1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol

Repeated dose toxicity: oral

Administrative data

Endpoint:

repeated dose toxicity: oral, other

Remarks:

Combined repeated dose repro-devp. Screen

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

Data is from NTIS report

Data source

Reference

Reference Type:

other: NTIS

Title:

Bioassay of Diarylanilide Yellow for Possible Carcinogenicity

Author:

U. S. Department of Commerce

Year:

1977

Bibliographic source:

National Technical Information Services,

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Combined repeated dose – carcinogenicity assay was performed to determine the toxic nature of test chemical upon repeated exposure by oral route

GLP compliance:

not specified

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)

Details on test material:

CAS name: 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide)
CAS no: 6358-85-6
EC no: 228-787-8

Test animals

Species:

rat

Strain:

Fischer 344

Details on species / strain selection:

No data

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River
Breeding Laboratories, Wilmington, Massachusetts
- Age at study initiation: 7 weeks old
- Weight at study initiation:
- Fasting period before study:
- Housing: Rats were housed five per cage by sex. During quarantine and for the first 6 weeks of study, they were kept in galvanized-steel wire-mesh cages suspended above newspapers. Newspapers were replaced daily, and cages and racks washed weekly. From week 6 rats were kept in suspended polycarbonate cages equipped with disposable nonwoven filter sheets. Clean bedding and cages were provided twice weekly.
Hardwood chips (Ab-sorb-dri® Wilner Wood Products Co.) were used through the first 3 months of study, then corncob bedding (SAN-I-CEL®, Paxten Processing Co.) for the next 12 months. and then another type of corncob bedding (Bed-o'CobS®, The Anderson's Cob Division) for the remainder of the bioassay.
- Diet (e.g. ad libitum): Wayne Lab-Blox® ad libitum
- Water (e.g. ad libitum): Water ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23° to 34°C
- Humidity (%): 10-85%
- Air changes (per hr): Incoming air was filtered through Tri-Dek® 15/40 denier Dacron® filters providing six changes of room air per hour.
- Photoperiod (hrs dark / hrs light): 12-hour-daily cycle

IN-LIFE DATES: From: To:

Administration / exposure

Route of administration:

oral: feed

Details on route of administration:

No data

Vehicle:

other: Feed

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The test chemical was administered to treated animals as a component of feed. The test chemical was mixed with feed in a 6 Kg Patterson-Kelly standard model stainless steel twin-shell V blender. After 20 mins of blending, the mixtures were placed in double plastic bags and stored at 4˚C in dark.

DIET PREPARATION
- Rate of preparation of diet (frequency): Weekly
- Mixing appropriate amounts with (Type of food): Wayne Lab-Blox®
- Storage temperature of food: at 4˚ for no longer than 2 weeks

VEHICLE
- Justification for use and choice of vehicle (if other than water): Wayne Lab-Blox®
- Concentration in vehicle: 0, 1250 or 2500 mg/Kg/day
- Amount of vehicle (if gavage): No data
- Lot/batch no. (if required): No data
- Purity: No data

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data

Duration of treatment / exposure:

78 weeks

Frequency of treatment:

Daily

Doses / concentrations

Remarks:

0, 2.5 or 5.0% (0, 1250 or 2500 mg/Kg/day)

No. of animals per sex per dose:

Total: 150 males and 150 females

0 mg/Kg/day: 50 males and 50 females
1250 mg/Kg/day: 50 males and 50 females
2500 mg/Kg/day: 50 males and 50 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: In order to establish the maximum tolerated concentrations of diarylanilide yellow for dministration to treated animals in the chronic studies, subchronic toxicity tests was conducted. Diarylanilide yellow was incorporated into the basal laboratory diet and fed ad libitum to four of the five rat groups in a dose range of 0.1, 0.3, 1.0, and 3.0 percent. The remaining group of each species served as a control group, receiving only the basal laboratory diet. The dosed dietary preparations were administered for a period of 8 weeks. A dosage inducing no mortality or body weight gain retardation in either sex was to be selected as the initial high dose in the chronic bioassay. No decreases in food consumption or significant weight depression relative to controls were observed in any group. All animals survived until necropsy (week 8). Although the external surfaces of all animals at all concentrations were bright yellow, gross necropsy revealed no abnormalities or organ discoloration other than the mucosal surfaces of the intestinal tract, which appeared bright yellow due to direct contact with the test compound.

In the Guidelines for Carcinogen Bioassay in Small Rodents it is indicated that a chronic dietary concentration of 5 percent (50,000 ppm) should not be exceeded. This applies even if the compound causes no toxicity during subchronic testing. An exception can be made under special circumstances. E.g. if the chemical is a major component of the human diet. Because no toxic symptoms or gross abnormalities were observed clinically or at necropsy- in animals receiving the tested concentrations, 5.0 percent was selected as the concentration to be administered to the high dose groups during the chronic bioassay.

- Rationale for animal assignment (if not random): Animals were assigned to groups and distributed among cages so that average body weight per cage was approximately equal for a given sex
- Rationale for selecting satellite groups: No data
- Post-exposure recovery period in satellite groups: No data
- Section schedule rationale (if not random): No data

Positive control:

No data

Examinations

Observations and examinations performed and frequency:

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

DETAILED CLINICAL OBSERVATIONS: Yes / No / No data
- Time schedule:

BODY WEIGHT: Yes
- Time schedule for examinations: Animals were weighed immediately prior to initiation of the experiment. Body weights were recorded twice weekly for
the first 12 weeks of the study and at monthly intervals thereafter.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes, Food consumption was monitored for seven consecutive days once a month for the first nine months of the bioassay and for three consecutive days each month thereafter.
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

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

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: No data
- Dose groups that were examined: No data

HAEMATOLOGY: No data
- Time schedule for collection of blood: No data
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: No data
- Parameters checked in table [No.?] were examined. No data

CLINICAL CHEMISTRY: No data
- Time schedule for collection of blood: No data
- Animals fasted: No data
- How many animals: No data
- Parameters checked in table [No.?] were examined. No data

URINALYSIS: No data
- Time schedule for collection of urine: No data
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data - Parameters checked in table [No.?] were examined. No data

NEUROBEHAVIOURAL EXAMINATION: No data
- Time schedule for examinations: No data
- Dose groups that were examined: No data
- Battery of functions tested: sensory activity / grip strength / motor activity / other: No data

OTHER: No data

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, The animals were euthanized by carbon dioxide inhalation, and were immediately necropsied. The presence of tissue masses and lesions was determined by monthly.

HISTOPATHOLOGY: Yes, The histopathologic examination consisted of gross and microscopic examination of major tissues, organs, or gross lesions taken from sacrificed animals and, whenever possible, from animals found dead.

Slides were prepared from the following tissues: skin, subcutaneous tissue, lungs and bronchi, trachea, bone marrow, spleen, lymph / nodes, thymus, heart, salivary gland, liver and bile duct, pancreas, esophagus, stomach, small intestine,large intestine, kidney, urinary bladder, pituitary, adrenal, thyroid, parathyroid, pancreatic islets, testis, prostate, brain, uterus, mammary gland, and ovary.

Other examinations:

No data

Statistics:

Refer below section

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

All the treated rats, both male and female, appeared bright yellow in color. The only other clinical sign recorded for male or female rats vas a hard crusted lesion on the back of one male control animal.

Mortality:

no mortality observed

Description (incidence):

In the males survival was quite high, as 74 percent of the high dose, 84 percent of the low dose, and 64 percent of the control rats survived until the end of the study despite the sacrifice of five high dose and five control rats in week 78. In the females, 66 percent of the high dose, 80 percent of the low dose, and 72 percent of the control rats survived until the end of the study, despite the sacrifice of five high dose and five control rats in week 78.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

The body weight patterns for control and treated rat groups of both sexes were generally equivalent throughout the treatment period

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

no effects observed

Description (incidence and severity):

In addition, the conjunctivas were faintly yellow as were most organs and internal mucosal surfaces.

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

With a few exceptions, the same variety of neoplasms occurred sporadically and randomly in the chemically treated and control groups. No particular organ or system seemed to be the target of this chemical. Sporadic and unusual neoplasms that occurred in the treated but rot in control animals were as follows: a metastatic chordoma of unknown origin occurred in the lung of 1/49 of the low dose males. and 1/49 of the low dose females had an osteogenic sarcoma.

Histopathological findings: neoplastic:

no effects observed

Description (incidence and severity):

The incidence-and variety of nonneoplastic degenerative, proliferative, and inflammatory lesions were similar in the control and the chemically treated rats, except for treatment-related basophilic /cytoplasm changes in hepatocytes of treated males and females.

Other effects:

not specified

Details on results:

No data

Effect levels

Dose descriptor:

NOAEL

Effect level:

2 500 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No significant effects were noted at the mentioned dose level

Remarks on result:

other: No toxic effects were observed

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The No Observed Adverse Effect level (NOAEL) for test chemical was considered to be 2500 mg/Kg/day.

Executive summary:

Combined repeated dose – carcinogenicity assay was performed to determine the toxic nature of test chemical upon repeated exposure by oral route. The study was performed using male and female F344 rats. The test chemical was mixed with feed and used at dose level of 0, 1250 or 2500 mg/Kg/day (0, 2.5 or 5.0%) for 109 weeks including 28 weeks of observation period. The animals were observed for clinical signs, mortality, changes in body weight and food consumption, opthalmology. The animals were subjected to gross pathology and histopathology. All the treated rats, both male and female, appeared bright yellow in color. The only other clinical sign recorded for male or female rats was a hard crusted lesion on the back of one male control animal. No statistically significant positive association was noted in the dosage and mortality. The body weight patterns for control and treated rat groups of both sexes were generally equivalent throughout the treatment period. In addition, the conjunctivas were faintly yellow as were most organs and internal mucosal surfaces. With a few exceptions, the same variety of neoplasms occurred sporadically and randomly in the chemically treated and control groups. No particular organ or system seemed to be the target of this chemical. Sporadic and unusual neoplasms that occurred in the treated but rot in control animals were as follows: a metastatic chordoma of unknown origin occurred in the lung of 1/49 of the low dose males and 1/49 of the low dose females had an osteogenic sarcoma. The incidence-and variety of nonneoplastic degenerative, proliferative, and inflammatory lesions were similar in the control and the chemically treated rats, except for treatment-related basophilic/cytoplasm changes in hepatocytes of treated males and females. Based on the observations made, the No Observed Adverse Effect level (NOAEL) for test chemical is considered to be 2500 mg/Kg/day.