3-aminophenol

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Data is from study report

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

The objective of this study was to evaluate the potential toxicity of the test substance, m-aminophenol (batch No. 4090202), when administered daily by gavage to Sprague- Dawley rats for 13 weeks.
The test substance is a dye precursor.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

3-aminophenol

EC Number:

209-711-2

EC Name:

3-aminophenol

Cas Number:

591-27-5

Molecular formula:

C6H7NO

IUPAC Name:

3-aminophenol

Constituent 2

Reference substance name:

m-aminophenol

IUPAC Name:

m-aminophenol

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:
- Age at study initiation: Animals were approximately six weeks old
- Weight at study initiation: had a mean body weight of 190 g for the males (178 g to 207 g) and 173 g for the females (156 g to 190 g).
- Fasting period before study:
- Housing: The animals were housed in suspended wire-mesh cages and each cage contained two rats of the same sex and group. A metallic tray was placed under each cage and contained autoclaved sawdust (SICSA, 94142 Alfortville, France).
- Diet (e.g. ad libitum): The animals had access to AO4 C pelleted diet,
- Water (e.g. ad libitum): The animals had access to bottles containing tap water filtered using a 0.22 micron filter (Millipore S.A., 78140 Velizy, France).
- Acclimation period: A six day acclimatization period to the conditions of the study preceded the beginning of the treatment period.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2 deg C
- Humidity (%): 50 ± 20%
- Air changes (per hr): about 12 cycles/hour of filtered, non-recycled air.
- Photoperiod (hrs dark / hrs light):12h/12h (07:00 - 19:00)

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5 % aqueous methylcellulose

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was administered as a suspension in the vehicle.
Prior to use the vehicle was degassed by sonification for at least ten minutes and was bubbled with nitrogen for two or three minutes; this vehicle was then kept under an argon atmosphere and away from light until use. The test substance was ground to fine powder using a mortar and pestle, suspended in the
vehicle in order to achieve a concentration of 120 mg/ml, and homogenized using a magnetic stirrer. The 4, 14 and 40 mg/ml preparations were prepared by direct dilution of the 120 mg/ml preparation.
The preparations were rapidly inserted in glass sealed bottles under an argon atmosphere. On the basis of stability data, the preparations were made for up to seven days of treatment, except for the 40 mg/ml preparation which was prepared on the day of dosing or the day preceding dosing. The preparations were stored at +4'C, away from light, pending utilization. They were delivered to the animal room each day and maintained under continuous stirring during the dosing procedure.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

PRINCIPLE OF METHODS
Samples of the preparations to be analysed are diluted to a target concentration of 20 microg/mL, using degrassed stabilised solvent. The content of meta-aminophenol is subsequently determined by HPLC with UV detection at 282 nm.

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
20, 70, 200 or 600 mg/kg/day
Basis:
no data

No. of animals per sex per dose:

10 males and 10 females per dose; in total 50 males and 50 females were used.

Control animals:

yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Clinical signs were observed for each animal at least once a day, at the same approximate daily time.

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: once a week

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
The quantity of food consumed by the animals of each cage was recorded once a week (over a seven day period) until the end of the study.

FOOD EFFICIENCY: Yes
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No
- Time schedule for examinations: No data available

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: at the beginning of treatment period and week 13
- Dose groups that were examined: control, 200 and 600 mg/kg/day bw

HAEMATOLOGY: Yes
- Time schedule for collection of blood: approximately 24 hours after treatment
- Anaesthetic used for blood collection: Yes (light ether anaesthesia)
- Animals fasted: Animals were deprived of food and placed in metabolism cages over atleast 14 hours
- Parameters examined: Erythrocytes (RBC), Haemoglobin (HB), mean cell volume (MCV), Packed cell volume (PCV), mean cell haemoglobin concentration (MCHC), mean cell haemoglobin (MHC), thromocytes (PLAT), leucocytes (WBC), differential white cell count with cell morphology (neutrophils, eosinophils, basophils, lymphocytes and monocyes) and reticulocytes (RETIC).


URINALYSIS: Yes
- Time schedule for collection of urine: 13 week
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters examined: Volume, pH, specific gravity (SP.GRAV), proteins (PROT), glucose (GLUC), ketones (CETO), bilirubin (BILI), nitrates (NITR), blood, urobilinogen (UROB) and cytology (leucocytes, erythrocytes, cylinders, magnesium ammonium phosphate crystals, calcium phosphate crystals, calcium oxalate crystals and cells. In addition, appearance and and colour were recorded.


OTHER:
No data available

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
All gross observations were recorded individually. A complete macroscopic examination was performed on all animals that which was killed prematurely. All animals were sacrificed at the end of the treatment period and the weight was recorded for heart, adrenals, kidneys, liver, ovaries, spleen, testes, thymus, thyroids with parathyroids. Paired organs were weighed separately, except thyroids with parathyroids which were weighed together.

Statistics:

Body weight, food consumption, haematology, blood chemistry, urinalysis and organ weight data were subjected to statistical evaluation. The normality of the distibution of the values in each group was checked by Kolmogorov-Smirnov's test. If the distribution was normal, the homogenity of variances between the groups was assessed by Batlett's test or Fisher's test. If no signifcant heterogenicity of the variances was established, the comparison between treated and control groups was performed by Dunnett's test.
If the variance were heterogeneous, the comparison between treated and control groups was performed by Dunn'd test or by Mann Whitney's test.
If the distribution of values in the groups was not normal, the analysiswas repeated after logarithmic transformation of the values (except for organ weights).

It the logarithmic transformation failed to normalise the distribution of the values, comparison of treated and control groups was performed by Dunn's test using original values.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

No clinical signs were observed in animals given 20 mg/kg/day. Ptyalism was observed in some animals given 70 mg/kg/day and in all animals given 200 or 600 mg/kg/day. Lacrimation was observed in some animals given 600 mg/kg/day on week I only.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Slightly lower body weight gain was noted throughout the treatment period in males given 600 mg/kg/day (-19%).

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Slightly lower food consumption was recorded in males given 600 mg/kg/day (-3% to -18% over the period week 4 to week l0). This difference from controls was considered to be treatment-related.

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

The mean efficiency of food utilization of all treated males and females was similar to that of concurrent controls.

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No treatment-related findings were noted at the end of the treatment period.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Signs of slight regenerative anaemia observed at 600 mg/kg.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

On week 13, the following differences from controls were recorded:
Slightly higher total protein level in males given 200 or 600 mg/kg/day, lower potassium level in females given 600 mg/kg/day, slightly higher calcium levels in animals given 600 mg/kg/day, slightly higher total bilirubin and cholesterol levels in animals given 600 mg/kg/day, slightly lower glucose level in females given 200 mg/kg/day and in animals given 600 mg/kg/day, higher cholesterol levels in animals given 600 mg/kg/day, higher inorganic phosphorus concentration in females given 600 mg/kg/day.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Slightly lower urinary pH was noted in males given 600 mg/kg/day and slightly higher urinary volume was observed in males given 200 or 600 mg/kg/day. Colouration of urine was noted in males and females given 200 or 600 mg/kg/day. This observation was attributed to the elimination of the test substance or its metabolites, and was considered to be an indirect proof of the absorption of the test substance.

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Higher absolute and relative spleen weights (related to the higher severity of haemosiderosis) and higher absolute and relative thyroid weights (ascribed to the thyroid hyperactivity) were recorded in animals given 600 mg/kg/day. Higher absolute and relative liver weights were found in animals given 200 or 600 mg/kg/day. Higher relative kidney weights were found in animals given 200 and 600 mg/kg/day, with minimal changes of concurrent absolute weights.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Yellowish deposit on the mucosa of stomach in one male and orange coloured tail in 8/10 females were noted at 600 mg/kg/day. These discolourations were attributed to the properties of the test substance (dye precursor). Blackish colour of the spleen related to the presence of haemosiderosis was observed in some males and females at 200 mg/kg/day and in all animals at 600 mg/kg/day. Large liver (I/1O) or large thyroid glands (I/l0) were observed in males given 600 mg/kg/day.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

When compared to the controls, increase in severity and/or incidence in thyroid hyperactivity was noted in males and females given 70, 200 or 600 mg/kg/day. Haemosiderosis was found in the spleen of animals given 200 or 600 mg/kg/day. Minimal to marked brownish pigment was found in the cortical tubular epithelium of the kidneys in two males at 70 mg/kg/day, in eight males at 200 mg/kg/day and in all males and three females at 600 mg/kg/day. This was considered to be due to the presence of the test substance or its metabolites. Some other minor microscopic findings related to the dyeing properties of the test substance were noted at 200 or 600 mg/kg/day in some organs (orange or brownish pigment laden macrophages in mesenteric lymph nodes and in some parts of the gastro-intestinal tract).

Histopathological findings: neoplastic:

no effects observed

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

70 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

food efficiency

gross pathology

haematology

histopathology: non-neoplastic

mortality

ophthalmological examination

organ weights and organ / body weight ratios

urinalysis

Remarks on result:

other: not specified

Target system / organ toxicity

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

600 mg/kg bw/day (nominal)

System:

other: Overall effects involving multiple systems

Organ:

not specified

Treatment related:

yes

Dose response relationship:

not specified

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

NOAEL for the test chemical was considered at 70 mg/kg bw/day in this 13 -weeks study.

Executive summary:

In this study by L’Oreal (1996), female 6-week-old Sprague-Dawley rats were exposed to 3-aminophenol daily for 13 weeks at 0, 20, 70, 200 and 600 mg/kg bw/day by oral gavage administration. No effects were observed at 20 mg/kg. From 70 mg/kg, there was a dose-related increase in thyroid hyperactivity in both male and females based on microscopic evaluation. At 70 mg/kg, the increase in thyroid function was observed in 2 (of the 10) males and in 2 (of the 10 females). This effect was not considered toxicologically relevant, due to the well-established relationship between increased thyroid hyperactivity and increased functional demand of the liver due to chemical dosing. In comparison to the controls, marked hemosiderosis was noted in the rats treated at 200 mg/kg. This was accompanied by slight changes in biochemistry parameters, i.e. slightly higher total protein levels in blood, slightly lower glucose levels in blood and slightly lower red blood cell count in blood. Based on the data, NOAEL for the test chemical was considered at 70 mg/kg bw/day in this 13 -weeks study.