4-(4-nitrophenylazo)-2,6-di-sec-butyl-phenol

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD TG 401 and EEC Directive 84/449/EEC, part B.1 and in accordance with the Principles of Good Laboratory Practice (GLP)

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

Remarks:

Concentration, stability and homogeneity of test substance in vehicle were not determined by analytical procedures

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 (Acute Toxicity (Oral))

Deviations:

no

Remarks:

same as above

Principles of method if other than guideline:

not applicable

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

MORTRACE SB CONC.

IUPAC Name:

MORTRACE SB CONC.

Constituent 2

Reference substance name:

4-(4-Nitrophenylazo)-2,6-di- sec.butylphenol

IUPAC Name:

4-(4-Nitrophenylazo)-2,6-di- sec.butylphenol

Constituent 3

Reference substance name:

4-(4-nitrophenylazo)-2,6-di-sec-butyl-phenol

EC Number:

410-610-2

EC Name:

4-(4-nitrophenylazo)-2,6-di-sec-butyl-phenol

Cas Number:

111850-24-9

Molecular formula:

C20 H25 N3 O3

IUPAC Name:

2,6-bis(butan-2-yl)-4-[2-(4-nitrophenyl)diazen-1-yl]phenol

Test material form:

other: dark red-brown liquid

Details on test material:

- Name of test material (as cited in study report): Mortrace SB Conc.
- Physical state: dark red-brown liquid
- Analytical purity: concentrate
- Lot/batch No.: MR 26592 SBC
- Expiry date: June 03, 1993
- Stability under storage conditions: stable
- Stability in vehicle: stability in corn oil not indicated by the sponsor
- Storage condition of test material: at room temperature protected from light

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: BRL Ltd., Basel, Switzerland
- Age at study initiation: approximately 8 weeks
- Fasting period before study: Feed was withheld overnight prior to dosing until approximately 3—4 hours after administration of the test substance.
- Housing: group housed, 5/sex/cage
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days before start of the experiment

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21°C
- Humidity (%): 55%
- Air changes (per hr): 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours light/dark cycle

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE - Corn oil (specific gravity - 0.92)

DOSAGE PREPARATION: In order to melt the test substance completely, it was placed for 3 days in a waterbath at 60°C. Chemical analysis (HPLC) of the test substance after melting revealed that the test substance is stable for 3 days at 60°C.
The formulations were prepared immediately prior to dosing. The test substance was heated to maximally 60°C and subsequently weighed into a glass flask on an analytical balance and the vehicle (w/w) was added. Test substance formulations were heated to maximally 60°C to mix the test material. Adjustment was made for specific gravity of vehicle.
Homogeneity of the test substance in vehicle was obtained by using a spatula and a magnetic stirrer. Concentration of the test substance in vehicle was varied to allow constant dosage volume in terms of ml/kg body weight.
Dose volume: 10 ml/kg body weight

Doses:

2800, 3750 and 5000 mg/kg body weight

No. of animals per sex per dose:

5 male + 5 female rats/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were observed twice daily and the time of death was recorded as precisely as possible. Clinical signs were recorded at periodic intervals on the day of dosing and once daily thereafter, including the time of onset and duration.
Body weights were noted on days 1(pre-administration), 8 and 15 and at death (if found dead after day 1)
- Necropsy of survivors performed: yes

Statistics:

Standard statistical methods were employed

Results and discussion

Preliminary study:

Initially the °Full study” with MORTRACE SB CONC. was started with 5 males and 5 females treated at 3750 mg/kg body weight. Due to the number of deaths, two further groups were selected for the “Full study” and dosed at 5000 and 2800 mg/kg body weight respectively.

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LD50

Effect level:

6 555 mg/kg bw

Based on:

other:

Remarks on result:

other: 95% CL not calculable

Effect levels 2

Sex:

male

Dose descriptor:

LD50

Effect level:

4 960 mg/kg bw

Based on:

other:

Remarks on result:

other: 95% CL not calculable

Effect levels 3

Sex:

female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

other:

Remarks on result:

other: 95% CL not calculable

Mortality:

2800 mg/kg - 1/5 male + 2/5 female
3750 mg/kg - 3/5 male + 2/5 female
5000 mg/kg - 2/5 male + 2/5 female

Clinical signs:

other: Signs of systemic toxicity observed during the study period in each dose group were as follows: 2800 mg/kg body weight: lethargy, hunched posture, uncoordinated movements, rough coat, yellow staining of anus region, orange appearance of urine and faeces 3

Gross pathology:

Macroscopic post mortem examination of the animals that died during the study revealed the following abnormalities in each group:
2800 mg/kg body weight: yellowish discolouration of intestines
3750 mg/kg body weight: red—brown discolouration of stomach contents
5000 mg/kg body weight: yellowish discolouration of the genital region, forestomach, pancreas, intestinal contents and abdominal fat; enlarged stomach with black—brown contents (firm mass); small spleen; enlarged and/or constricted spleen; haemorrhage in thymus

Macroscopic post mortem examination of the surviving animals revealed the following:
2800 mg/kg body weight: no abnormalities
3750 mg/kg body weight: constricted spleen; yellowish discolouration of the genital region and abdominal fat
5000 mg/kg body weight: adherence of the left lateral liver lobe to the spleen and stomach; yellowish discolouration of the genital region and abdominal fat; enlarged and/or constricted spleen

Yellow discolouration of the skin and abdominal organs, and brown staining of stomach contents, may be attributed to staining properties of the test substance and was therefore considered to be of no toxicological significance.

Other findings:

None

Any other information on results incl. tables

None

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Due to the mortality distribution, only estimated oral LD50 values of MORTRACE SB CONE. could be calculated for the sexes combined and for males alone. These were 6555 mg/kg body weight for the sexes combined, and 4960 mg/kg body weight for males alone and > 5000 mg/kg body weight for females.

Executive summary:

The purpose of this study was to assess the toxicity of MQRTPACE SB CONC. when administered to rats as a single oral dose. The study was carried out in accordance with OECD Guideline No. 401, “Acute Oral Toxicity” and EEC Directive 84/449/EEC, Part B.1, 'Acute Toxicity—Oral’. MORTRACE SB CONC. was administered by oral gavage to five rats of each sex per group, at 5000, 3750 and 2800 mg/kg body weight. Animals were subjected tc daily observations and weekly determination of body weight. Macroscopic examination was performed at the end of the experimental period. The incidence of mortality among the sexes combined from high to low dose group, was 4, 5 and 3. Major changes in clinical appearance included lethargy, rough coat, hunched posture and uncoordinated movements. These changes were noted in the majority of animals and had disappeared in all surviving animals by day 7. All animals that died during the study period were noted with body weight loss or very slight body weight gain. Slightly low body weight gain was noted in surviving males over the first week of observation. Body weight gain shown by surviving females over the study period and by surviving males over the second week of observation, was considered to be similar to that expected of normal untreated animals of the same age and strain. Macroscopic post mortem examination of’ the animals that died during the study revealed an enlarged stomach, a small spleen, an enlarged and/or constricted spleen, and a haemorrhage in the thymus. Macroscopic post mortem examination of the surviving animals at termination revealed adherence of a liver lobe to the spleen and stomach, and an enlarged and/or constricted spleen in some animals. Due to the mortality distribution, only estimated oral LD50 values of MORTRACE SB CONC. could be calculated for the sexes combined and for males alone. These were 6555 mg/kg body weight for the sexes combined, and 4960 mg/kg body weight for males alone. Based on the constant mortality ratio of 2/5 in females of all dose groups, the LD50 value for females alone was considered to exceed 5000 mg/kg body weight. Based on these results and according to the EEC criteria for classification and labelling requirements for dangerous substances and preparations (EEC Directive 91/325/EEC, Amendment to Annex VI of the EEC Directive 67/548/EEC), MORTRACE SB CONG. cannot be classified and has no obligatory labelling requirement.