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

Carcinogenicity

Description of key information

Carcinogenicity of Pigment Yellow 12, the structural analogues, have intensively been investigated. Reliable (RL2) carcinogenicity studies in rats and mice are available for Pigment Yellow 12 and strucrual analogue pigment yellow 83, which all gave negative results. Pigment Yellow 12 has been investigated in two independent laboratories which both studied the effects after chronic exposure of rats and mice. The studies performed at the “Laboratorium für Pharmakologie und Toxikologie” used NMRI mice and Sprague Dawley rats which received up to 9000 ppm Pigment Yellow 12 in diet. Fischer 344 rats and B6C3F1 mice received up to 50000 ppm Pigment Yellow 12 in diet in the studies performed at the National Cancer Institute.

The „Laboratorium für Pharmakologie und Toxikologie“ also performed carcinogenicity tests with structural analogue Pigment Yellow 83 using NMRI mice and Sprague Dawley rats. The animals received up to 9000 ppm pure test item. In two parallel experiments the animals received up to 9000 ppm Pigment Yellow 83 which was intentionally contaminated with 20 ppm 3,3‘-dichlorobenzidine. No carcinogenic effects were observed in any of these tests.

 

Investigations on genotoxicity of Diarylide Yellow Pigments in vitro and in vivo gave negative results (see section 5.7). Toxicokinetic studies with Diarylide Yellow Pigments indicated that these substances can be considered likely not to be bioavailable. Therefore, it is concluded that Pigment Yellow 12 is not carcinogenic and have not to be classified as carcinogenic.

Please refer also to the read across justification, IUCLID Chapter 13.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

carcinogenicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Species:

mouse

Route of administration:

oral: feed

Duration of treatment / exposure:

104 weeks

Remarks:

Doses / Concentrations:
1000, 3000, 9000 ppm
Basis:
nominal in diet

Statistics:

- variance analysis according to Peto
- Student's t-test

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 examined

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

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

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:

no effects observed

Relevance of carcinogenic effects / potential:

The study design is in accordance with existing guidelines. Therefore, the results are considered relevant for the evaluation of the carcinogenic potential of the test item.

Key result

Dose descriptor:

NOAEL

Effect level:

9 000 ppm (nominal)

Sex:

male/female

Basis for effect level:

other: no increased tumour incidence in treated animals in comparison to controls, 9000 ppm in diet correspond to 1957.1 mg/kg bw/da and 2030.6 mg/kg bw/day in male and female mice, respectively (calculated in the study report on basis of food consumption)

Key result

Critical effects observed:

no

Conclusions:

The toxicity potential of registration substance is assessed using analogue approach.
Chronic feeding of NMRI mice with up to 9000 ppm test item in diet (corresponding to 1957 and 2030 mg/kg bw/day in male and female mice, respectively) did not result in an increased tumour incidence in comparison to the control animals, indicating that the test item is not carcinogenic.

Executive summary:

The toxicity potential of registration substance is assessed using analogue approach.

NMRI mice (50 per sex per dose) were exposed to 1000, 3000, 9000 ppm test item in feed (corresponding to 214, 649, 1957 mg/kg bw/da and 219, 681, 2030 mg/kg bw/day in male and female mice, respectively) for 104 weeks. The test item did not induce a treatment related increase in toxicity or tumour incidences. The results of this study do not provide evidence for carcinogenicity of the test item in NMRI mice.

Reference 2

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From JAN 1974 to APR 1976

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 451 (Carcinogenicity Studies)

Deviations:

not specified

GLP compliance:

no

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: S. IVANOVAS GmbH & Co, Med. Versuchstierzucht KG (Kissleg, Germany)
- Age at study initiation: 26 (males) -27 (females) days
- Weight at study initiation: 18.1 - 20.1 g
- Housing: individually in Macrolon cages (Type I)
- Diet: Altromin 1321 (Altromin, Lage), ad libitum
- Water: tap water, ad libitum
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 +/- 0.5
- Humidity (%): 60 +/- 3
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

104 weeks

Frequency of treatment:

daily

Post exposure period:

none

Remarks:

Doses / Concentrations:
1000, 3000, 9000 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

50

Control animals:

yes, plain diet

Positive control:

none

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice per day


DETAILED CLINICAL OBSERVATIONS: No


BODY WEIGHT: Yes
- Time schedule for examinations: weekly


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- 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
- Time schedule for examinations: daily


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: once, immediately before sacrifice
- Dose groups that were examined: all animals


HAEMATOLOGY: No


CLINICAL CHEMISTRY: No


URINALYSIS: No


NEUROBEHAVIOURAL EXAMINATION: No


OTHER:
at the end of the exposure period the following investigations were performed:
- audiometry (simple sound test)
- inspection of denture
- organ weights from 7-8 organs (heart, liver, lungs, spleen, kidney, thymus, brain, testis)

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes (animals of the control and highest dose group; paraffin sections, Haematoxylin-Eosin staining):
heart, lung, liver (additionally: frozen sections with Sudan stainings), kidney, spleen, adrenal, thymus, pituitary, brain, gonads, thyroid, prostate, uterus, seminal vesicle, mammary gland, stomach, duodenum, colon, salivary gland, lymph nodes, eye and optic nerve, urinary bladder, bone marrow, neoplastic lesions, bones
- histopathological investigations of animals of the lower dose groups were performed, if they died or were sacrificed in the meantime and revealed macroscopic findings

Statistics:

- variance analysis according to Peto
- Student's t-test

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 examined

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

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

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:

no effects observed

Relevance of carcinogenic effects / potential:

The study design is in accordance with existing guidelines. Therefore, the results are considered relevant for the evaluation of the carcinogenic potential of the test item.

Key result

Dose descriptor:

NOAEL

Effect level:

9 000 ppm (nominal)

Sex:

male/female

Basis for effect level:

other: no increased tumour incidence in treated animals in comparison to controls, 9000 ppm in diet correspond to 1957.1 mg/kg bw/da and 2030.6 mg/kg bw/day in male and female mice, respectively (calculated in the study report on basis of food consumption)

Key result

Critical effects observed:

no

 

- no effects on behaviour, appearance, faeces, feed and drinking water uptake, eyes, hearing, dentition, mortality, body weight development

- no substance induced macroscopic or histological changes

- no substance related effects on the tumour incidence (overall tumour rate: 42%, 45%, 40%, 46% in the control, 1000 ppm, 3000 ppm and 9000 ppm dose group, respectively; males: 30%, 36%, 24%, 40%, females: 54%, 54%, 56%, 52% in the control, 1000 ppm, 3000 ppm and 9000 ppm dose group, respectively) - 1000, 3000, 9000 ppm test item in diet correspond to 214, 649, 1957 mg/kg bw/day in male and 219, 681, 2031 mg/kg bw/day in female mice, respectively

Conclusions:

Chronic feeding of NMRI mice with up to 9000 ppm test item in diet (corresponding to 1957 and 2030 mg/kg bw/day in male and female mice, respectively) did not result in an increased tumour incidence in comparison to the control animals, indicating that the test item is not carcinogenic.

Executive summary:

NMRI mice (50 per sex per dose) were exposed to 1000, 3000, 9000 ppm test item in feed (corresponding to 214, 649, 1957 mg/kg bw/da and 219, 681, 2030 mg/kg bw/day in male and female mice, respectively) for 104 weeks. The test item did not induce a treatment related increase in toxicity or tumour incidences. The results of this study do not provide evidence for carcinogenicity of the test item in NMRI mice.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 957 mg/kg bw/day

Study duration:

chronic

Species:

mouse

Quality of whole database:

reliable

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Mode of Action Analysis / Human Relevance Framework

There is no evidence for species specific effects of the substance. Therefore, the results of the in vitro/in vivo data are regarded as relevant for humans.

Justification for classification or non-classification

Due to the negative findings in several reliable studies on carcinogenicity of Pigment Yellow 12 and its strucutral analogue, Pigment Yellow 83, in rats and mice and in the absence of any mutagenic activity of the substances of this category Diarylide Yellow Pigments of this category have not to be classified as carcinogenic according to Regulation (EC) No 1272/2008.