4-Methylsulfonyl-2-nitro benzoic acid

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed OECD and GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-methanesulfonyl-2-nitrobenzoic acid

EC Number:

601-017-1

Cas Number:

110964-79-9

Molecular formula:

C8 H7 N1 O6 S1

IUPAC Name:

4-methanesulfonyl-2-nitrobenzoic acid

Details on test material:

- Name of test material (as cited in study report): MNBA (2-nitro-4-methylsulphonylbenzoic acid)
- Physical state: Solid
- Analytical purity: 97.1 % (CORRECTED for purity)
- Lot/batch No.: WRC 15483-30-1
- Storage condition of test material: Ambient temperature in the dark

Test animals

Species:

rat

Strain:

other: Alpk:APfSD

Sex:

male/female

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

The dosing preparations were formulated in corn oil and were found to be suspensions. Each preparation was thoroughly mixed and subdivided into aliquots. Fresh aliquots were used for each day of the study. Further preparations were made at approximately weekly intervals throughout the study.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Representative samples of dosing preparations from the first and third preparations were analysed to verify the achieved concentration of MNBA in corn oil. Samples were taken for the determination of homogeneity at 1.5 and 100 mg/ml (low and high dose levels) in corn oil.
The chemical stability of MNBA in corn oil, stored at room temperature, was determined over a period of at least 12 days prior to the start of the study at concentrations of 1.5 and 100mg /ml.

Duration of treatment / exposure:

The animals were dosed for 28 consecutive days.

Frequency of treatment:

once per day

Doses / concentrations

Remarks:

Doses / Concentrations:
The rats were dosed orally by gavage at 1.0ml/100g according to their daily individual bodyweights.
Basis:
other: 0, 15, 150, 1000 mg/kg/day

No. of animals per sex per dose:

5

Control animals:

yes

Positive control:

not applicable

Examinations

Observations and examinations performed and frequency:

Clinical observations
Prior to the start of the study, all rats were examined to ensure that they were physically normal and exhibited normal activity. Detailed clinical observations were recorded daily. Any rats requiring euthanasia were killed and subjected to an examination post mortem. Any rats found dead were subjected to an examination post mortem as soon as possible after death.
Bodyweights
The bodyweight of each rat was recorded daily, immediately prior to dosing on days 1 to 28 and prior to termination on day 29.
Food consumption
Food consumption was recorded continuously throughout the study.
Functional observational battery
A functional observational battery (FOB) was carried out in week 4.
Motor activity
Locomotor activity was monitored by an automated activity recording apparatus. All animals were tested in week 4.
Clinical pathology
At termination, all rats were bled by cardiac puncture and samples were analysed.
Haematology: red blood cell count, total white cell count, haemoglobin, differential count, haematocrit, platelet count, mean cell volume, mean cell haemoglobin concentration, mean cell haemoglobin. Clotting measurements of prothrombin time and activated partial thromboplastin time with kaolin were made on samples of blood collected into tubes containing trisodium citrate as an anticoagulant. Blood cell morphology, including a differential white blood cell count was assessed by automated methods for all animals.
Blood clinical chemistry
urea, calcium, creatinine, phosphorus (as phosphate), glucose, total bilirubin, albumin, creatinine kinase activity, total protein, alkaline phosphatase activity, cholesterol, aspartate aminotransferase activity, sodium, alanine aminotransferase activity, potassium, gamma-glutamyl transferase activity
chloride

Sacrifice and pathology:

All rats were killed by exsanguination under terminal anaesthesia induced by halothane.
Organ weights: adrenal glands, epididymides, kidneys, thymus, liver, spleen, testes, brain, heart
Macroscopic examination: All animals were subjected to a full examination post mortem.
Tissue submission: abnormal tissue, adrenal gland, brain (cerebrum, cerebellum, medulla and mid brain), caecum, cervix, duodenum, epididymis, femur ( bone marrow), heart, ileum, jejunum, kidney, large intestine, liver, lung, lymph nodes (cervical* and mesenteric), ovary, prostate gland, rectum, sciatic nerve, seminal vesicle, spinal cord, spleen, stomach, testis, thymus, thyroid gland, trachea ,urinary bladder, uterus.
* From terminal kill animals cervical lymph node was not submitted in error. However thymic lymph node was available for the majority of animals and was examined instead.
Microscopic examination: All selected tissues from the control and lOOOmg MNB A/kg/day were examined by light microscopy.

Statistics:

All data were evaluated using the GLM procedure in SAS (1989). Group mean bodyweight data are presented graphically in Figure 1. The differences from control based on the analysis of bodyweight are also presented graphically in Figure 2. The centre of each bar represents the mean percentage difference between control and treated group least-squares means, and the top and bottom of each bar represents the upper and lower 95% confidence limits for this difference A statistically significant difference between the treated group and the control group is present when the bar does not cross the zero difference line. For ease of reference, lines have been added to the plot to show differences of ± 10%.

Results and discussion

Results of examinations

Details on results:

There were no treatment-related clinical observations. There were no effects on bodyweight or clinical observations.
There were no effects on sensory reactivity to stimuli or grip strength. Motor activity was increased in females receiving l000mg/kg/day MNBA during the second half of the observation period but this was considered not to be toxicologically significant
There were no toxicologically significant changes in haematology or clinical pathology parameters. There were no changes on organ weights or macroscopic or microscopic findings that could be attributed to administration of MNBA

Effect levels

Dose descriptor:

NOAEL

Remarks:

(no evidence of toxicity associated with MNBA administration)

Effect level:

> 1 000 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: Up to the highest dose tested (1000 mg/kg bw/day) no signs of substance related adverse effects.

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

There was no evidence of toxicity associated with MNBA administration at dose levels up to and including 1000 mg/kg/day.

Executive summary:

Groups of five male and five female AIpk:APfSD (Wistar-derived) rats were dosed orally by gavage with 0 (control), 15, 150, or l000mg MNBA/kg/day (using corn oil as the control substance and vehicle) for 28 consecutive days. Clinical observations, bodyweights and food consumption were measured throughout the study. In the fourth week of the study the following tests were assessed: sensory reactivity to stimuli; grip strength and motor activity. At the end of the scheduled period, the animals were killed and subjected to an examination post mortem. Cardiac blood samples were taken for clinical pathology, selected organs were weighed and specified tissues were taken for subsequent histopathology examination.

There were no treatment-related clinical observations. There were no effects on bodyweight or clinical observations. There were no effects on sensory reactivity to stimuli or grip strength. Motor activity was increased in females receiving l000mg/kg/day MNBA during the second half of the observation period but this was considered not to be toxicologically significant There were no toxicologically significant changes in haematology or clinical pathology parameters. There were no changes on organ weights or macroscopic or microscopic findings that could be attributed to administration of MNBA.

In conclusion there was no evidence of toxicity associated with MNBA administration at dose levels up to and including 1000mg/kg/day.