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

Endpoint summary

Description of key information

Repeated dose toxicity: via oral route;

The No Observed Adverse Effect level (NOAEL) for test chemical  is considered to be  in a dose range of 1000-2500 mg/Kg/day in redent for chronic study.

Repeated inhalation study:

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-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6) which is reported as 4.57E-012 mmHg at 25 C. Also considering the particle size distribution of the substance the majority of the particles was found to be in the size range of 150 to 10 micron which is much larger size range compared to the inhalable particulate matter .Thus, exposure to inhalable dust, mist and vapour of the chemical 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol is highly unlikely. Therefore this study is considered for waiver.

Repeated dermal study;

The acute toxicity value for 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6) (as provided in section 7.2.3) is >2000 mg/kg body weight. Also, given the use of the chemical; repeated exposure by the dermal route is unlikely since the use of gloves is common practice in industries. Thus, it is expected that 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol shall not exhibit 28 day repeated dose toxicity by the dermal route. In addition, there is no data available that suggests that 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol shall exhibit repeated dose toxicity by the dermal route. Hence this end point was considered for waiver.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

2 500 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Weight of evidence prepared from various qualified publication.

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

The data available for the test chemical was reviewed to determine the toxic nature 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6) repeated exposure by oral route. The study is as mentioned below:

Repeated dose toxicity: via oral route;

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.

Supported by other sub chronic study. Combined repeated dose and reproduction / developmental screening was performed to evaluate the toxic nature of test chemical. Male and female Crl:CD (SD) were used in the study. The test compound was dissolved in water and used at dose levels of 0, 40, 200 or 1000 mg/Kg/day. The male rats were treated for 42 days and female rats were treated for 41-47 days. Recovery group of 0 and 1000 mg/Kg/day was also included in the study. The treated animals were noted for clinical signs, functional battery observations, body weight, food consumption, urinanalysis, hematology, blood chemistry, organ weight changes and histopathology. No adverse effcets were noted in the various parameters studied. Based on the observations made,No Observed Adverse Effect Level (NOAEL) for test chemical is considered to be 1000 mg/Kg/day.

Based on the data available from the test chemical 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6) does not exhibit repeated dose oral toxicity in the range of 1000-2500 mg/kg bw. Hence the test chemical is not likely to classify as a repeated dose oral toxicity as per the criteria mentioned in CLP regulation.

Repeated inhalation study:

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-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6) which is reported as 4.57E-012 mmHg at 25 C. Also considering the particle size distribution of the substance the majority of the particles was found to be in the size range of 150 to 10 micron which is much larger size range compared to the inhalable particulate matter .Thus, exposure to inhalable dust, mist and vapour of the chemical 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol is highly unlikely. Therefore this study is considered for waiver.

Repeated dermal study;

The acute toxicity value for 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6) (as provided in section 7.2.3) is >2000 mg/kg body weight. Also, given the use of the chemical; repeated exposure by the dermal route is unlikely since the use of gloves is common practice in industries. Thus, it is expected that 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol shall not exhibit 28 day repeated dose toxicity by the dermal route. In addition, there is no data available that suggests that 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol shall exhibit repeated dose toxicity by the dermal route. Hence this end point was considered for waiver.

Based on the data available for the test chemical 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6)  does not exhibit toxic nature upon repeated exposure by oral, inhalation and dermal route of exposure and hence is not likely to classify as per the criteria mentioned in CLP regulation.

Justification for classification or non-classification

Based on the data available for the test chemical 1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol ( 85-83-6)  does not exhibit toxic nature upon repeated exposure by oral, inhalation and dermal route of exposure and hence is not likely to classify as per the criteria mentioned in CLP regulation.