Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate

Carcinogenicity

Description of key information

The No Observed Adverse Effect Level (NOAEL) for Chocolate Brown HT (Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate) in male/ female Wistar rats was found to be 500 mg/Kg/day

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from a peer reviewed publication

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

The effect of Chocolate Brown HT on Wistar derived rats was studied with respect to mortality, body-weight gain, food or water consumption, haematology, renal function, serum constituents, organ weight or histopathology and carcinogenicity over a period of 2 yrs.

GLP compliance:

not specified

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data available
- Age at study initiation: No data available
- Weight at study initiation:
Males: 54-80 g
Females: 53-82 g
- Fasting period before study: No data available
- Housing: 4/cage
- Diet (e.g. ad libitum): ground Spratts Laboratory Diet No.1 ad libitum
- Water (e.g. ad libitum): Water ad libitum
- Acclimation period: No data available

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20± 1 OC
- Humidity (%): 50-60%
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): No data available


IN-LIFE DATES: From: To: No data available

Route of administration:

oral: feed

Vehicle:

other: Spratts Laboratory Diet No. 1

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): No data available
- Mixing appropriate amounts with (Type of food): ground Spratts Laboratory Diet No.1 ad libitum
- Storage temperature of food: No data available

VEHICLE
- Justification for use and choice of vehicle (if other than water): No data available
- Concentration in vehicle: 0, 25, 100 and 500 mg/Kg/day in the diet
- Amount of vehicle (if gavage): No data available
- Lot/batch no. (if required): No data available
- Purity: No data available

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

2 years

Frequency of treatment:

daily

Post exposure period:

no details available

Remarks:

Doses / Concentrations:
0, 25, 100 and 500 mg/Kg/day
Basis:
nominal in diet

No. of animals per sex per dose:

48 /sex/dose

Control animals:

yes, concurrent vehicle

Details on study design:

No data available

Positive control:

No data available

Observations and examinations performed and frequency:

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

DETAILED CLINICAL OBSERVATIONS: No data
- Time schedule:

BODY WEIGHT: Yes
- Time schedule for examinations: First day of feeding and at week 1,4, 7 and 11 of treatment

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: measured over the 48-h period commencing at the same time as the food intake

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

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At week 14, 27, 55 and 80
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: 10 male and 10 female rats
- Parameters checked in table [No.?] were examined: Haemoglobin content, packed cell volume and counts of erythrocytes and total leucocytes. Reticulocyte and differential white cell counts were carried out in blood samples from control rats and those given 500mg/Kg/bw Chocolate Brown HT in the diet for 14 and 27 weeks only

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: After week 104
- Animals fasted: No data
- How many animals:
- Parameters checked in table [No.?] were examined: Serum was analysed for its content of urea, glucose, total protein and albumin and for the activities of glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase and lactic dehydrogenase

URINALYSIS: Yes
- Time schedule for collection of urine: At weeks 14, 27, 56 and 102
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters checked in table [No.?] were examined.

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

OTHER:

Sacrifice and pathology:

GROSS PATHOLOGY: Yes; the brain,
heart, liver, spleen, kidneys, stomach, small intestine, caecum, adrenals,
gonads, pituitary and thyroid were weighed.

HISTOPATHOLOGY: Yes; Samples of the brain, heart, liver, spleen, kidneys, stomach, small intestine, caecum, adrenals, gonads, pituitary and thyroid together with samples of all major tissues and organs and of any other tissue appearing abnormal at autopsy were preserved in 10% buffered formalin until prepared for histological examination.

Statistics:

Statistical calculations are based on a level of significance of at least P = 0.05.

Clinical signs:

no effects observed

Description (incidence and severity):

Cumulative mortality observed was similar in the treated and control animals throughout the 2-year period

Mortality:

no mortality observed

Description (incidence):

Cumulative mortality observed was similar in the treated and control animals throughout the 2-year period

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No statistically significant differences between treated and control animals observed.

Food efficiency:

not examined

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

no effects observed

Description (incidence and severity):

No statistically significant differences between treated and control animals observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

There were no statistically significant differences between treated and control animals in the terminal haematological studies. Any hematological changes detected were not considered to be treatment related

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No significant differences between treated and control animals observed

Urinalysis findings:

no effects observed

Description (incidence and severity):

No significant differences between treated and control animals observed

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

The only statistically significant differences between treated and control rats were slightly higher relative spleen and kidney weights in males given dose at 500 mg/Kg day and a slightly higher relative spleen weight in females given 25mg/Kg day

Gross pathological findings:

no effects observed

Description (incidence and severity):

High incidence of adenosis and fibroadenosis in the female rats, but the incidences in the treated and control animals showed no statistical differences.

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: Cumulative mortality was similar in the treated and control animals throughout the 2-year period except for one statistically significant value at week 72 (7 deaths compared with none in the controls) in males given 500mg/Kg/day

BODY WEIGHT AND WEIGHT GAIN: No data available

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No statistically significant differences between treated and control animals observed.

The approximate total intakes of the colouring consumed per rat up to week 66 for the high treatment levels was 109.8 g for males and 83.9 g for female rats. The corresponding values up to week 102 were 160.8 g/rat by the males and 128.2 g/rat for the females.

FOOD EFFICIENCY: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No statistically significant differences between treated and control animals observed

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: There were several isolated statistically significant differences between treated and control rats in the results of the interim haematological examinations. These consisted of a reduced haemoglobin concentration in males given 500 mg/Kg/day for 27 weeks and a reduced red cell count in females fed diets containing 500 mg/Kg/day for 27 weeks. In addition, the white cell counts were higher than the control value in females given 500 mg/Kg/day of the colouring for 14 weeks. There were no statistically significant differences between treated and control animals in the terminal haematological studies.

Any hematological changes detected were not considered to be treatment related.

CLINICAL CHEMISTRY: No significant differences between treated and control animals observed

URINALYSIS: No significant differences between treated and control animals observed

NEUROBEHAVIOUR: No data

ORGAN WEIGHTS:
The only statistically significant differences between treated and control rats in relative organ weights were slightly higher relative spleen and kidney weights in males given diet containing 500 mg/Kg day Chocolate Brown HT

GROSS PATHOLOGY: No indication of pigmentation or storage phenomena was observed in any tissues.

HISTOPATHOLOGY: NON-NEOPLASTIC: High incidence of adenosis and fibroadenosis in the female rats, but the incidences in the treated and control animals showed no statistical differences.

The incidence of tumours was low in all groups, the most common tumours being mammary adenomas and fibroadenomas in the female rats, interstitial cell tumours of the testis, and subcutaneous fibromas in both sexes. The incidence of these findings in the treated and control animals did not differ statistically. Very few of the tumours were malignant.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)

HISTORICAL CONTROL DATA (if applicable): No data

Key result

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Tumorogenic but not treatment related Clinical signs, body weight changes, hematological studies, urinalysis, clinical chemistry, gross and histopathology and carcinogenicity

Conclusions:

The No Observed Adverse Effect Level (NOAEL) for Chocolate Brown HT (Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate) in male/ female Wistar rats was found to be 500 mg/Kg/day

Executive summary:

The effect of Chocolate Brown HT ( Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate) on male and female Wistar rats was studied. The test material was given in the diet for 2 years. These treatments had no adverse effect on mortality, body-weight gain, food or water consumption, haematology, renal function, serum constituents, organ weight or histopathology. The scattered changes detected in the haematological studies at weeks 14, 27 and 55 were not related to treatment and none of these differences were evident at weeks 80 or 104. No effects attributable to treatment were detected by urine examination, renal concentration tests or serum analysis. In rats showing some reduction in testis weight, no lesions differing in type or incidence from those in control rats were found on histological examination. The incidence of testicular tumours was lower in this group than in the control rats. Thus this decreased testicular weight cannot have been related to treatment. The incidence of tumours in this study was low and was clearly unrelated to treatment, being similar in both test and control groups.

The No Observed Adverse Effect Level (NOAEL)for Chocolate Brown HT in male/ female Wistar rats was found to be 500 mg/Kg/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

500 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Data is of K2 level from a peer reviewed publication

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available information from reliable sources, the substance is likely to be non-carcinogenic.

Additional information

Based on the available data for carcinogenicity of the target substance disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate the following results are summarized:

In key study, the effect of Chocolate Brown HT ( Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate) on male and female Wistar rats was studied. The test material was given in the diet for 2 years. These treatments had no adverse effect on mortality, body-weight gain, food or water consumption, haematology, renal function, serum constituents, organ weight or histopathology. The scattered changes detected in the haematological studies at weeks 14, 27 and 55 were not related to treatment and none of these differences were evident at weeks 80 or 104. No effects attributable to treatment were detected by urine examination, renal concentration tests or serum analysis. In rats showing some reduction in testis weight, no lesions differing in type or incidence from those in control rats were found on histological examination. The incidence of testicular tumours was lower in this group than in the control rats. Thus this decreased testicular weight cannot have been related to treatment. The incidence of tumours in this study was low and was clearly unrelated to treatment, being similar in both test and control groups. The No Observed Adverse Effect Level (NOAEL) for Chocolate Brown HT in male/ female Wistar rats was found to be 500 mg/Kg/day.

While in supporting study, Groups of 48 male and 48 female mice were given diets containing 0, 14.3, 143 and approx. 715 mg/kg/day Chocolate Brown HT (Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate)for 80 weeks. There was a slightly reduced body weight gain and a lower heart weight in males given the highest dietary level. At the same level at week 77 the packed cell volume and total leucocyte count values in females were lower than those of the controls. However, the relationship of these findings to the treatment was questionable, as was the increased incidence of leucocytic infiltration of the liver in the female mice at the approx. 715 mg/Kg/day of treatment. A brown coloration of internal organs seen at the highest treatment level was due probably to the Chocolate Brown HT. The distribution of tumours was similar in all groups, lymphosarcomata were more frequently found in the treated animals, though there was no indication of any dose frequency relationship and it was concluded that there was no evidence of a carcinogenic effect with doses up to approx. 715 mg/kg/day was observed. The carcinogenicity No Observed Effect Level (NOEL) for the given test material is found to be approx. 715 mg/kg/day.

Based on the studies summarized above it can be observed that the substance did not showed any evidence of carcinogenic effects. Thus based on the above values it can be concluded that target substance (CAS NO 4553-89-3) is considered to be non carcinogenic in nature.