2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-(3-((2-ethylhexyl)oxy)-2-hydroxypropoxy)phenol

Endpoint summary

Description of key information

In a 28 d study performed in rat (GLP-compliant, OECD guideline 407), the substance did not cause mortalities, signs of toxicity or any other changes or abnormalities. The NOEL/NOAEL is considered to be 1000 mg/kg bw/d.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sept - Oct 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Version / remarks:

1981-May-12

Deviations:

no

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Batch No.of test material: Z 2759
- Expiration date of the lot/batch: Sep 1997
- Purity: 99.3%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: In the original container at room temperature away from direct sunlight.
- Solubility and stability of the test substance in the solvent/vehicle: Stable in corn oil (vehicle) for at least 48 hours

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
The test item was weighed into a glass beaker on a tared Mettler balance and the vehicle added. The mixtures were prepared using an ultra turrax.
Homogeneity of the test article in the vehicle was maintained during treatment using a magnetic stirrer (daily preparation prior to each treatment)
-Stable in corn oil for at least 48 hours

FORM AS APPLIED IN THE TEST (if different from that of starting material) : Solution

Species:

rat

Strain:

other: Hanlbm:WIST (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: BRL, Biological Research Laboratories Ltd. Wolferstrasse 4 4414 Fuellinsdorf/Switzerland
- Age at study initiation: 6 weeks
- Weight at acclimatization: Males: 121 - 157 g (mean 142 grams), Females: 111 - 142 g (mean 128 grams)
- Housing: Groups of five in Makrolon type-4 cages with standard softwood bedding ('Lignocel' Schill AG, 4132 Muttenz / Switzerland).
- Diet (e.g. ad libitum): Pelleted standard Kliba no. 343 rat maintenance diet (KLIBA Muhlen AG, 4303 Kaiseraugst/Switzerland) was available ad libitum (Batch no. 78/96 ). The feed batch was analyzed for contaminants.
- Water (e.g. ad libitum): Tap water was available ad libitum in water bottles
- Acclimation period: 7 days under test conditions following a health examination. Only animals without any visible signs of illness were used for the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22+/- 3
- Humidity (%): 40-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12

IN-LIFE DATES:
Delivery of Animals 02-SEP-1996
Acclimatization/Pretest 02-SEP-1996 to 08-SEP-1996
Administration/Treatment 09-SEP-1996 to 06-OCT-1996
Recovery 07-0CT-1996 to 20-0CT-1996
Termination Allocation A animals: 07-OCT-1996
Allocation B animals: 21-0CT-1996

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Solution preparation by weighing of concentration dependent test item amount with the vehicle

RATIONALE:
Accidental oral ingestion is a possible route of human exposure.

VEHICLE
- Amount of vehicle (if gavage): 10 ml/kg bw/d

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Concentration, homogeneity and stability of the test article/vehicle mixtures were determined on samples taken during acclimatization and during week 3 of the treatment. The analyses were performed in the Analytical Laboratories according to a method supplied by the sponsor.
At acclimatization: 04-SEP-1996, 06-SEP-1996
At 3 weeks: 25-SEP-1996

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily

Dose / conc.:

50 mg/kg bw/day (nominal)

Dose / conc.:

200 mg/kg bw/day (nominal)

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

Groups 1 and 4: 10 males; 10 females (0 and 1000 mg/kg bw)
groups 2 and 3: 5 males and 5 females (50 and 200 mg/kg bw)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
Based upon data from an acute toxicity study and the results of a 5-day dose-range-finding study in which the test article was administered by gavage to 3 rats per group and sex. Treatment with test article at 0, 200 and 1000 mg/kg resulted in the following findings: Relative kidneys weight of males treated at 1000 mg/kg was statistically significant higher (10 %) when compared with the controls.

- RECOVERY:
14 d

- IDENTIFICATION:
Cage card and individual ear tattoo

- RANDOMIZATION:
Computer-generated random algorithm

Positive control:

not required

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Not specified

DETAILED CLINICAL OBSERVATIONS:
Observations for mortality/viability were recorded twice daily and clinical signs of toxicity were recorded at least once daily.

BODY WEIGHT:
Body weights were recorded weekly during pretest, treatment and recovery and before necropsy.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- The food consumption was recorded once during the pretest period and weekly thereafter using an on-line electronic recording system consisting of a Mettler balance connected to the RCC computer.
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Not specified

FOOD EFFICIENCY:
- 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: Not specified

OPHTHALMOSCOPIC EXAMINATION: Yes
- at 4 weeks; at 6 weeks
- Dose groups that were examined: All animals

HAEMATOLOGY: Yes
- after 4 and 6 weeks, Blood samples were collected between the hours of 06.20 and 07.35 to reduce biological variation caused by circadian rhythms.
- Anaesthetic used for blood collection: No
- Animals fasted: Yes, animals were fasted in metabolic cages for approximately 18 hours before blood sampling but allowed access to water ad libitum.
- How many animals: All animals
- Parameters checked in table 1 were examined

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: After 4 weeks; after 6 weeks
- Animals fasted: Yes
- How many animals: All animals
- Parameters checked in table 3 were examined

URINALYSIS: Yes
- Date: 07-OCT-1996, 21-0CT-1996, Blood samples were collected between the hours of 06.20 and 07.35 to reduce biological variation caused by circadian rhythms.
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes, animals were fasted in metabolic cages for approximately 18 hours before blood sampling but allowed access to water ad libitum.
- Parameters checked in table 2 were examined.

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Statistics:

The following statistical methods were used to analyze the body weights, organ weights all ratios as well as clinical laboratory data:
When the variables could be assumed to follow a normal distribution, the Dunnett-test (many to one t-test) based on a pooled variance estimate was applied for the comparison between the treated groups and the control groups for each sex.
The Steel-test (many-one rank test) was applied when the data could not be assumed to follow a normal distribution. The Fisher's exact test was applied to the ophthalmoscopy data.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: absence of adverse effects

Critical effects observed:

no

Conclusions:

The oral administration of the test substance to Wistar rats at doses of 50, 200 and 1000 mg/kg/day, for 28 days, resulted in no effects on mortality, clinical signs, food consumption, body weight, ophthalmoscopic examinations, organ weights, hematology, clinical biochemistry, urinalysis, macroscopic and microscopic findings.
Based on the results of this study, 1000 mg/kg of the test article was established as the no-observed-adverse-effeet-level (NOAEL) and as the no-observed- effect-level (NOEL).

Executive summary:

In this subacute toxicity study, the test substance was administered daily by oral gavage to SPF-bred Wistar rats of both sexes at dose levels of 0, 50, 200 and 1000 mg/kg body weight/day for a period of 28 days. The study comprised 5 animals per group and sex which were sacrificed after 28 days of treatment. Additional 5 rats per sex and group were used at 0 and 1000 mg/kg. These animals were treated for 28 days and then allowed a 14-day treatment-free recovery period after which they were sacrificed. Clinical signs, food consumption and body weights were recorded periodically during the treatment and recovery periods. Ophthalmoscopic examinations were performed at the end of the treatment and recovery periods. At the end of the dosing period and the treatment-free period, blood samples were withdrawn for hematology and plasma chemistry analyses, and urine samples were collected for biochemical and microscopic analyses. All animals were killed, examined post mortem and necropsied. Samples of major organs from all group 1 (0 mg/kg) and group 4 (1000 mg/kg) animals, as well as gross lesions from all animals were processed as hematoxylin and eosin stained slides and examined by light microscopy. The results of the study are summarized as follows:

Mortality: All animals survived the scheduled treatment period.

Clinical Signs: There were no test article-related clinical signs in any group.

Body Weight: There was no effect on body weight.

Food Consumption / Relative Food Consumption: There were no effects on food consumption or relative food consumption.

Ophthalmoscopic Examinations: There were no treatment-related changes on the ophthalmological findings.

Hematology / Clinical Biochemistry / Urinalysis: There were no treatment-related effects on hematology, clinical biochemistry and urinalysis data at termination of the treatment nor at the end of the treatmentfree recovery period which could be considered of toxicological significance.

Organ Weights and Organ Weight Ratios: There were no treatment-related changes in organ weights and ratios.

Macroscopic and Microscopic Findings: All gross and microscopic lesions reorded in this study were considered to be spontaneous in origin. Their incidence and severity was similar in control and treated rats. There was no morphologic evidence of toxicity to test article.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

GLP-compliant OECD study

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

A 28d study in rats (OECD guideline 407) was performed to evaluate the toxicity of the test substance after repeated application.

The test article was administered daily by oral gavage to SPF-bred Wistar rats of both sexes at dose levels of 0, 50, 200 and 1000 mg/kg body weight/day for a period of 28 days. The study comprised 5 animals per group and sex which were sacrificed after 28 days of treatment. Additional 5 rats per sex and group were used at 0 and 1000 mg/kg. These animals were treated for 28 days and then allowed a 14-day treatment-free recovery period after which they were sacrificed. Clinical signs, food consumption and body weights were recorded periodically during the treatment and recovery periods. Ophthalmoscopic examinations were performed at the end of the treatment and recovery periods. Haematology, urinalysis as well as pathological and microscopic analysis were performed.

All animals survived the scheduled treatment period. There were no test article-related clinical signs in any group. Body weight and food consumption were unaffected by the test substance. There were no treatment-related effects on hematology, clinical biochemistry and urinalysis, neither at termination of the treatment nor at the end of the treatment free recovery period. All gross and microscopic lesions recorded in this study were considered to be spontaneous in origin. Their incidence and severity was similar in control and treated rats. Changes in organ weight were not observed.

 

Based on the results of this study, 1000 mg/kg of the test article was established as the no-observed-adverse-effect-level (NOAEL) and as the no-observed- effect-level (NOEL).

 

Repeated dose studies via dermal route were not performed. The test article has a logPow of 10 and a molecular weight of 583 g/mol. Thus, the substance is not well absorbed via skin. Additionally, the results of other dermal tests to acute toxicity, irritation and sensitization show that the substance does not cause any reaction to skin. Therefore, toxic effects upon repeated dermal application are unlikely.

 

Repeated dose toxicity after inhalation of the test substance was not investigated as major part of the substance has a particle size of > 40µm (92 %) or more and inhalable particles of < 10 or < 4 µm are not included.

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. There were no significant toxic effects at doses up to 1000 mg/kg bw upon subacute oral exposure in rats. As a result, the substance is not classified for repeated dose toxicity under Regulation (EC) No. 1272/2008, as amended for the thirteenth time in Regulation (EC) No 2018/1480.