2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2-methylphenyl)-3-oxobutyramide]

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 26 JUL 2000 to 02 OCT 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline study (OECD TG 422)

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]

EC Number:

228-787-8

EC Name:

2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]

Cas Number:

6358-85-6

Molecular formula:

C32H26Cl2N6O4

IUPAC Name:

2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide)

Test material form:

solid: nanoform

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- strain: Wistar Crl:(WI) BR (outbred, SPF)
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: approximately 14 weeks
- Weight at study initiation: group means males: 489-501 g; group means females: 267-271 g
- Fasting period before study: no
- Housing:
acclimatisation period: 5 animals per sex per cage, stainless steel suspended cages with wire mesh floors
mating period: 1 female together with 1 male, stainless steel suspended cages with wire mesh floors
after mating: animals were housed individually, Macrolon cages (Type III)
- Diet: standard pelleted laboratory animal diet (Carfil Quality BVBA, Oud-Turnhout, Belgium), ad libitum
- Water: tap water, ad libitum
- Acclimation period: 26 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 +/- 3
- Humidity (%): 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: polyethylene glycol 400

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
- formulations (w/w) were prepared daily within 4 hours prior to dosing
- storage at ambient temperature

VEHICLE
- vehicle: polyethylene glycol 400, specific gravity: 1.125
- Justification for use and choice of vehicle: based on trial fromulations
- Concentration in vehicle: 0 mg/g; 4.45 mg/g; 17.8 mg/g; 89.9 mg/g
- Amount of vehicle: 10 ml/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical study was performed to check accuracy of preparation and to determine stability and homogeneity of test substance preparation.
Test samples were dissolved in chloroform by sonication and analysed spectrophotometrically.

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: up to 14 days
- Proof of pregnancy: copulation plugs in the cage, sperm in vaginal smear referred to as day 0 of pregnancy
- After 14 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged: individually
- Any other deviations from standard protocol: no

Duration of treatment / exposure:

F0-males:
- for 2 weeks prior to mating, throughout mating and after mating at least until the minimum total dosing period of 28 days had been completed
F0-females:
2 weeks prior to mating, throughout mating, and pregnancy and at least up to, and including the day before sacrifice

Frequency of treatment:

once daily

Duration of test:

Start treatment: 2000-08-21
Start terminal procedures: F0-males: 2000-09-19; F0-females: 2000-10-02

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

50 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

200 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on the results of a dose range finding study with the test item (5 days oral exposure of male and female rats to 50, 200 and 1000 mg/kg bw/day did not cause changes in clinical appearance, body weights, food consumption, macroscopic examination and organ weights)

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily in the home cage and twice during the complete study in a standard arena


BODY WEIGHT: Yes
- Time schedule for examinations:
F0-females: on the first day of dosing and weekly thereafter
mated femaes were weighed daily from day 0 until day 20 of gestation inclusive
F0-females were weighed daily during lactation


FOOD CONSUMPTION: Yes
- Time schedule for examinations: weekly, but not during the mating period


WATER CONSUMPTION: Yes
- Time schedule for examinations: subjective appraisal during the study, no quantitative investigation


OTHER:
Observations on haematology, clinical chemistry and neurobehavioural examination are reported in section 7.5.1

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: No data
- Number of late resorptions: No data

Fetal examinations:

- The number and sex (by assessment of the ano-congenital distance) of pups, of stillbirths,
of live births, and of runts within 24 hours of parturition (day 0 or 1 post partum)
- The number en sex of live pups an day 4 post partum
- The weight of all litters within 24 hours of parturition and an day 4 post partum
- The number of pups with physical or behavioural abnormalities (daily)
- The number of pups with externally visible macroscopic abnormalities (daily)

Statistics:

- Dunnett-test
- Steel-test
- exact Fisher-test

Indices:

Reproductive indices:
- percentage mating: (number of females mated)/(number of females paired) * 100
- fertility index: (number of animals pregnant or siring a litter)/(number of females paired) * 100
- conception index: (number of animals pregnant)/(number of females mated) *100
- gestation index: (number bearing live pups)/(number pregnant) * 100


Offspring viability indices:
- percentage live males at first litter check: (number of live male pups)/(number of live pups) * 100
- percentage live females at first litter check: (number of live female pups)/(number of live pups) * 100
- viability index: (number of live pups on day 4 P.P.)/(number of live pups born alive) * 100

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
No treatment related clinical signs were observed (see section 7.5.1).

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Body weights and body weight gain of treated animals remained in the same range as controls (see section 7.5.1).


TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
There were no differences in food consumption (absolute and relative) between treated and control animals (see section 7.5.1).

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
Four females (one female in each group) were non-pregnant.

The average number of implantation sites in pregnant females receiving 50, 200 or 1000 mg/kg/day was 13.7, 16.3 and 15.2, respectively, compared with a mean figure of 14.7 for the control group. These values are within the range expected in control rats of this age and strain, and give no indication of a treatment-related disturbance.

The majority of pairs mated during the first 4 days of the mating period. Mean pre-coital times were similar for treated and control groups.

For each dose group, 100% mating was confirmed. The fertility and conception indices were similar for treated and control groups. The gestation Index was 100% for all treatment groups.


ORGAN WEIGHTS (PARENTAL ANIMALS)
Organ weights and organ:body weight ratlos of treated animals were considered to be similar to those of control animals.


GROSS PATHOLOGY (PARENTAL ANIMALS)
Macroscopic observations of the remaining animals at necropsy did not reveal any alterations that were considered to have arisen as a result of treatment.


HISTOPATHOLOGY (PARENTAL ANIMALS)
There were no microscopic findings recorded which could be attributed to treatment with the test substance.

OTHER FINDINGS:

BREEDING DATA:
The mean duration of gestation of treated females was similar to that of the control females and ranged between 21.4 and 22.0 days.

Effect levels (maternal animals)

1

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: maternal toxicity

2

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: developmental toxicity

Maternal abnormalities

Key result

Abnormalities:

no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
VIABILITY (OFFSPRING)
The number of living and dead pups at first litter check revealed similar values for treated and control groups. Postnatal loss between days 0-4 post partum showed a statistical significant increase in the 50 mg/kg dose group. Consequently, the viability Index of this group was statistical significant decreased. This was considered to be caused mainly by the loss of one litter, therefore no toxicological significance was attached to this finding.

CLINICAL SIGNS (OFFSPRING)
No unexpected clinical signs were recorded among pups of any dose group. The incidences of the small number of findings were within expected limits and showed no relationship to dose. They included no milk in stomach, hypothermia, smell appearance, open skull and back, curled tail, prothrusion of the tongue, autolytic pup, yellow skin, haemorrhage on stomach, and broken tail.

BODY WEIGHT (OFFSPRING)
No statistically significant group differences were recorded for body weights of pups at days 1 and 4 post partum.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no changes in examined parameters observed

Fetal abnormalities

Key result

Abnormalities:

no effects observed

Overall developmental toxicity

Key result

Developmental effects observed:

no

Applicant's summary and conclusion

Conclusions:

There were no changes in clinical appearance, functional observations, body weights, food consumption, clinical laboratory investigations, reproduction, litter observation, macroscopic examination, organ weights and microscopic examination that were considered to be an effect of treatment.
From the results presented in this report a definitive No Observed Adverse Effect Level (NOAEL) for parental and reproduction/developmental toxicity for the test item of 1000 mg/kg/day was established.

Executive summary:

A combined repeated dose toxicity study with reproduction/developmental toxicity screening test with the test item administered by oral gavage in Wistar rats (10/sex/dose) was performed according to OECD TG 422. The dose levels for this study were 0, 50, 200 and 1000 mg/kg bw/day. Oral dosing of male and fernale Wistar rats with the test item at dose levels of 50, 200 or 1000 mg/kg b.w./day for at least 28 days, revealed no treatment-related findings on parental animals, on fertility, on embryo-foetal development, or on pup development. From the results presented in this report a definitive No Observed Adverse Effect Level (NOAEL) for parental and reproduction/developmental toxicity for the test item of 1000 mg/kg/day was established.