2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol

Endpoint summary

Description of key information

In an acute oral toxicity study, conducted similar to the OECD-Guideline 401, the oral LD50 in rats was determined to be > 3000 mg/kg body weight (no mortality). In an acute inhalation toxicity study similar to OECD-Guideline 403, the inhalative LC50 was determined to be > 1 mg/l (no mortality). In an acute dermal toxicity study following OECD-Guideline 402 the dermal LD50 was determined to be > 1600 mg/kg body weight (no mortality).

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:

1980-11-19 to 1980-12-02

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

(no data on test material purity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

other: Tif: RAIf (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 7- 8 weeks old
- Weight at study initiation: males: 148 +/- 8.6 g; females: 151 +/- 6.3 g
- Housing: Housing in groups of 5 in Macrolon cages (type 3)
- Diet: ad libitum rat food, NAFAG, Gossau SG
- Water: ad libitum
- Acclimation period: Minimally 4 days
- Fasting period: Overnight

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 55 +/- 10
- Photoperiod (hrs dark / hrs light): 14/10

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Remarks:

(PEG 400)

Details on oral exposure:

VEHICLE
- Amount of vehicle (if gavage): 20 ml/kg bw
- Source: Fluka AG, Buchs SG, Art. 81170
Prior to study a homogenous suspension was generated by dispersion with an Ultra-Turrax. During treatment suspsension was kept stable with a magnetic stirrer.

Doses:

3000 mg/kg bw (technically maximal achievable dose)

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of weighing: Before study, day 7, and day 14
- Necropsy of survivors performed: Yes
- Other examinations performed: Clinical signs and mortality (1, 2, 3, 5 h after application, and daily until to the end of the study (i. e. 14 days))

Statistics:

LD50 values including 95 % confidence limits were calculated by logit model.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 3 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: No mortalities ocurred.

Mortality:

No mortalities occured.

Clinical signs:

other: - Slight sedation up to 5 h after administration of the test material. - Slight dyspnoea up to day 6 after administration of the test material. - Moderate ruffled fur up to 24 h after administration, slight ruffled fur up to day 6 after administration of

Gross pathology:

No substance related gross organ changes were seen.

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral LD50 of the test article in rats of both sexes observed over a period of 14 days is greater than 3000 mg/kg body weight.

Executive summary:

In an oral toxicity study similar to OECD guideline 401, five male and five female rats were dosed once with the test article in PEG400 by gastric intubation at a dose level of 3000 mg/kg body weight and observed for 14 days. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice. No mortalities were recorded. Slight sedation, slight dyspnoea, slight curved body position and slight to moderate ruffled fur was observed after administration of the test material. The animals recovered within 7 days. The body weight gain shown by the animals over the study period was considered to be normal. No abnormalities were found at macroscopic post mortem examination of the animals. The oral LD50 value of the test article in Wistar rats was established to exceed 3000 mg/kg body weight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

3 000 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

(only one test concentration, limited data on test material, no data is given on body weight development)

GLP compliance:

no

Test type:

standard acute method

Species:

rat

Strain:

other: Tif. RAI

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Bred under SPF conditions in companies own breeding unit
- Age at study initiation: 8 - 9 weeks
- Weight at study initiation: 195 - 205 g
- Housing: Males and females were segregated and kept in Macrolon cages, type 4 (9 animals to a cage)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 1
- Humidity (%): 50

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: ethanol

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: modified version of an apparatus described by Niessen et al., Arch. Toxicol. 20, 44-60 (1963)
- Method of holding animals in test chamber: animals were kept in PVC tubes positioned radially around the exposure chamber.
- Source and rate of air: compressed air (2 atm)
- System of generating aerosols: The liquid was injected by a motor driven syringe at a rate of 60 ml/hr.
- Method of particle size determination: The particle-size distribution in the aerosol was determined gravimetrically on Selectron-Filters, pore size 0.2 ym (Schleicher and Schuell, 8714 Feldbach, Switzerland) every hour with the aid of a "Cascade Impactor" (CT. Casella and Co. Ltd., London N.l, England).

TEST ATMOSPHERE
- Brief description of analytical method used: The aerosol was sampled on membrane filters, pore size 0.2 µm (Sartorius, Göttingen, Germany) in the immidiate vincinity of the animals hourly after the beginning of the test. The concentration of TK-10021 was determined gravimetrically.
- Samples taken from breathing zone: yes

VEHICLE
- Concentration of test material in vehicle (if applicable): 20 %. The output of the spray device and the dimensions of the inhalation chamber are so adjusted to each other, that the solvent evaporates on the way from the nozzle orifice to the rat containers.

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: approximately 5 % > 7 µm, 20 % 3-7 µm, 53 % 1-3 µm, 22 % < 1 µm

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetric filter analysis

Duration of exposure:

4 h

Concentrations:

927 + / - 82 mg/m³, max. technically achievable concentration

No. of animals per sex per dose:

9

Control animals:

no

Details on study design:

- Duration of observation period following administration: 7 days
- Frequency of observations: after 0-4 hrs, 24 hrs, 48 hrs, 7 days
- Necropsy of survivors performed: Yes

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortalitiy occured.

Clinical signs:

other: During the 4-hour exposure and the subsequent 7-day observation period no toxic symptoms were observed.

Body weight:

No data is given.

Gross pathology:

No substance related gross organ changes were seen.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

1 000 mg/m³ air

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:

May 19, 1992 - June 16, 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

(1987-02-24)

Deviations:

yes

Remarks:

(test conducted with 1600 mg/kg bw, the max. technically achievable concentration)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

other: Tif: RAI f1 (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: CIBA-Geigy Ltd., Animal Production, 4332 Stein, Switzerland
- Age at study initiation: Young adult rats
- Weight at study initiation: 225 - 289 g
- Housing: Individual housing in Macrolon cages type 3 with standardised soft wood bedding (Societe Parisienne des Sciures, Pantin, France)
- Diet: ad libitum NAFAG 890 Tox, NAFAG, Gossau/ SG, Switzerland
- Water: ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 55 +/- 10
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Vehicle:

other: 0.5 % (w/v) Carboxymethylcellulose in 0.1 % (w/v) aqueous polysorbate 80

Details on dermal exposure:

TEST SITE
- Area of exposure: Back of the rat
- % coverage: ≥ 10
- Type of wrap: Gauze-lined semi-occlusive dressing fastened around the trunk with an adhesive elastic bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Washing the skin with lukewarm water
- Time after start of exposure: 24 h

VEHICLE
- Amount(s) applied: 4 ml/kg bw
- Concentration: 40 %

OTHER
24 h before study begin an area of the back of the rat was shaved with an electric clipper (at least 10 % of the body surface)

Duration of exposure:

24 h

Doses:

1600 mg/kg bw
Due to the physical-chemical properties, the test substance had to be suspended in a higher vehicle volume (40 instead of 50%). Adhering to guidelines and SOP, and respecting the maximal application volume (4 ml/kg) a limit dose of 1600 mg/kg has been appplied by direct weighing.

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of weighing: Immediately before study begin and on days 7 and 14
- Necropsy of survivors performed: Yes
- Other examinations performed: clinical signs and symptoms (daily for 14 days), mortality (daily: a.m and p.m on working days, a.m. on weekend days)

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 1 600 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred in this study.

Clinical signs:

other: In males and females on application day and the following day slight piloerection was seen. The animals recovered within 2 days.

Gross pathology:

No deviations from normal pathology were found.

Table 1: Body weight in male and female animals after day 0, 7 and 14

Body weight [g]
Males (dose = 1600 mg/kg bw)
animal ID	day 0	day 7	day 14
1	270	306	355
2	259	280	296
3	289	303	345
4	271	292	316
5	276	304	329
mean	273	297	328.2
SD	10.9	11	23.4
Females (dose = 1600 mg/kg bw)
animal ID	day 0	day 7	day 14
1	226	231	236
2	225	232	237
3	238	237	263
4	260	265	277
5	235	257	267
mean	236.8	244.4	256
SD	14.1	15.6	18.5

Interpretation of results:

GHS criteria not met

Conclusions:

Upon an acute dermal administration and a 14 day post-treatment observation period, the LD50 was determined to be > 1600 mg/kg body weight.

Executive summary:

The acute dermal toxicity of the test substance was assessed in a toxicity study following OECD guideline 402 and in compliance with GLP. The test article was administered to five rats of each sex by dermal application at 1600 mg/kg body weight for 24 hours. Higher doses were technically not possible. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice. No mortality occurred. Piloerection was seen, being a common symptom in acute dermal tests. The animals recovered within 2 days. At autopsy, no deviations from normal morphology were found. The dermal LD50 value of the test substance in rats was established to exceed 1600 mg/kg body weight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

1 600 mg/kg bw

Additional information

Acute oral toxicity

The acute oral toxicity of the test substance was determined after a single oral administration to rats. The study was conducted as a limit test similar to OECD Guideline 401. The test substance was suspended in polyethylene glycol and administered once orally via gavage to TIF: RAIf (SPF) rats of both sexes (body weight of the males 148 ±-18.6 and of the females 51 ± 6.3 g, 5 animals each dose group and sex) at a dose of 3000 mg/kg body weight. Prior to treatment the animals adapted to the lab for a minimum of 4 days and fasted over night. The physical conditions and deaths were monitored throughout the whole observation period of 14 days. Slight sedation was observed up to 5 hours and slight dyspnoe occurred up to day 6 after administration of the test material. Up to 24 h after administration the animals showed moderate ruffled fur and slight ruffled fur up to day 6 after administration of the test material; slight curved body position lasted up to day 5 after administration of the test material. The animals recovered within 7 days and the autopsy did not reveal any substance related gross organ changes. No mortality occurred. The oral LD50 was determined to be > 3000 mg/kg body weight (Ciba-Geigy, 1980).

These results are supported by the findings of a second oral toxicity study conducted according to the OECD guideline 401 after single administration of the test substance to hamsters. The test substance was suspended in arachis oil and administered once orally via gavage to Chinese hamsters of both sexes (body weight 24 – 32 g, 5 animals each dose group and sex) at a dose 3000 mg/kg body weight. Prior treatment the animals fasted over night. The physical conditions and deaths were monitored throughout the whole observation period of 14 days. Sedation was observed up to 5 hours after test material administration, dyspnoe up to day 10. Exophthalmus occurred up to day 11 and ruffled fur up to day 8 after dosing. A curved body position lasted up to day 6. The animals recovered within 12 days and the autopsy did not reveal any compound related gross organ changes. No mortality occurred. The oral LD50 was determined to be > 3000 mg/kg body weight (Ciba-Geigy, 1982).

 

Acute inhalation toxicity

The acute inhalation toxicity of the test substance was determined after a single exposure to rat. The study was conducted similar to the OECD-Guideline 403. The test substance was suspended in ethanol and injected as aerosol into the exposure chamber. The output of the spray device and the dimensions of the inhalation chamber were so adjusted to each other that the solvent evaporates on the way from the nozzle orifice to the rat containers. The animals (9 Tif. RAI rats of each sex) were exposed via a nose-only system to a technically maximal achievable analytical substance concentration of 1 mg/l for 4 hours and the particle size distribution was approximately 5 % > 7 µm, 20 % 3-7 µm, 53 % 1-3 µm, 22 % < 1 µm. No clinical symptoms were observed during the 4-hour exposure and the subsequent 7-day observation period. The autopsy did not reveal any compound related gross organ changes. No mortality occurred. The inhalative LC50 was determined to be > 1 mg/l (Ciba-Geigy, 1973).

 

Acute dermal toxicity

The acute dermal toxicity of the test substance was determined after a single exposure to rat. The study was conducted according to the OECD-Guideline 402. 4 ml/kg bw suspension of the test substance in the vehicle (0.5 % (w/v) in carboxymethylcellulose in 0.1 % (w/v) aqueous polysorbate 80) with a final concentration of 1600 mg/kg body weight (i. e. 40%, the maximal technically achievable concentration) were applied to the back of young adult albino rats (body weight 225 - 289 g, 5 animals each sex). The rats were shaved 24 hours prior treatment, whereas the shaved area constituted about 10 % of the total body surface area. After application of the test substance the test site was covered with a gauze-lined semi-occlusive dressing fastened around the trunk with an adhesive elastic bandage. The test compound remained in contact with the skin for 24 hours, until the animals were cleaned with lukewarm water and the exposure sites were examined for local reactions. The animals were observed for 14 days. In males and females at application day and the following day slight piloerection was seen. The animals recovered within 2 days. The body weight gain in male animals was as expected and a reduced bodyweight gain in female rats was observed. The autopsy did not reveal any gross pathology changes. No mortality occurred. The dermal LD50 was determined to be > 1600 mg/kg body weight (Ciba-Geigy, 1992).

According to the physico chemical parameters the test substance is unlikely to be taken up by the dermal route (for reference see toxicokinetics assessment). In support of this assumption the animals did not show any test substance specific clinical signs when exposed to 1600 mg/kg body weight. Together with the LD50 values of greater than 3000 mg/kg body weight observed after oral exposure, it can be assumed that the dermal LD50 will also exceed the theshold for classification (i.e. > 2000 mg/kg).

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data is reliable and suitable for the purpose of classification under Regulation (EC) No.1272/2008. Based on the data, classification for acute toxicity is not warranted under Regulation (EC) No.1272/2008.