(E)-3-(benzyl(4-((4-nitrophenyl)diazenyl)phenyl)amino)propanenitrile

Endpoint summary

Description of key information

With regard to the suacute oral toxicity study, the 'No Observed Effect Level" (NOEL) is 62.5 mg/kg body weight per day. However, no clear toxic effects were observed at the dose levels of 250 and 1000 mg/kg bw/day; hence the 'No Observed Adverse Effect Level" (NOAEL) is considered to be 1000 mg/kg bw/day.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

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

Groups of male and female rats received T-9601 by oral gavage at dose levels of 0, 6.25, 250 and 1000 mg/kg body weight per day for 28 days. On day 29 five males and five females from each group were killed and necropsied. Five males and five females from the control and high dose group were killed and necropsied after a recovery

period of 14 days. Behaviour and state of health were observed daily in all groups. Body weights and food consumption were recorded twice weekly, and water consumption once weekly. Once before the first treatment and thereafter once a week detailed clinical observations were performed in all animals outside the home cage in a standard arena ('open field'). Additionally, the animals were examined for opacity of the refracting media of the eyes, damage to the oral mucosa, and impairment of dental growth. Neurotoxicological measurements including assessment of sensory function, motor activity, forelimb and hindlimb grip strength were conducted at the end of the treatment period. Haematological examinations and clinical chemistry were carried at the end of the treatment period and after the recovery period. Urine analysis was carried out at the end of the treatment period and after the recovery period. During necropsy the animals were examined for macroscopically visible abnormalities the main organs weighed and the organ to body weight ratios calculated. Many organs and tissues were processed for histopathological examination and checked for microscopically visible changes. Body weights, haematological and clinical chemistry data, urine data (volume, specific weight), absolute and relative organ weights, neurotoxicological measurements (motor activity, forelimb and hindlimb grip strength) were analysed with the aid of a statistical program to show differences compared to the controls

No deaths occurred throughout the study. Behaviour and state of health remained unaffected by the administration of the test compound in all dose groups. Neurotoxicological parameters remained unaffected by the administration of the test compound in all groups. Body weight development, food and water consumption remained unaffected by the administration of the test compound in all groups.

Haematological examination of the final values revealed slightly decreased red blood cell counts in females from the intermediate and high dose group. Haemoglobin and haematocrit levels were slightly decreased in females from the high dose group. Males from the high dose group showed slightly increased white cell counts. No compound related changes were observed after the recovery period. Clinical chemistry examinations did not reveal any compound-related effect. Urine was discoloured dark yellow in both sexes from the high dose group. Remaining urine parameters and urine sediments did not reveal any compound-related change.

Liver weights were slightly increased in males from the intermediate and high dose group. These changes were no longer observed at the end of the recovery period. Yellow discoloration of adipose tissue was observed at necropsy in all dose groups This finding was reversible by the end of the recovery period in males, but still present in females. Histopathological examinations did not reveal any compound-related effect.

In conclusion, slight decreases in erythrocyte counts, haemoglobin and haematocrit values were observed in females after repeated oral administration of T-9601 at the daily dose of 1000 mg/kg body weight. Males showed slightly increased liver weights. Slight decreases in erythrocyte counts (females) and slightly increased liver weights (males) were also observed at the daily dose of 250 mg/kg body weight. A compound-related effect cannot be excluded, however, the changes were minor and there were no histopathological correlates for anaemia or liver damage. Likewise, clinical chemistry parameters were inconspicuous, and histopathological examination did not reveal any compound-related effect. No compound-related effects were observed at the dose level of 62.5 mg/kg body weight per day.

With regard to the present study the 'No Observed Effect Level" (NOEL) is 62.5 mg/kg body weight per day. However, no clear toxic effects were observed at the dose levels of 250 and 1000 mg/kg per day; hence the 'No Observed Adverse Effect Level" (NOAEL) is considered to be 1000 mg/kg bw/day.

Justification for classification or non-classification

The above studies have all been ranked reliability 1 according to the Klimisch et al system. This ranking was deemed appropriate because the studies were conducted to GLP an in compliance with agreed protocols. Sufficient dose ranges and numbers are detailed; hence it is appropriate for use based on reliability and animal welfare grounds. As the effects are considered adaptive rather than toxicological, no classification is proposed.

 

The above results triggered no classification under the Dangerous Substance Directive (67/548/EEC) and the CLP Regulation (EC No 1272/2008). No classification for prolonged effects is therefore required.