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

Developmental toxicity / teratogenicity

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1975

Report date:

1975

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

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

EC Number:

224-166-0

EC Name:

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

Cas Number:

4221-80-1

Molecular formula:

C29H42O3

IUPAC Name:

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

Test animals

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

Administration / exposure

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

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

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

Examinations

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.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

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.

Effect levels (maternal animals)

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

Maternal abnormalities

Key result

Abnormalities:

no effects observed

Results (fetuses)

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.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

3 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Key result

Abnormalities:

not specified

Overall developmental toxicity

Key result

Developmental effects observed:

not specified