Details on maternal toxic effects:
Mortality: One female in each of the low and mid dosage groups and two females in the high dosage group died during the study, but were considered dosing error and not toxicity-related.
Clinical observation: Physical observations recorded included a lethargic appearance in several mid and high-dosage animals and pale eye color on day 20 of gestation in 4 rats in the 2000 mg/kg bw dose group.
Body weight: Mean body weight gains in animals treated with the test article were comparable to controls.
Pregnancy rate: Pregnancy rates for the control, low-, mid- and high-dose groups were 95.8 % (23/24), 91.7 % (22/24), 100 % (24/24) and 95.8 % (23/24), respectively.
Corpora Lutea and Uterine Implantation Data: mean numbers of corpora lutea and implantations sites were similar to control values. The mean number of resorption sites and the mean percentage of resorptions to implants were considered comparable between control and treated groups. The mean number of live fetuses and the mean percentage of live fetuses to implants were comparable between the control and treated groups.
Postmortem examination: No treatment-related gross pathologic findings were seen at autopsy.

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Details on embryotoxic / teratogenic effects:
Fetal body weight: Mean fetal weights (both sexes) were considered comparable between the control, low- and mid- dose groups. Fetal body weights in the high dose group were significantly depressed in male (- 7%) and female (-8 %) pups when compared to controls. No treatment related effects were evident in fetal sexing data.
Ossification Variation: The types and incidences of ossification variations were comparable between the low, mid and control groups. In the high dose group, a slight increase in the incidence of asymetric/unossified sternebra and incompletely ossified thoracic vertebral centra were observed and are considered representative of a fetotoxic effect.
Fetal external and soft tissue examination: The incidence of external and soft tissue anomalies among treated groups was similar to controls both on a per fetus and per litter basis.
Fetal skeletal examination: The incidence of skeletal malformations was comparable between the control, low and mid dosage groups. The incidence of fetuses with skeletal malformations and the incidence of litters containing an affected fetus for the high-dose group were higher than control, however these differences were not statistically significant. Rib malformations, exclusive of wavy ribs were seen in 3 of the 153 high dose fetuses (an incidence of 2 %). No similar rib malformations were seen in the 159 control, 150 low-dose and 154 mid-dose fetuses evaluated. Total incidence for the control, low, mid and high dose groups were 1.9%, 1.3, 1.3 and 4.6%, respectively.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Summary of malformation data

Dose groups (mg/kg bw)	Malformation	Fetuses		Litters
		No.^a	%	No.^b	%
0	Wavy ribs (bilateral)	3/159	1.9	1/23	4.3
250	Wavy ribs - alone	1/150	0.7	1/21	4.8
	Wavy ribs - with angulated ribs	1/150	0.7	1/21	4.8
	Total	2/150	1.3	2/21	9.5
1000	Hindlimb- digits shortened (unilateral)	1/154	0.6	1/22	4.5
	Cervical vertebral defect	1/154	0.6	1/22	4.5
	Total	2/154	1.3	2/22	9.1
2000	Wavy ribs (bilateral)	2/153	1.3	2/21	9.5
	Fused ribs and vertebral defect	1/153	0.7	1/21	4.8
	Vertebral defects – fused vertebral transverse processes	1/153	0.7	1/21	4.8
	Cervical vertebral transverse process fused to exoccipital	1/153	0.7	1/21	4.8
	Additional rib-like structures	2/153	1.3	1/21	4.8
	Total^c	7/153	4.6	5/21	23.8

No statistically significant differences from control.

^aNo. of fetuses with a malformation/No. of fetuses examined per group

^bNo. of litters containing fetuses with a malformation/ No. of litters evaluated.

^cThe total number of litters containing affected fetuses may not represent the sum of litters containing fetuses with individual malformations in that some litters contained more than one malformed fetus.