Bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 June 2015 to February 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

see results

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine

EC Number:

239-816-9

EC Name:

Bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine

Cas Number:

15721-78-5

Molecular formula:

C28H43N

IUPAC Name:

4-(2,4,4-trimethylpentan-2-yl)-N-[4-(2,4,4-trimethylpentan-2-yl)phenyl]aniline

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Batch No.: not specified
- Purity: not specified

Specific details on test material used for the study:

- CAS RN: CAS RN 15721-78-5
- Physical State/Appearance: Off white powder
- Purity: 93.2%
- Batch Number: HY14KSV07
- Date Received: 11 October 2015

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

- Ninety-six time-mated female Sprague-Dawley Crl:CD (SD) IGS BR strain rats were used
- Animals were delivered in one batch prior to Day 3 of gestation
- The day that positive evidence of mating was observed was designated Day 0 of gestation
- At the start of treatment, the females weighed 205 to 280g
- Housed individually
- Solid-floor polypropylene cages with stainless steel mesh lids furnished with softwood flakes color coded cage cards were prepared with details of test item, study number, dose level, sex, number of animals, route of administration and Study Director responsible for the study
- Free access to food and water
- Pelleted diet rodent feed (Rodent 2018C)
- Mains drinking water was supplied from polycarbonate bottles attached to the cage
- Environmental enrichment - wooden chew blocks and cardboard fun tunnels
- The animals were housed in a single air-conditioned room within the laboratory
- Air exchange was at least fifteen air changes per hour
- 12 hours continuous light, 12 hours darkness
- Target ranges for temperature and relative humidity were 22 ± 3 ºC and 50 ± 20% respectively. Short term deviations from these targets were considered not to have affected the purpose or integrity of the study; see deviations from Study Plan.
- Animals were randomly allocated to treatment groups based on stratified body weight
- Animals were identified by an ear punching system

Schedule
Experimental Starting Date: 08 June 2015
Experimental Completion Date: 16 July 2015

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on exposure:

The test item was prepared at the appropriate concentrations as a suspension in Arachis oil BP.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability and homogeneity of the test item formulations were determined as part of another study and showed the formulations to be stable for up to twenty five days when stored refrigerated (approximately 4°C) in the dark. Formulations were prepared twice during the study, divided into daily aliquots and stored as above prior to use. Samples were taken of each test item formulation and were analyzed for concentration of bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine (CAS RN 15721-78-5 The formulations investigated during the study were found to comprise test item in the range of the required content limit of ±10% with reference to the nominal content.

Duration of treatment / exposure:

The test item was administered by gavage to three groups each of twenty-four time-mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between Days 3 and 19 of gestation.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

300 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

The test item was administered by gavage to three groups each of twenty-four time-mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between Days 3 and 19 of gestation inclusive at dose levels 100, 300, and 1000 mg/kg bw/day.

Control animals:

yes

yes, concurrent vehicle

Examinations

Maternal examinations:

The test item was administered by gavage to three groups each of twenty-four time-mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between Days 3 and 19 of gestation. Clinical signs, body weight change, food and water consumptions were monitored during the study.

Ovaries and uterine content:

All surviving females were terminated on Day 20 of gestation and subjected to gross necropsy, including examination of the uterine contents. The number of corpora lutea, number, position and type of implantation, placental weights, fetal weight, sex and external and internal macroscopic appearance were recorded.

Fetal examinations:

Half of each litter was examined for detailed skeletal development and the remaining half was subjected to detailed visceral examination.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No clinical signs for any of the animals considered to be related to treatment with the test item.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

There were no treatment-related deaths during the study.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

There was no effect of treatment at any dose level on body weight development.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

no effects observed

Description (incidence and severity):

Dietary intake across all groups of females receiving the test item remained similar to controls throughout the treatment period.

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

no effects observed

Description (incidence and severity):

Visual inspection of water bottles did not indicate any intergroup differences in water consumption when compared with controls.

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no treatment-related macroscopic findings for any of the females sent to the scheduled necropsy on Day 20 of gestation.

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Maternal developmental toxicity

Number of abortions:

not specified

Pre- and post-implantation loss:

not specified

Total litter losses by resorption:

not specified

Early or late resorptions:

not specified

Dead fetuses:

not specified

Changes in pregnancy duration:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not specified

Changes in number of pregnant:

not specified

Other effects:

no effects observed

Description (incidence and severity):

No treatment-related effects were detected in the uterine parameters examined, in fetal viability or in fetal growth and development. No treatment-related effects were detected on external development or in the type and incidence of skeletal or visceral findings.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

behaviour (functional findings)

body weight and weight gain

changes in number of pregnant

changes in pregnancy duration

clinical biochemistry

clinical signs

dead fetuses

early or late resorptions

effects on pregnancy duration

food efficiency

gross pathology

maternal abnormalities

mortality

necropsy findings

number of abortions

organ weights and organ / body weight ratios

pre and post implantation loss

total litter losses by resorption

water consumption and compound intake

Maternal abnormalities

Key result

Abnormalities:

effects observed, non-treatment-related

Results (fetuses)

Fetal body weight changes:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not specified

Reduction in number of live offspring:

not specified

Changes in sex ratio:

not specified

Changes in litter size and weights:

not specified

Changes in postnatal survival:

not specified

External malformations:

no effects observed

Description (incidence and severity):

No treatment-related effects were detected on external development.

Skeletal malformations:

no effects observed

Description (incidence and severity):

No treatment-related effects were detected iin the type and incidence of skeletal findings.

Visceral malformations:

no effects observed

Description (incidence and severity):

No treatment-related effects were detected regarding visceral findings.

Other effects:

not specified

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

not specified

Basis for effect level:

reduction in number of live offspring

changes in sex ratio

fetal/pup body weight changes

changes in litter size and weights

changes in postnatal survival

external malformations

skeletal malformations

visceral malformations

Fetal abnormalities

Key result

Abnormalities:

effects observed, non-treatment-related

Overall developmental toxicity

Key result

Developmental effects observed:

no

Any other information on results incl. tables

Deviation No. 1

According to the Study Plan, target ranges for relative humidity were to be between 30 to 70%.  Instances of higher relative humidity were noted for this study on 20 June 2015.  During these episodes, the relative humidity ranged between 72.58 to 83.20% RH.  Although these instances of higher relative humidity were less than ideal, they were seen on one day only and were of short duration with each lasting up to a maximum of two hours.  The clinical condition of the animals was unaffected and this deviation from the Study Plan was therefore considered not to have any impact on the scientific integrity of the study or the results obtained.

See attachment for Tables.

Applicant's summary and conclusion

Conclusions:

Under the conditions of the study, the oral administration of bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine (CAS RN 15721-78-5) to pregnant rats by oral gavage during gestation at dose levels of 100, 300 and 1000 mg/kg bw/day was well tolerated. The ‘No Observed Effect Level’ (NOEL) for maternal toxicity was considered to be 1000 mg/kg bw/day. No treatment-related changes were detected in the offspring parameters measured. The ‘No Observed Effect Level’ (NOEL) for developmental toxicity, was, therefore, considered to be 1000 mg/kg bw/day.

Executive summary:

The study was designed to investigate the effects of bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine (CAS RN 15721-78-5):on embryonic and fetal development following repeated administration by gavage to the pregnant female during gestation including the period of organogenesis. The study was performed to OECD 414 Test Guidelines under GLP conditions.

The test item was administered by gavage to three groups each of twenty-four time-mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between Days 3 and 19 of gestation inclusive at dose levels 100, 300, and 1000 mg/kg bw/day. A group of twenty-four time-mated females was treated with the vehicle only (Arachis oil BP) to serve as a control. Clinical signs, body weight change, food and water consumptions were monitored during the study. 

All surviving females were terminated on Day 20 of gestation and subjected to gross necropsy, including examination of the uterine contents. The number of corpora lutea, number, position and type of implantation, placental weights, fetal weight, sex and external and internal macroscopic appearance were recorded. Half of each litter was examined for detailed skeletal development and the remaining half was subjected to detailed visceral examination.

There were no treatment-related deaths during the study. No clinical signs for any of the animals considered to be related to treatment with the test item. There was no effect of treatment at any dose level on body weight development. Dietary intake across all groups of females receiving the test item remained similar to controls throughout the treatment period. Visual inspection of water bottles did not indicate any intergroup differences in water consumption when compared with controls. There were no treatment-related macroscopic findings for any of the females sent to the scheduled necropsy on Day 20 of gestation. No treatment-related effects were detected in the uterine parameters examined, in fetal viability or in fetal growth and development. No treatment-related effects were detected on external development or in the type and incidence of skeletal or visceral findings.

The oral administration of bis(4-(1,1,3,3-tetramethylbutyl)phenyl)amine (CAS RN 15721-78-5) to pregnant rats by oral gavage during gestation at dose levels of 100, 300 and 1000 mg/kg bw/day was well tolerated. The ‘No Observed Effect Level’ (NOEL) for maternal toxicity was considered to be 1000 mg/kg bw/day.

No treatment-related changes were detected in the offspring parameters measured. The ‘No Observed Effect Level’ (NOEL) for developmental toxicity was, therefore, considered to be 1000 mg/kg bw/day.