1-phenylazo-2-naphthol

Endpoint summary

Description of key information

Repeated dose toxicity: oral

Repeated dose oral toxicity study was performed on mice to determine the toxic nature of 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14). In a 14 day repeated dose toxicity study,  B6C3F₁male and female mice were treated with C. I. Solvent Yellow 14 in the concentration of 0,6,000, 12,500, 25,000, 50,000, or 100,000 ppm ( 0, 1200, 2500, 5000, 10000 and 20000 mg/kg/day) orally in diet. All male and female mice were died at 12500, 25000, 50000 and 100000 ppm (2500, 5000, 1000 and 20000 mg/kg/day) dose. The mice were observed for clinical signs and mortality, gross and histopathology. No clinical signs of toxicity were noted and severe gross pathological effects such as dark red intestines and mildly congested livers were observed at 2500 mg/Kg/day and at higher doses. Therefore, No Observed Adverse Effect Level (NOAEL) was 1200 mg/kg/day when B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: 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 study report

Qualifier:

no guideline available

Principles of method if other than guideline:

14 day repeated dose toxicity study of C. I. Solvent Yellow 14 orally in B6C3F1 mice.

GLP compliance:

no

Limit test:

no

Specific details on test material used for the study:

- Name of test material: C. I. Solvent Yellow 14 (1-phenylazo-2-naphthol)
- Molecular formula: C16H12N2O
- Molecular weight: 248.284 g/mol
- Substance type: Organic
- Physical state: solid
- Impurities (identity and concentrations): 5.9 %
- Purity: 94.1% pure

Species:

mouse

Strain:

B6C3F1

Details on species / strain selection:

No data

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: NCI Frederick Cancer Research Center (Frederick, MD)
- Age at study initiation: 6 week old
- Weight at study initiation: No data available
- Fasting period before study: No data available
- Housing: Mice were housed by species, five per cage, in solid-bottom polycarbonate cage supplied with hardwood chip bedding. Cages and bedding were changed twice per week. Rack Filters with Dupon 2024 Spun-Bonded polyester filters were used.
- Diet (e.g. ad libitum): Purina Laboratory Chow, ad libitum in feed hoppers that were changed weekly.
- Water (e.g. ad libitum): Tap water supplied and analyzed by the Columbus, Ohio, water department, ad libitum via an automatic watering system.
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21° to 23°C
- Humidity (%): 40%-60% (relative humidity)
- Air changes (per hr): 15 times per hour
- Photoperiod (hrs dark / hrs light): Standard white fluorescent lighting provided illumination 12 hours per day.

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

Route of administration:

oral: feed

Details on route of administration:

No data

Vehicle:

other: Feed (Purina Laboratory Chow animal meal)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: Diets were formulated by mixing weighed amounts of Purina Laboratory Chow animal meal and the test chemical for 15 minutes in a Patterson-Kelly twin-shell blender equipped with an intensifier bar to give a dose range of 0, 1200, 2500, 5000, 10000 and 20000 mg/kg/day.

DIET PREPARATION
- Rate of preparation of diet (frequency): In every 10 days
- Mixing appropriate amounts with (Type of food): Purina Laboratory Chow
- Storage temperature of food: Formulated diets were stored at 23°C for no longer than 10 days

VEHICLE
- Justification for use and choice of vehicle (if other than water): Purina Laboratory Chow
- Concentration in vehicle: 6,000, 12,500, 25,000, 50,000 and 100,000 ppm (0, 1200, 2500, 5000, 10000 and 20000 mg/kg/day)
- Amount of vehicle (if gavage): No data available
- Lot/batch no. (if required): Not required
- Purity: No data available

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical verification of doses were performed by using Gilford 2400-S spectrophotometer

Duration of treatment / exposure:

14 days

Frequency of treatment:

Daily

Remarks:

0, 6,000, 12,500, 25,000, 50,000 and 100,000 ppm (0, 1200, 2500, 5000, 10000 and 20000 mg/kg/day)
nominal in diet

No. of animals per sex per dose:

Total: 60
0 mg/Kg/day : 5 male, 5 female
1200 mg/Kg/day : 5 male, 5 female
2500 mg/Kg/day : 5 male, 5 female
5000 mg/Kg/day : 5 male, 5 female
10000 mg/Kg/day : 5 male, 5 female
20000 mg/Kg/day : 5 male, 5 female

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: No data available
- Rationale for animal assignment (if not random): Animals assigned to cages according to a table of random numbers.
- Rationale for selecting satellite groups: No data available
- Post-exposure recovery period in satellite groups: No data available
- Section schedule rationale (if not random): No data available

Positive control:

No data

Observations and examinations performed and frequency:

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

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

BODY WEIGHT: No data available
- Time schedule for examinations: No data available

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No data available
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data available
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data available

FOOD EFFICIENCY: No data available
- 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 available

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

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

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

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

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

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

OTHER: No data available

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Gross pathological abnormalities were examined.

HISTOPATHOLOGY: No data available

Other examinations:

No data available

Statistics:

No data available

Clinical signs:

no effects observed

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

not specified

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:

not specified

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:

effects observed, treatment-related

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

Clinical signs and mortality :
Mortality:
When treated with 12500, 25000, 50000 and 100000 ppm, all male and female mice were died.

Clinical signs:
No sign of toxicity were observed in treated mice.

Body weight and weight gain: No data available

Food consumption and compound intake: No data available

Food efficiency: No data available

Water consumption and compound intake: No data available

Opthalmoscopic examination: No data available

Haematology: No data available

Clinical chemistry: No data available

Urinanalysis: No data available

Neurobehaviour: No data available

Organ weights: No data available

Gross pathology: When treated with 2500, 5000, 10000 and 20000 mg/kg/day, severe effects were observed in male and female mice. Dark red intestines and mildly congested livers were observed in 1200 mg/Kg/day treated male and female mice. Dark red intestines and mildly congested livers were observed in 6000 ppm treated male and female mice.

Histopathology: No data available

Dose descriptor:

NOAEL

Effect level:

1 200 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

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

Critical effects observed:

no

Table: Survival of mice in 14 days study period

Dose (mg/Kg/day)	Survival
	Male	Female
1200	5/5	5/5
2500	0/5	0/5
5000	0/5	0/5
10000	0/5	0/5
20000	0/5	0/5

Conclusions:

The No Observed Adverse Effect Level (NOAEL) was 1200 mg/kg/day when B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14).

Executive summary:

Repeated dose oral toxicity study was performed on mice to determine the toxic nature of C. I. Solvent Yellow 14. In a 14 day repeated dose toxicity study ,  B6C3F₁ male and female mice were treated with C. I. Solvent Yellow 14 in the concentration of 0,6,000, 12,500, 25,000, 50,000, or 100,000 ppm orally in diet. All male and female mice were died at 12500, 25000, 50000 and 100000 ppm (2500, 5000, 1000 and 20000 mg/kg/day) dose. The mice were observed for clinical signs and mortality, gross and histopathology. No clinical signs of toxicity were noted and severe gross pathological effects such as dark red intestines and mildly congested livers were observed at 2500 mg/Kg/day and at higher doses. Therefore, No Observed Adverse Effect Level (NOAEL) was 1200 mg/kg/day when B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 200 mg/kg bw/day

Study duration:

subacute

Species:

mouse

Quality of whole database:

The data is Klimicsh 2 and from study report.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated dose toxicity: Oral

Data from study report was reviewed to determine the toxic nature of 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) upon repeated exposure by oral route. The studies are summarized as below:

In a 14 day repeated dose toxicity study (NTP, 1982),  B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) (CAS no 842-07-9) in the concentration of 0,6,000, 12,500, 25,000, 50,000, or 100,000 ppm orally in diet. All male and female mice were died at 12500, 25000, 50000 and 100000 ppm ( 0, 1200, 2500, 5000, 1000 and 20000 mg/kg/day) dose. The mice were observed for clinical signs and mortality, gross and histopathology. No clinical signs of toxcity were noted and severe gross pathological effects such as dark red intestines and mildly congested livers were observed at 2500 mg/Kg/day and at higher doses. Therefore, No Observed Adverse Effect Level (NOAEL) was 1200 mg/kg/day when B6C3F1 male and female mice were treated with C. I. Solvent Yellow 14. Accordingly a 91 day repeated dose toxicity study (NTP, 1982) was also performed. B6C3F1 male and female mice were treated with C. I. Solvent Yellow 14 (CAS no 842-07-9) in the concentration of 0, 500, 1,000, 2,000, 4,000 and 8,000 ppm (0, 83.4, 166.7, 333.4, 666.7 and 1333.3 mg/kg/day) orally in diet. All male and 5 female mice died on treatment with 1333.3 mg/Kg/day. The animals were observed for clinical signs, mortality, food consumption and gross and histopathalogy. Mean body weight gain was decreased on treatment of 333.4 and 666.7 mg/Kg/day. In addition, Splenic, renal and hepatic hemosiderosis and splenic congestion, necrosis, regeneration of renal cortical tubular epithelium and lymphoid depletion of the thymus were observed on treatment of 333.4 and 666.7 mg/Kg/day. Therefore, the No Observed Adverse Effect Level (NOAEL) is 166.7 mg/kg/day when B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14).

In a chronic repeated dose toxicity study (NTP, 1982), B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) (CAS no 842-07-9) in a concentration of 0, 500 or 1,000 ppm (0, 71.5 or 142.8 mg/Kg/day) orally in diet. No effects were observed on survival, clinical signs and food consumption of all treated mice as compared to control. Slightly decreased mean body weight were observed in 71.5and 142.8 mg/Kg/day after week 30 in males and after week 50 in females as compared to contorl. In addition, non-neoplastic lesion such as Alveolar/Bronchiolar adenoma of lung and malignant lymphoma of hematopoietic system, hepatocellular adenoma and hepatocellular carcinoma of Liver and follicular-cell adenoma of thyroid and neoplastic lesion such as Leukemia and malignant lymphomas of various types and in various locations were observed in treated mice. But, Each type of tumor represented has been encountered previously as a spontaneous lesion in aging B6C3F1mice and considered as non- carcinogenic for mice. Therefore, No observed adverse effect level (NOAEL) was 500 ppm (71.5 mg/kg/day) when B6C3F1 male and female mice were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) orally in diet for 105 weeks.

Similar studies were also performed on rats.

In a 14 day repeated dose subacute toxicity study (NTP, 1982), F344/N male and female rats were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) (CAS no 842-07-9) in the concentration of 0,6,000, 12,500, 25,000, 50,000 and 100,000 ppm (0, 600, 1250, 2500, 5000 or 10000 mg/Kg/day) orally in diet.1 male and 1 female died at 600 mg/Kg/day dose. All male and female rat died at 1250, 2500, 5000 and 10000 mg/Kg/day dose. In addition, severe gross pathological effects such as dark red intestines and mildly congested livers were observed at 600 mg/Kg/day and at higher doses. Therefore, the low observed adverse effect level (LOAEL) is 600 mg/Kg/day (6000 ppm) when F344/N male and female rats were treated with C. I. Solvent Yellow 14 orally in diet for 14 days. 

Another 91 day repeated dose toxicity study (NTP, 1982) was also performed. F344/N male and female rat were treated with C. I. Solvent Yellow 14 (CAS no 842-07-9) in the concentration of 0, 250, 500, 1,000, 2,000 and 4,000 ppm (0, 25, 50, 100, 200 and 400 mg/kg/day) orally in diet. No effects were observed on survival of treated rats as compared to control. Decrease in mean body weight was observed in 1000, 2000 and 4000 ppm (100, 200 and 400 mg/Kg/day) treated rat. Similarly, food consumption was decreased in 2000 and 4000 ppm (200 and 400 mg/Kg/day) treated rat as compared to control. In addition, Hepatic degeneration characterized by increased basophilia and a granular appearance of hepatocytes adjacent to the portal areas, while centrilobular hepatocytes had a hazy, almost vacuolated appearance were observed in 4000 ppm (400 mg/Kg/day) treated dose group and Pigment deposition in the tubular epithelium of the kidney cortex of 1000 ppm (100 mg/Kg/day) dose treated male and 500 ppm (50 mg/Kg/day) treated female rats were observed as compared to control. Therefore, No Observed Adverse Effect Level (NOAEL) is 1000 ppm (100 mg/kg/day) when F344/N male and female rat were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14).

In a chronic repeated dose oral toxicity study (NTP, 1982), F344/N male and female rats were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) (CAS no 842-07-9) in the concentration of 0, 250 or 500 ppm (0, 12.5 or 25 mg/kg/day) orally in diet. No effects were observed on survival, clinical sign and food consumption of all treated rat as compared to control. Decreased mean body weight was observed in 250 and 500 ppm (12.5 and 25 mg/Kg/day) treated rat as compared to control. In addition, Non-neoplastic lesions such as multifocal fibrosis of the cardiac valve, lymphoid hyperplasia of the lung in male rats and bile duct focal hyperplasia in female rats, atrophy of the pancreatic acinus, nephropathy and composed of eosinophilic or basophilic hepatocytes and accompanied by anangiectactic or cystic change small and multiple neoplastic nodules of the liver were observed in 250 and 500 ppm (12.5 and 25 mg/Kg/day) treated rats. Therefore, low observed adverse effect level (LOAEL) is 250 ppm (12.5 mg/kg/day) when F344/N male and female rats were treated with 1-phenylazo-2-naphthol (C. I. Solvent Yellow 14) orally for 104 weeks. However, the study was not considered to be adequate because small numbers of animals were used and the dosage may not have been at the maximum tolerated level.

Based on the data summarized, the test chemical 1-phenylazo-2-naphthol is not likely to classify as toxicant upon repeated application by oral route of exposure. The NOAEL for mice ranges between 71.5 - 1200 mg/Kg bw and for rats, the No observed adverse effect level ranges between 12.5 - <600 mg/Kg bw. For this reason, the study with maximum value for No observed adverse effect level is considered as key study.

Repeated dose toxicity: inhalation

According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance 1-phenylazo-2-naphthol, which is reported as 0.0000000734 mmHg (9.785e-06 Pa). Also considering the particle size distribution of the substance the majority of the particles were found to be in the size of 150 micrometer which is much larger size range compared to the inhalable particulate matter. Thus, exposure to inhalable dust, mist and vapour of the chemical 1-phenylazo-2-naphthol is highly unlikely. Therefore this study is considered for waiver.

Repeated dose toxicity: dermal

The acute toxicity value for 1-phenylazo-2-naphthol (as provided in section 7.2.3) is >2000 mg/kg body weight. The substance was also found to be not irrtating to skin. Also, given the use of the chemical as dye compound; repeated exposure by the dermal route is unlikely. Thus, it is expected that 1-phenylazo-2-naphthol shall not exhibit 28 day repeated dose toxicity by the dermal route. In addition, there is no dermal absorption data as well as no data available that suggests that 1-phenylazo-2-naphthol shall exhibit repeated dose toxicity by the dermal route. Hence this end point was considered for waiver.

Justification for classification or non-classification

Based on the data summarized, the test chemical 1-phenylazo-2-naphthol (CAS No.- 842 -07 -9) is not likely to classify as toxicant upon repeated application by oral route of exposure.