2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because a pre-natal developmental toxicity study is available

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

No data available; waiving arguments were applied.

Effects on developmental toxicity

Description of key information

No teratogenic effects occurred during reproduction studies from day 6 until day 15 of gestation with rats and mice.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

compared to current guidelines, less parameters were investigated.

GLP compliance:

no

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Obtained from a closed SPF breeding colony.
- Weight at study initiation: 210 g
- Housing: successfully mated females were kept in groups of 5 in Macrolon cages in an air-conditioned room
- Diet: Nafag No. 890
- Water: Tap water

ENVIRONMENTAL CONDITIONS
- Temperature: 20 °C +/- 0.5 °C
- Humidity: 60 +/- 5 %
- Photoperiod: The room was illuminated for 12 hours

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

2 % aqueous solution

Details on exposure:

VEHICLE
- Concentration in vehicle: 2 mL/100g of body weight

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: Mated overnight with males of proven fertility
- M/F ratio: 1 M / 3 F
- Any other information: The day on which spermatozoa were found in the vaginal smear was designated as Day = 0 of pregnancy

Duration of treatment / exposure:

From day 6 until day 15 of gestation, inclusive.

Frequency of treatment:

daily

Duration of test:

21 days

Dose / conc.:

300 mg/kg bw/day (actual dose received)

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

Dose / conc.:

3 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

25 females per dose
25 females for the vehicle controle

Control animals:

yes, concurrent vehicle

Maternal examinations:

BODY WEIGHT: Yes
- Time schedule for examinations: checked daily from day 0 to day 21

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice: On day 21 shortly before delivery
- Organs examined: ovaries and uterus, foetuses

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of corpora lutea: No
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- Examination of the viscera: Yes: According to the slicing technique of Wilson: 1/3 of the foetuses were fixed in a mixture of ethyl aclohol and formol to which acetic acid was added
- Skeletal examinations: Yes: In 2/3 of the foetuses following clearing in potassium hydroxide and staining with Alizarine Red S.

Details on results:

No clearcut reaction to treatment with the test item were noted. The average body-weight gain and the feed consumption were roughly comparable for all groups.

Key result

Dose descriptor:

NOAEL

Effect level:

> 3 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Remarks on result:

other: No adverse effects observed at tested doses

Key result

Abnormalities:

no effects observed

Details on embryotoxic / teratogenic effects:

The gross inspection of the foetuses revealed facial aplasia associated with microencephaly and bilateral anophthalmia in one out of 269 specimens of the 3000 mg/kg bw/d dose group. This one instance of malformation is considered to be of a spontaneous origin and not related to treatment with the test item. Malformations concerning the facial differentiation of the skull are found spontaneously at a relatively high incidence in the breed of rats used in the present study.
By applying the slicing technique two foetuses of the high-dose group showed anasarca, i.e. slight oedema-like changes of siabcutaneous tissue, an anomaly occasionally observed in controls, too. The one of those two foetuses affected is identical to the aforementioned malformed one.
Skeletal assessment revealed no clearcut deviations between experimental groups and controls with the exception of a slightly increased number of not yet ossified phalangeal nuclei of hind-limb in both the intermediate and high dose group as well as not yet ossified calcanei in the high-dose group. Findings of this kind are considered to be entirely non-specific and may reflect mild toxicity of the compound in the dams.

Key result

Dose descriptor:

NOAEL

Effect level:

3 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Key result

Abnormalities:

not specified

Key result

Developmental effects observed:

not specified

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

3 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Comparable to guideline requirements

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In the key study, the test item was administered orally to pregnant rats from day 6 until day 15 of gestation, inclusive. The doses were 300, 1000 and 3000 mg/kg of body weight. Concerning the progeny, the foetuses of the low-dose group were found to be entirely unaffected by the administration of the compound to the dams. At the intermediate and high-dose level a slight delay of the physiological growth of the foetuses was indicated by an increase in the number of not yet ossified phalangeal nuclei of the hind-limb as well as calcanei (high-dose group only). Findings of this kind are considered to be entirely non-specific and may reflect mild toxicity of the compound in the dams. No teratogenic effects were observed. The NOAEL was 3000 mg/kg bw/d.

In a supporting study, the test item was administered orally to pregnant mice from day 6 until day 15 of gestation, inclusive. The doses were 300, 1000 and 3000 mg/kg of body weight. Except for a slightly reduced feed consumption during the late period of treatment and the post-treatment period of the experiment, the dams of the three dose groups did not show any signs of intolerability of the compound. The progeny was not adversely affected by the test item. The reproduction data were comparable for all experimental groups and vehicle control. No teratogenic effects were observed. The NOAEL was 3000 mg/kg bw/d.

Justification for classification or non-classification

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

The available experimental test data are also reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. As a result the substance is not considered to be classified under Regulation (EC) No 1272/2008, as amended for the eighth time in Regulation (EU) No 2016/218 for toxicity to reproduction.