4-nitrotoluene-2-sulphonic acid

Endpoint summary

Description of key information

NOAEL (oral; sub-chronic; rat) = 250 mg/kg bw/ day

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Dose descriptor:

NOAEL

250 mg/kg bw/day

Study duration:

subchronic

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

Repeated Dose Toxicity: Oral

An oral repeated dose toxicity study according to the guideline OECD 408 is available.The objective of this study was to determine the potential toxicity of 4-nitrotoluene-2-sulphonic acid, when given orally by gavage for 90 days to Wistar Han rats. In addition, a No Observed Adverse Effect Level (NOAEL) was evaluated.
Ten male and ten female Wistar Han rats were exposed to 100, 250 and 700 mg/kg bw/day of the substance for 90 days. A concurrent vehicle control (water) run.
Chemical analyses of formulations were conducted in Weeks 1, 6 and 13 to assess accuracy and homogeneity.
The following parameters and end points were evaluated in this study: clinical signs, functional observation tests, body weights, food consumption, ophthalmology, estrous stage determination, clinical pathology parameters (hematology, coagulation, clinical chemistry, and urinalysis), gross necropsy findings, organ weights, and histopathologic examinations.
Formulation analyses confirmed that formulations of test item in water were prepared accurately and homogenously.

No mortality occurred during the study period that was considered to be related to treatment with the test item. One female at 700 mg/kg/day was found dead on Day 28, which was regarded to be gavage-related error.
In males at 100 and 250 mg/kg/day a slightly higher incidence of minimal focal lymphocytic infiltrates in the glandular stomach was recorded, which was regarded to be test item-related, but in absence of any degenerative lesions considered to be non-adverse.
At 700 mg/kg/day, test item-related increased reticulocytes count and decreased hemoglobin concentration in males, and increased platelet counts and red blood distribution width in males and females were noted. Furthermore, a decrease in albumin levels and an increased level of cholesterol and HDL cholesterol in males, and a decreased total protein concentration in males and females was noted. In absence of a histopathological correlation and at the magnitude of change, these findings were considered to be not adverse.
At histopathological examination, test item-related morphological alterations were recorded in the stomach (glandular stomach) and consisted of inflammatory changes at minimal to mild degree and in a few animals consisted of mucosal hemorrhage and erosions and macroscopic dark red foci. These alterations were considered to be related to the irritating properties of the test item and regarded local test item-related findings. The combination of erosions with increased incidence and severity of lymphocytic and mixed cell infiltrates were considered to be adverse.
In the prostate gland, atrophy was recorded for a single male for which a relation to the treatment could not be excluded, but it was in line with the lower prostate gland weights recorded in males and females at 700 mg/kg/day. Atrophy of the prostate gland is a degenerative finding and therefore regarded to be adverse. In addition, lymphocytic infiltrates in the prostate gland were recorded at a slightly higher incidence and severity in males at 700 mg/kg/day, which was regarded to be non-adverse.
In conclusion, administration of 4-nitrotoluene-2-sulphonic acid by once daily oral gavage was well tolerated in Wistar Han rats at levels of up to 700 mg/kg/day. Adverse morphological changes were observed in the glandular stomach and prostate gland at 700 mg/kg/day. In the glandular stomach a combination of focal/multifocal lymphocytic infiltrates, diffuse mixed infiltrates, erosions and/or hemorrhage, correlating to macroscopic dark red foci were recorded in males and females. In the prostate gland a single atrophy was recorded. The other morphological and also clinical pathology findings observed in males and females at 100, 250 and 700 mg/kg/day were considered to be non-adverse.
Based on these results in this study, the No Observed Adverse Effect Level (NOAEL) for 4-nitrotoluene-2-sulphonic acid was considered to be 250 mg/kg/day.

 

Another study, a Combined Repeat Dose Reproductive/Developmental Toxicity Screening Test according to OECD TG 422 in compliance with GLP is available to assess the repeated dose toxicity of 4-nitrotoluene-2-sulphonic acid (GINC, Japan). In this study, the test substance was administered by gavage to 12 rats per sex and dose of 0, 175, 350 and 700 mg/kg. It was shown that in males and females of the groups of 350 mg/kg or 700 mg/kg respectively, mucosal hyperplasia in the stomach limiting ridge and mucosal atrophy in the cardiac region were seen. Furthermore, in males and females of the 700 mg/kg group, erosion and superficial hemorrhage in the glandular stomach and soft feces with partial black changes were observed. Moreover, males of the 700 mg/kg group exhibited retarded body weight gain, low food consumption, low values for mean corpuscular volume and mean corpuscular hemoglobin, low values for total protein andα1-globulin fraction ratio. In females, of the 700 mg/kg group one animal died and one animal was sacrificed in extremis, and also retarded body weight gain was observed.

Under the conditions of this study the NOAEL was determined to be 175 mg/kg/day.

 

 

 

Justification for classification or non-classification

According to the CLP Regulation (EC) No. 1272/2008, substances are classified as specific target organ toxicants following repeated exposure, and are placed in one of two categories, depending on the nature and severity of the effect(s) observed. Substances that have produced significant toxicity in humans or that, on the basis of evidence from studies in experimental animals, can be presumed to have the potential to produce significant toxicity in humans following repeated exposure, are classified in Category 1 for target organ toxicity (repeat exposure). Classification in Category 1 is applicable when significant toxic effects are observed in a 90-day repeated-dose animal study at low concentrations (< 10 mg/kg bw/day in oral studies, and < 20 mg/kg bw/day in dermal studies) (CLP Regulation (EC) No. 1272/2008: Annex 1, Part 3, Table 3.9.2).
Substances which can be presumed to have the potential to be harmful to human health following repeated exposure, based on evidence from animal studies, are classified in Category 2. Classification in Category 2 is applicable when significant toxic effects are observed in a 90-day repeated-dose animal study at generally moderate exposure concentrations (10 to 100 mg/kg bw/day in oral studies, and 20 to 200 mg/kg bw/day in dermal studies) (CLP Regulation (EC) No. 1272/2008: Annex 1, Part 3, Table 3.9.3).

Based on the sub-chronic, oral NOAEL value of 250 mg/kg bw/day in rats, no classification of the test item is warranted for specific target organ toxicity – repeated exposure according to the CLP Regulation (EC) No. 1272/2008.

 

Based on the experimental evidences in the assessment of the toxicity potential after repeated oral exposure, the test item does not need to be classified according to the CLP Regulation (EC 1272/2008).