Reaction mass of 4-tert-butyl-2,5-xylenol and 6-tert-butyl-2,4-xylenol

Endpoint summary

Description of key information

Oral: Key study: Experimental result: Test according to OECD guideline 423 and EU method B.1 tris. GLP study.

LD50 >300 and < 2000 mg/kg bw (female)

Dermal: Key study: Experimental result: Test according to OECD guideline 402 and EU method B.3. GLP study.

LD50  > 2000 mg/kg bw (rat, male/female)

Dermal: Key study: Experimental result: Test according to OECD guideline 402 and EU method B.3. GLP study.

LD50 = 205 mg/kg bw (rabbit, male/female)

Inhalation: Data waiving: In accordance with column 2 of REACH Annex VIII, the study does not need to be conducted since exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size.

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:

2010-01-26 to 2010-02-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Meets the requirements of GLP. There are no deviations from the recommended guideline.

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Sprague Dawley rats (SPF Caw) originated from Elevage JANVIER (53940 Le Genest St Isle - France)
- Age at study initiation: 8 or 9 weeks old
- Weight at study initiation: 184 g and 232 g
- Fasting period before study: food was removed at D-1 and then redistributed 4 hours after the test item administration
- Housing: housed by group of three in solid-bottomed clear polycarbonate cages with a stainless steel mesh lid. Each cage contains sawdust bedding which was changed at least 2 times a week.
- Diet: foodstuff (M20-SDS) was supplied freely. Food was removed at D-l and then redistributed 4 hours after the test item administration.
- Water (e.g. ad libitum): tap-water from public distribution system was supplied freely. Microbiological and chemical analyses of the water were carried out once every six months by the IPL, Santé, Environnement Durables - Atlantique.
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%):30 to 70%
- Air changes (per hr): approximately fifteen changes per hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (07.00 to 19.00) and twelve hours darkness

Route of administration:

oral: gavage

Vehicle:

olive oil

Details on oral exposure:

Group treated with 300 mg/kg (step 1 and 2):

VEHICLE
- Concentration in vehicle: 300 mg/kg
- Amount of vehicle (if gavage): 1.79 mL

MAXIMUM DOSE VOLUME APPLIED: 2.1 mL/kg body weight

Group treated with 2000 mg/kg (step 3):

NO VEHICLE
- Concentration: 2000 mg/kg

MAXIMUM DOSE VOLUME APPLIED: 2.1 mL/kg body weight

Doses:

300 mg/kg bw and 2000 mg/kg bw

No. of animals per sex per dose:

300 mg/kg bw: 6 females
2000 mg/kg bw: 3 females

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Systematic examinations (list of symptoms, recorded as "present" or "absent" ) were carried out to identify any behavioural or toxic effects on the major physiological functions every day for 14 days or until the death of the animal.
The animals were weighed on day DO (just before administering the test item) then on D2, D7, and D14. Weight changes were calculated and recorded.
- Necropsy of survivors performed: yes, macroscopic observations were entered on individual autopsy sheets

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 - < 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred during the study at 300 mg/kg body weight.
It was noted the death of the three animals treated at 2000 mg/kg body weight, one at 29 hours 45 minutes post-dose and the two others at about 48 hours post-dose.

Clinical signs:

other: No clinical signs related to the administration of the test item were observed at the 300 mg/kg bw group. The mortalities at the 2000 mg/kg bw group were preceded by a decrease in spontaneous activity (313) and in rightiug reflex (113) and by a bradypnea

Gross pathology:

The macroscopical examination of the animals at the end of the study revealed a white thickness of the forestomach in three animals (3/6).
The macroscopical examination of the dead animals revealed a red thinning (2/3) or a red coloration (1/3) of the forestomach, associated or not with black spots on the forestomach (1/3) and a thinning of the corpus (2/3), associated or not with black spots on the corpus (1/3).

Interpretation of results:

other: Category 4 (CLP Regulation EC no. 1272/2008)

Conclusions:

The LD50 of the test item is higher than 300 mg/kg body weight and lower than 2000 mg/kg body weight by oral route in the rat.

Executive summary:

The test item was administered to a group of 6 female Sprague Dawley rats at the single dose of 300 mg/kg body weight and to a group of 3 female Sprague Dawley rats at the single dose of 2000 mg/kg body weight. The experimental protocol was established according to the official method as defined in the O.E.C.D. guideline N° 423 and the test method B.lter of the Council regulation N°440/2008. No mortality occurred during the study at 300 mg/kg body weight. No clinical signs related to the administration of the test item were observed. The body weight evolution of the animals remained normal throughout the study. The macroscopical examination of the animals at the end of the study revealed a white thickness of the forestomach in three animals (3/6). It was noted the death of the three animals treated at 2000 mg/kg body weight, one at 29 hours 45 minutes post-dose and the two others at about 48 hours post-dose. The mortalities were preceded by a decrease in spontaneous activity (3/3) and in righting reflex (1/3) and by a bradypnea (3/3), a partial ptosis (3/3), and a staggering gait (3/3) on the first day of the study. At 24 hours post-dose, it was noted a decrease in spontaneous activity (3/3), in body temperature (1/3) and in muscle tone (3/3), an absence of Preyer's reflex (3/3) and of righting reflex (2/3), a bradypnea (3/3), a partial ptosis (2/3), mydriasis (2/3),anincreased lachrymation (3/3) and a piloerection (3/3). The macroscopical examination of the dead animals revealed a red thinning (2/3) or a red coloration (1/3) of the forestomach, associated or not with black spots on the forestomach (1/3) and a thinning of the corpus (2/3), associated or not with black spots on the corpus (1/3). In conclusion, the LD50 of the test item is higher than 300 mg/kg body weight and lower than 2000 mg/kg body weight by oral route in the rat. In accordance with the OECD guideline n°423, the LD50 cut-off of the test item may be considered as 500 mg/kg body weight by oral route in the rat.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Klimisch 1. This study was carried out in accordance with internationally valid GLP principles.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of REACH Annex VIII, the study does not need to be conducted since exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size.

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 November 2007 - 11 December 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Meets the requirements of GLP. There are no deviations from the recommended guideline.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

Himalayan

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: LPT Laboratory of Pharmacology and Toxicology GmbH & Co. KG branch Löhndorf 24601 Löhndorf/Post Wankendorf, Germany
- Age at study initiation: approx. 3.5 - 9 months
- Weight at study initiation: Males: 2.1 - 3.0 kg; Females: 2.1 - 2.9 kg
- Housing: singly in cages with dimensions of 380 mm x 425 mm x 600 mm
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: At least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20°C ± 3°C
- Humidity (%): 55% ± 15%
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light (

Type of coverage:

semiocclusive

Vehicle:

water

Remarks:

(Aqua ad iniectabilia)

Details on dermal exposure:

TEST SITE
- Area of exposure: shaved intact dorsal skin
- % coverage: approx. 15 cm x 15 cm, 1/10 of body surface
- Type of wrap if used: The gauze was covered with a plastic sheet and secured with adhesive plaster on the application site.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): At the end of the exposure period no residual item had to be removed.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.469 mL/kg b.w.

VEHICLE
Aqua ad iniectabilia for the dose levels of 50 and 200 mg/kg b.w.
Used as supplied for the dose level of 450 mg/kg b.w.

Duration of exposure:

24 hours

Doses:

50, 200 and 450 mg/kg b.w.

No. of animals per sex per dose:

3 animals per sex and per dose.

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations were performed before and immediately, 5, 15, 30 and 60 min, as well as 3, 6 and 24 hours after administration. All surviving animals were observed for a period of 14 days (at least once per day). Individual body weights were recorded before administration of the test item and thereafter in weekly intervals up to the end of the study and at death.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:
Clinical signs: changes of skin and fur, eyes and mucous membranes, respiratory and circulatory function, autonomic and central nervous system and somatomotor activity and behaviour pattern, tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma. The skin was observed for the development of erythema and oedema and was rated according to OECD 404.
Body weight: Individual body weight, changes in weight.
Necropsy: All gross pathological changes were recorded.

Statistics:

The LD50 was calculated according to FINNEY (Probit analysis).

Sex:

male/female

Dose descriptor:

LD50

Effect level:

205 mg/kg bw

Based on:

test mat.

Remarks on result:

other: recalculated for the substance from LD50 = 150 mg/kg b.w.

Mortality:

A single dermal administration of 450 mg/kg b.w. caused death in all 3 of 3 male and 3 of 3 female animals within 24 hours after administration.
A single dermal administration of 200 mg/kg b.w. caused death in all 3 of 3 male and 2 of 3 female animals within 48 hours after administration.
A single dermal administration of 50 mg/kg b.w. did not reveal any signs of toxicity. No mortality did occur.

Clinical signs:

other: No clinical signs were observed.

Gross pathology:

No pathological findings.

Other findings:

No skin reactions were observed.

Interpretation of results:

other: Category 3 (CLP Regulation EC no. 1272/2008)

Conclusions:

The LD50 was determined to be 205 mg/kg b.w. by dermal route in rabbits.

Executive summary:

An acute dermal toxicity study in rabbits was performed according to EU method B3 and OECD Guideline 402 (GLP study). 3 rabbits per sex and dose were exposed to dose levels of 50, 200 and 450 mg/kg b.w. The test item was applied once for 24 hours on the shaved intact dorsal skin of rabbits (approx. 15 cm x 15 cm, 1/10 of body surface). This treatment was followed by an observation period of 2 weeks. Under the test conditions, a single dermal administration of 450 mg/kg b.w. caused death in all 3 of 3 male and 3 of 3 female animals. All animals died prematurely within 24 hours after administration. A single dermal administration of 200 mg/kg b.w. caused death in all 3 of 3 male and 2 of 3 female animals. These animals died prematurely within 48 hours after administration. A single dermal administration of 50 mg/kg b.w. did not reveal any signs of toxicity. No mortality did occur. All surviving animals gained the expected body weight throughout the whole study period. No clinical signs non skin reactions were observed. No pathological findings were recorded. The LD50 of the test item was determined to be 150 mg/kg b.w. Based on these results the LD50 for the substance reaction mass of 2-tert-butyl-4,6-dimethylphenol and 4-tert-butyl-2,5-dimethylphenol was determined to be 205 mg/kg b.w. by dermal route in rabbits.

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 26 January to 09 February 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Meets the requirements of GLP. There are no deviations from the recommended guideline.

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Elevage JANVIER (53940 Le Genest St Isle -France)
- Age at study initiation: 8 weeks old (male) and 9 weeks old (female)
- Weight at study initiation: 280-297 g (male) and 232-252 g (female)
- Housing: during the treatment, the animals were kept in individual cage. At D3, the animals were put into their cage by 2 or 3.
- Diet (e.g. ad libitum): foodstuff was supplied freely
- Water (e.g. ad libitum): drinking water (tap-water from public distribution system) was supplied freely
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%): 30 to 70%
- Air changes (per hr): approximately fifteen changes per hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (07.00 to 19.00) and twelve hours darkness

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- % coverage: at least 10 per cent of the body surface area was clear for the application of the test item
- Type of wrap if used: porous gauze dressing

REMOVAL OF TEST SUBSTANCE
- Washing (if done): with distilled water
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2.1 mL/kg body weight
- Constant volume or concentration used: yes

Duration of exposure:

24 hours

Doses:

2000 mg/kg body weight

No. of animals per sex per dose:

5 males and 5 females

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Systematic examinations were carried out to identity any behavioural or toxic effects on the major physiological functions 14 days after administration of the test item.
This examination focuses particularly on a list of symptoms, recorded as "present" or "absent" on the observation sheet.
These observations were compared to historical control data.
Observations and a mortality report were then carried out every day for 14 days.
The animals were weighed on day DO (just before administering the test item) then on D2, D7, and D14.
Weight changes were calculated and recorded.
- Necropsy of survivors performed: yes
On D14, the animals were anaesthetised with sodium pentobarbital and administration continued to fatal levels. Macroscopic observations were entered on individual autopsy sheets.
Only those organs likely to be modified in cases of acute toxicity were examined. No organ was removed and preserved in view to microscopic examinations.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred during the study.

Clinical signs:

other: No systemic clinical signs related to the administration of the test item were observed. An erythema was noted on the treated area of all females on day 1 and day 2, and on two females on day 3 and day 10. This erythematous reaction was associated with dr

Gross pathology:

The macroscopical examination of the animals at the end of the study did not reveal treatment-related changes.

Interpretation of results:

other: (CLP Regulation EC no. 1272/2008)

Conclusions:

The LD50 of the test item is higher than 2000 mg/kg body weight by dermal route in the rat.

Executive summary:

The test item was applied onto the intact skin of 10 Sprague Dawley rats (5 males and 5 females) at the single dose of 2000 mg/kg body weight. The experimental protocol was established on the basis of the official method as defined in the O.E.C.D. guideline N° 402 and the test method B.3 of the Council regulation No 440/2008. No mortality occurred during the study. No systemic clinical signs related to the administration of the test item were observed. An erythema was noted on the treated area of all females on day 1 and day 2 and on two females on day 3 and day 10. This erythematous reaction was associated with dryness in three females on day 2, which remained on day14 inone female. Presence of scab was noted in two females between day 3 and day 9. An erythema was noted on the treated area of all males on day 1 and day 2 and in two males on day3. Adryness was noted in all males between day 3 and day 6. The body weight evolution of the animals remained comparable between treated and control animals throughout the study. The macroscopical examination of the animals at the end of the study did not reveal treatment-related changes. In conclusion, the LD50 of the test item is higher than 2000 mg/kg body weight by dermal route in the rat.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

205 mg/kg bw

Quality of whole database:

Two studies are available, one in rats and other in rabbits. Both studies were carried out in accordance with internationally valid GLP principles (Klimisch 1).

Additional information

Oral: Key study: Experimental result: Test according to OECD guideline 423 and EU method B.1 tris.

The test item was administered to a group of 6 female Sprague Dawley rats at the single dose of 300 mg/kg body weight and to a group of 3 female Sprague Dawley rats at the single dose of 2000 mg/kg body weight.The LD50 of the test item is higher than 300 mg/kg body weight and lower than 2000 mg/kg body weight by oral route in the rat.

 

Dermal: Key study: Experimental result: Test according to OECD guideline 402 and EU method B.3.

The test item was applied onto the intact skin of 10 Sprague Dawley rats (5 males and 5 females) at the single dose of 2000 mg/kg body weight. The LD50 of the test item is higher than 2000 mg/kg body weight by dermal route in the rat.

Dermal: Key study: Experimental result: Test according to OECD guideline 402 and EU method B.3.

3 rabbits per sex and dose were exposed to dose levels of 50, 200 and 450 mg/kg b.w. The test item was applied once for 24 hours on the shaved intact dorsal skin of rabbits. This treatment was followed by an observation period of 2 weeks. The LD50 was determined to be 205 mg/kg b.w. by dermal route in rabbits.

Inhalation: Data waiving: In accordance with column 2 of REACH Annex VIII, the study does not need to be conducted since exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size.

 

Justification for selection of acute toxicity – oral endpoint

Only one study available.

Justification for selection of acute toxicity – dermal endpoint

The lowest value was selected.

Justification for classification or non-classification

The oral LD50 was between 300 and 2000 mg/kg bw. Therefore, the substance is classified as Acute Toxicity Category 4.

The lowest dermal LD50 was 205 mg/kg bw. Therefore, the substance is classified as Acute Toxicity Category 3.