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

Endpoint summary

Description of key information

The oral LD 50 in male/female rats is 6555 mg/kg bw.
Neither mortality nor other severe effects relevant for GHS classification were observed upon administration to rats at 2000 mg/kg bw via the dermal route, hence the LD0 is 2000 and LD 50 >2000 mg/kg bw.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

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)

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

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

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

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

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

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.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

6 555 mg/kg bw

Based on:

other:

Remarks on result:

other: 95% CL not calculable

Sex:

male

Dose descriptor:

LD50

Effect level:

4 960 mg/kg bw

Based on:

other:

Remarks on result:

other: 95% CL not calculable

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

None

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.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

6 555 mg/kg bw

Quality of whole database:

good

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

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 carried out according to OECD Guideline No. 402 and EEC Directive 84/449/EEC, Part B.3 and in accordance with the Principles of Good Laboratory Practices (GLP).

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Remarks:

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

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

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:

yes

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
- Housing: individually housed
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days before start of treatment

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

Type of coverage:

occlusive

Vehicle:

corn oil

Details on dermal exposure:

TEST SITE - The formulation was applied to an area of approximately 25 cm2 (5x5 cm) for males and 18 cm2 (3.5x5 cm) for females by application on a gauze patch fixed successively to aluminium foil and flexible bandage (Coban, 3M, St. Paul, U.S.A.), with drops of petrolatum.

REMOVAL OF TEST SUBSTANCE - 24 hours, after exposure residual test substance was removed with a tissue moistened with tap-water.

DOSE LEVEL - 2000 mg/kg body weight

DOSE VOLUME - 10 ml/kg body weight

VEHICLE - corn oil (specific gravity - 0.92)

TEST MATERIAL TREATMENT AND 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 formulation was 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. The test substance formulation was 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 by stirring.

Duration of exposure:

24 hours

Doses:

2000 mg/kg body weight

No. of animals per sex per dose:

5 males + 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14
- Frequency of observations and weighing: Animals were observed for mortality twice daily and for clinical signs at periodic intervals on the day of application (day 1) and once daily therafter along with the time of onset and duration. Body weights were recorded on days 1 (pre-administration), 8 and 15
- Necropsy of survivors performed: yes

Statistics:

Standard statistical methods were employed

Preliminary study:

not applicable

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Sex:

male/female

Dose descriptor:

LD0

Effect level:

2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred during the study period

Clinical signs:

other: No signs of ill health or behavioural changes were noted in the animals

Gross pathology:

Macroscopic post mortem examination of the surviving animals at termination revealed scab formation in one male.
Yellow/orange appearance of the dorsal and abdominal skin, as noted in all animals, can be attributed to staining properties of the test substance. Therefore, this finding was considered to be of no toxicological significance.
Renal pelvic dilation was noted in one female. As this finding is commonly noted among rats of this age and strain, it was considered not to have arisen as a result of treatment.

Other findings:

Erythema of the treated skin area was noted in one male on days 13 to 15, and scabs were observed in one male and one female during the second week of observation.
The dorsal and abdominal skin was stained yellow/orange by the test substance in all animals from day 2 onwards. No toxicological significance was attached to this finding.

None

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the study, the dermal LD50 value of MORTRACE SB CONC. in rats of either sex was established as exceeding 2000 mg/kg body weight.

Executive summary:

The purpose of this study was to assess the toxicity of MORTRACE SB CONC. when administered to rats as a single dermal dose. The study was carried out in accordance with OECD Guideline No. 402, “Acute Dermal Toxicity” and EEC Directive 84/449/EEC, Part B.3, “Acute Toxicity — Dermal”. MORTRACE SB CONC. was administered by dermal application, to five rats of each sex, at 2000 mg/kg body weight. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed at the end of the experimental period. No animals died during the study. There were no clinical signs of toxicity or behavioural changes noted over the study period. Low body weight gain was noted among the majority of animals over the first week of the observation period. During week 2 of the study, body weight gain by all animals was considered to be similar to that expected of normal untreated animals of the same age and strain. During the second week of the observation period, erythema of the treated skin area was observed in one male, and scabs were noted in one male and one female. Macroscopic post mortem examination of the surviving animals at termination revealed scabs in one male. In the remaining animals, no abnormalities were noted that were not commonly noted among rats of this age and strain or that were considered toxicologically significant. The dermal LD50 value of MORTRACE SB CONC. in rats of either sex was established as exceeding 2000 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), M0RTRACE SB CONC. cannot be classified and has no obligatory labelling requirement.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

Acute oral toxicity

In the key study using Wistar rats, the 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.

In the supporting study the oral LD50 (sexes combined) of Marker SB in Sprague-Dawley rats was calculated to be 6.60 g/kg body weight with a 95% confidence interval of 5.55 to 8.11 g/kg. The LD50 in male rats was 7.92 g/kg body weight with a 95% confidence interval of 6.15 to 12.45 g/kg and the LD50 in female rats was determined to be 5.50 g/kg body weight with a 95% confidence interval of 4.22 to 7.21 g/kg. From the study report it is not possible to identify whether the test material used in the study included the solvent that Mortrace SB is produced in. Consequently the results of this study are consdered less reliable than those of the more recent study using a Concentrated form of the test material with no solvent.

Based on these data, the LD50 for the sexes combined was chosen as the oral LD50.

Dermal toxicity:

In an OECD guideline 402 acute dermal toxicity study in Wistar rats, the dermal LD50 (both sexes) was determined to be >2000 mg/kg bw.No mortalities occured during the study and observations were limited to evidence of irritation at the site of test material application.

Due to the low bolatility of this substance and the low order of acute toxicity via other routes, the assessment of inhalation toxicity is not required.

Justification for selection of acute toxicity – oral endpoint
GLP guideline study using most representative test material.

Justification for selection of acute toxicity – dermal endpoint
GLP guideline study using most representative test material.

Justification for classification or non-classification

Mortrace SB does not meet the GHS or CLP criteria for classification of acute toxicity.