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

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

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:

other: 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:

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

IUPAC Name:

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

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

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 oral 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.

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

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 50, 200, 1000 mg/kg bw/day
Basis:
actual ingested

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)

Positive control:

none

Examinations

Observations and examinations performed and frequency:

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-males and F0-females: on the first day of dosing and weekly thereafter
mated females were weighed daily from day 0 until day 20 of gestation inclusive
F0-females were weighed daily during lactation
F1-pubs were weighed on day 1 and 4 post partum


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


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: just prior to killing
- Anaesthetic used for blood collection: Yes (ether anaesthesia)
- Animals fasted: Yes (overnight with a maximum of 20 hours)
- How many animals: 5 males and 5 females randomly selected from each group
- Parameters: erythrocyte count, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelet count, red cell distribution width, total leucocyte count, differential leucocyte count, prothrombin time, partial thromboplastin time


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: just prior to killing
- Animals fasted: Yes (overnight with a maximum of 20 hours)
- How many animals: 5 males and 5 females randomly selected from each group
- Parameters: alanine aminotransferase, aspartate aminotransferase, total bilirubin, total cholesterol, triglycerides, creatinine, glucose, urea, total protein, albumin, globulin, albumin globulin ratio, alkaline phosphatase, sodium, potassium, chloride, calcium, phosphorus


URINALYSIS: No


NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: once, males during week 4 of treatment, femals during lactation (all before blood sampling)
- Dose groups that were examined: all dose groups
- Battery of functions tested: hearing ability / pupillary reflex / static righting reflex / grip strength / motor activity


OTHER:
Observations on females and litters, calculation of reproduction parameters are reported in section 7.8.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (cranial, thoracic, abdominal tissues and organs with special attention to the reproductive organs)
HISTOPATHOLOGY: Yes
from all animals:
accessory sex organs
epididymides (fixed in Bouin's fixative)
ovaries
testes (fixed in Bouin's fixative)
all macroscopic lesions

from 5 animals/sex/group:
adrenal glands
bone marrow
brain
cervix
heart
kidneys
liver
lung, infused with formalin
lymph nodes - mandibular, mesenteric
oesophagus
sciatic nerve
small and large intestines (including Peyer's patches)
spinal cord -cervical, midthoracic, lumbar
spleen
stomach
thymus
thyroid including parathyroid
trachea
urinary bladder
uterus
vagina
all gross lesions

Other examinations:

ORGAN WEIGHTS
- from all males: epididymides, testes
- from 5 animals/sex/group: adrenal glands, brain, heart, kidneys, liver, spleen, thymus

Statistics:

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

Results and discussion

Results of examinations

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

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY
No treatment related clinical signs were observed.

Almost all animals of the control and treated groups showed scabbing, red/brown staining of various body parts, and diarrhoea. Erythema of the anus was seen in all males during the last three weeks of the study period, and piloerection was observed in almost all females. The vehicle (polyethylene glycol) that was used, is known to cause these effects. Therefore, these findings were considered to be of no toxicological significance.
Almost all animals showed alopecia of various parts of the body. Alopecia is commonly seen in group housed rats and therefore no toxicological significance was attached to this finding. Greenish/yellowish faeces and yellow staining of various body parts were observed in almost all animals of the treated groups. This was probably due to the staining properties of the test substance.
Incidental findings included lethargy, rales, hunched posture, laboured respiration, piloerection and reddish faeces in males, chromodacryorrhoea, salivation, and emaciation and are commonly.

One male receiving 200 mg/kg was killed in extremis after showing severe clinical signs. Two males (one of the control and one of the 50 mg/kg dose group) died spontaneously. These three deaths were considered to be unrelated to treatment, because there were no macroscopic findings suggesting a relation with treatment and there were no other death among the animals. No unscheduled deaths occurred among the females.


BODY WEIGHT AND WEIGHT GAIN
Body weights and body weight gain of treated animals remained in the same range as controls.

Except on day 8 of the pre-mating period, when the males of the treatment groups showed a statistical significant reduction in body weight gain when compared to the control group. And on days 2 and 3 of lactation, when females of the 50 mg/kg dose group showed a statistical significant reduced body weight gain. These incidental reductions were considered to have arisen by chance and not to represent a change of toxicological significance.


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
There were no differences in food consumption (absolute and relative) between treated and control animals.

Except on days 2-3 of lactation, when females of the 50 mg/kg dose group showed a statistical significant reduced food consumption (absolute and relative) when compared to the control group. This incidental difference showed no dose relationship and was considered to has arisen by chance and to be of no toxicological relevance.

HAEMATOLOGY
The haematological profile was not disturbed by treatment.

Statistically significant differences for Erythrocyte counts (RBC) of males and females in group 2 (50 mg/kg) did not form a dose response relationship. Therefore, this finding was considered to be of no toxicological relevance.
Monocyte counts were statistically significant decreased in males of group 3 (200 mg/kg). Haemoglobin (HB), haematocrit (HCT), and mean corpuscular haernagiobin (MCHC) values of females in group 2 were statistically significant increased when compared to that of the controls. However, similar findings in the opposite sex were absent and no dose relationship was observed. Therefore, the toxicological significance of these findings was considered to be doubted.


CLINICAL CHEMISTRY
The clinical blochemistry parameters were not changed by treatment.

Alanine aminotransferase (ALAT) activity, Aspartate aminotransferase (ASAT) activity, and inorganic phosphate values were statistically significant decreased and total protein values were statistically significant increased in the males of group 3 (200 mg/kg) when compared of the control values. Alanine aminotransferase (ALAT) activity, Aspartate aminotransferase (ASAT) activity, bilirubin, and triglyceride values were increased among high dose females, being mainly attributable to one high individual value (female no. 77). On exclusion of this value, average values were slightly decreased for ALAT and ASAT, and bilirubin and triglyceride were similar when compared to the controls.
Creatine values were statistically significant decreased in females of group 2 (50 mg/kg), and glucose values were statistically significant increased in females of group 3 (200 mg/kg) when cempared to the control values. However, similar findings in the opposite sex were absent and no dose relationship was observed. Therefore, the toxicological significance of these findings were considered to be irrelevant.
Chloride values of males of group 4 (1000 mg/kg) were statistical significant decreased, and total globuline values were statistical significant increased in males of groups 3 and 4. This was considered to be due to slightly high or low control values respectively.


NEUROBEHAVIOUR
No changes were observed in hearing ability, pupillary reflex, static righting reflex and grip strength in the treated animals, when compared to control animals.

Extremely increased motor activity was noted by the high sensors for the 200 mg/kg treated males (no. 23, 25 and 28). Since an increase in motor activity recorded by the high sensors is unlikely to occur without an concurrent change recorded by the low sensors, the increased motor activity was considered to have occurred by chance and of no toxicological significance.
Increased motor activity was noted by the low sensors for the 50 mg/kg (no. 14) and 1000 mg/kg treated males (no. 32 and 33). Since no corroborative findings were noted during clinical observations of the animals, this was considered to have occurred by chance without any toxicological relevance.
Decreased motor activity was noted by the low sensors for one control female (no. 41) and one 1000 mg/kg treated female (no. 71). Since the counts per sample period were often very low or even zero, these recordings were excluded from interpretation.


ORGAN WEIGHTS
Organ weights and organ:body weight ratios of treated animals were considered to be similar to those of control animals.

GROSS PATHOLOGY
Macroscopic observations of the remaining animals at necropsy did not reveal any alterations that were considered to have arisen as a result of treatment.
Six males of the 1000 mg/kg and 2 males of the 200 mg/kg dose group showed a greenish contents in the gastro-intestinal tract. In the absence of correlated microscopic findings these findings were considered to be due to the presence of undigested pigment, and although treatment-related, of limited toxicological significance.
At the 1000 mg/kg dose group, one male showed yellow foci on the lungs, and another male showed yellow foci on the lungs, a yellowish discolouration of the trachea and oesophagus. These findings were considered to be due to gavage errors, and without toxicological significance.
One male of the control group which died spontaneously showed a thoracic cavity containing cloudy gray/white fluid. One male of 200 mg/kg dose group was killed in extremis and showed a gastro-intestinal tract which contained fluid and was distended with gas, a dark red discolouration of the glandular mucosa of the stomach, and a spleen reduced in size.
Incidental findings included an enlarged caecum or adrenal glands, the testes, epididymis or seminal vesicles reduced in size, and red foci on the thymus.
Three females in the 200 mg/kg dose group and one female in the 50 mg/kg dose group showed a dark red discolouration of the mandibular lymph node. Incidental findings included a caecum with a greenish contents, pelvic dilatation of the kidney, a red-brown discolouration of the clitoral gland, irreguter surface of the spleen, and a thymus reduced in size.


HISTOPATHOLOGY: NON-NEOPLASTIC
There were no microscopic findings recorded which could be attributed to treatment with the test substance.

All microscopic findings were within the range of background pathology encountered in Wistar rats of this age and strain and occurred at similar incidences and severity in both control and treated rats.
The assessment of the integrity of the spermatogenetic cycle did not provide any evidence of impaired spermatogenesis.

OTHER:
There were no treatment related findings on reproduction. Details are presented in section 7.8.

Effect levels

Dose descriptor:

NOAEL

Effect level:

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

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

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/day. Oral dosing of male and fernale Wistar rats (10 per sex and group) 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.