2-nitroaniline

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study report, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Principles of method if other than guideline:

This study was designed to assess the toxic effects of ortho-Nitroaniline when administered by inhalation as a vapour or an aerosol /vapour mixture at higher concentrations to 20 CD (Sprague-Dawley derived) rats (10 males/group) for six hours per day, five days per week, for four weeks at target concentrations of 10 and 90 mg/m3. Control animals (10 males) received room-supply air with approximately the same amount of additional nitrogen which was used to generate the 90 mg/m3 (high exposure) test atmosphere.

GLP compliance:

yes

Remarks:

Quality Assurance Statement available; no GLP Compliance Statement available

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-nitroaniline

EC Number:

201-855-4

EC Name:

2-nitroaniline

Cas Number:

88-74-4

Molecular formula:

C6H6N2O2

IUPAC Name:

2-nitroaniline

Details on test material:

- Name of test material (as cited in study report): o-nitroaniline
- Analytical purity: ca. 100%
- Lot/batch No.: 1769188

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: 56 days
- Weight at study initiation: mean 268 g (253-275 g)
- Housing: one/cage
- Diet (ad libitum): Purina Rodent Laboratory Chow - 5001
- Water (ad libitum): tap water

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

air

Remarks on MMAD:

MMAD / GSD: - Low exposure chamber: average aerodynamic count median diameter = 0.55, standard deviation = 2.1
- High exposure chamber: average aerodynamic count median diameter = 3.6 , standard deviation = 2.7

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure chamber: stainless steel and glass chamber with a total volume of one cubic meter (m3) and an effective volume of 760 liters (L)
- System of generating particulates/aerosols:
To generate levels of 10 and 90 mg/m3 ortho-Nitroaniline, the material was placed in a 2000 mL three-necked flask with a center well. Both flasks were placed in a paraffin oil bath maintained at 110 °C (by a Hamilton Beach Automatic Oven Roaster, Inh, 02). A glass "T" tube was connected to each flask and was fitted into the horizontal inlet portal of the 1 m3 chamber with a rubber stopper. A heating tape was wrapped around the "T" tubes to mlnimize substance condensation. Nitrogen was administered at approximately 3 lpm or 15 lpm to two bubblers to generate the 10 and 90 mg/m3 test substance levels, respectively. In addition, a copper coil immersed in the oil bath was used to pre-heat the nitrogen. The resultant vapour was diluted with room-supply air at the side arm of the "T" tube and was directed into the exposure chambers.
- Temperature, oxygen concentration in air chamber: 26-27 °C, 19.2-20.7%
- Air flow rate: dynamical operation; average air flow rate of 219 liters per minute (lpm). This flow rate was calculated to provide one complete air change every 4.6 minutes and a 99% equilibrium time of 21 minutes.
- Method of particle size determination: Measurements of particlesize distribution were performed three times during the first week of study and once per week thereafter for all test groups using a Royco Particle Monitor.


TEST ATMOSPHERE
The generation apparatus and test material or vehicle were weighed before and after each exposure. The difference in weight represented the amount of material delivered during the exposure, this value divided by the total volume of air delivered in the exposure yielded the nominal exposure concentration.
- Brief description of analytical method used: Hitachi 100-40 UV Spectrophotometer
- Samples taken from breathing zone: yes

VEHICLE

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

6 hours/day, 5 days/week, 4 weeks

Frequency of treatment:

5 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0.0098 and 0.093 mg/L
Basis:
analytical conc.

No. of animals per sex per dose:

10

Control animals:

yes, sham-exposed

Positive control:

no

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once/week

BODY WEIGHT: Yes
- Time schedule for examinations: Individual body weights were recorded on Day 1 (prior to exposure), on Test Days 3, 10, 17, 24 and at termination (fasted).

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at termination
- Anaesthetic used for blood collection: No
- Animals fasted: Yes
- How many animals: all
- Parameters: methemoglobin, hemoglobin, hematocrit, erythrocyte count, clotting time, leukocytes (total and differential), red cell morphology, reticulocytes

CLINICAL CHEMISTRY: No

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes


Organ weights:
- gonads (testes with epididymides, paired), brain

Statistics:

Body weights, hematology and clinical chemistry parameters, organ weights, and organ/body weight ratios were statistically evaluated. Mean values for the treatment groups were compared to the control group to detect statistically significant differences.

Results and discussion

Results of examinations

Details on results:

CLINICAL SIGNS AND MORTALITY
All animals survived the duration of the study.
An increased incidence of secretory responses (lacrimation, mucoid nasal discharge and/or dried red nasal dlscharge) was exhibited by the animals
of both treated groups in relation to the control animals. The incidence of secretory responses was higher during the latter weeks of the study for the
treated animals. In addition, all of the low and high exposure animals exhibited yellow fur at all four examination intervals.

BODY WEIGHT AND WEIGHT GAIN
Body weight data were considered unremarkable.

HAEMATOLOGY
The percent methemoglobin for the high-exposure animals was statistically (P< 0.05) increased as compared to the control animal values; however, this change was considered slight and probably, by itself, would not be expected to induce an adverse physiological effect. In addition, hematocrit values for this group were statistically (P< 0.05) increased, while total leukocyte counts were slightly decreased as compared to control animals. Inspecti on of the differential leukocyte results indicated that the absolute values for segmented neutrophils of the high-exposure animals were statistically
(P< 0.05, Dunnett's Test) decreased as compared to controls. The hematocrit and leukocyte findings are considered marginal, as the value for individual test animals overlap with the individual control animals values; further, the means are w ithin both historical and biologically acceptable ranges.

ORGAN WEIGHTS
Terminal organ and body weights and organ/body weight, organ/brain weight ratios were considered unremarkable for the brain and testes with
epididymides.

GROSS PATHOLOGY / HISTOPATHOLOGY: NON-NEOPLASTIC
Gross postmortern observations of the testes and epididymides of all rats were considered unremarkable. Testicular degeneration was noted in one
control (1/10) and one high-exposure (1/10) rat. Sperm granuloma in the epididymis was present in one high-exposure rat (1/10). These microscopic changes were not considered to be related to treatment with the test material.

Effect levels

1

Dose descriptor:

NOAEC

Effect level:

0.01 mg/L air (analytical)

Based on:

test mat.

Sex:

male

2

Dose descriptor:

LOAEC

Effect level:

0.093 mg/L air (analytical)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: secretory responses, haematology

Target system / organ toxicity

Critical effects observed:

not specified