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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not specified
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
other: SIDS Dossier data
Title:
Unnamed
Year:
2006
Report date:
2006

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
not specified
GLP compliance:
yes
Limit test:
yes

Test material

Constituent 1
Reference substance name:
68442-68-2
Cas Number:
68442-68-2
IUPAC Name:
68442-68-2
Test material form:
liquid: viscous
Details on test material:
CAS No: 68442-68-2
EINECS No: 270-485-3
EINECS Name: Benzenamine, N-phenyl-, styrenated
CAS Name: Benzenamine, N-phenyl-, styrenated
Substance type: organic
Physical status: liquid
Purity: > 98 % w/w
Result: Molecular weight: 320

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
Species: rat
Sex: male/female
Strain: Sprague-Dawley Crl:CD® (SD) IGS BR

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
Not specified
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
Males: 43 days; Females: up to 54 days
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 50, 250 and 600 mg/kg/day
Basis:
actual ingested
No. of animals per sex per dose:
Ten males and ten females pr dosing group.
Control animals:
yes, concurrent vehicle
Details on study design:
Not specified
Positive control:
No data

Examinations

Observations and examinations performed and frequency:
Clinical signs, behavioural assessments, bodyweight development, food and water consumption were monitored during the study. Haematology and blood chemistry were evaluated prior to mating on five selected males and females from each dose group.
Sacrifice and pathology:
Males were terminated on Day 43, followed by the termination of all surviving females and offspring on Day 5 post partum. All animals were subjected to a gross necropsy examination and histopathological evaluation of selected tissues was performed.
Other examinations:
Pairing of animals within each dose group was undertaken on a one male: one female basis on Day 15 of the study, to produce litters. Extensive functional observations were performed on five selected parental males from each dose group after the completion of the mating phase, and for five selected parental females from each dose group on Day 4 post partum.

Results and discussion

Results of examinations

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):
no effects observed
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
Elevated alkaline phosphatase levels, reduced cholesterol levels.
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Elevated liver and adrenal weights,
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
liver and thyroid gland
Histopathological findings: neoplastic:
no effects observed
Details on results:
Mortality: No treatment-related deaths were detected.

Clinical Observations: No clinically observable signs of toxicity were detected.

Behavioural Assessments: No treatment-related effects were detected.

Functional Performance Tests: No treatment-related effects were detected.

Sensory reactivity Assessments: No treatment-related effects were detected.

Bodyweights: No adverse effect on bodyweight was observed for males throughout the treatment period, or for females during the maturation, gestation or lactation phases of the study.

Food Consumption: No adverse effect on dietary intake was detected for males throughout the treatment period, or for females during the maturation, gestation or lactation phases of the study.

Water Consumption: No overt intergroup differences were detected. Haematology: No treatment-related changes were detected prior to mating.

Blood Chemistry: Elevated alkaline phosphatase levels were detected for males treated with 600 mg/kg/day. Males treated with 600 and 250 mg/kg/day also showed reduced cholesterol levels. No such effects were detected for females treated with 600 or 250 mg/kg/day or for animals of either sex treated with 50 mg/kg/day.

Necropsy of Adults: No treatment-related macroscopic abnormalities were detected for the interim death female or for the remaining animals at terminal kill.

Organ Weights: Elevated liver and adrenal weights, both absolute and relative to terminal bodyweights, were detected for animals of either sex treated with 600 mg/kg/day.

Histopathology: Histopathological examination of adult tissue revealed the following treatment-related changes:
Liver: Centrilobular hepatocyte enlargement was observed for animals of either sex treated with 600 and 250 mg/g/day, with the effect extending into the female 50 mg/kg/day dose group.
Thyroid glands: Follicular cell hypertrophy was observed for males treated with 600 and probably also at 250 mg/kg/day. No such effects were detected for females at these dose levels, or for animals of either sex treated with 50 mg/kg/day.

These effects however, were considered entirely adaptive in nature, therefore the ‘No Observed Adverse Effect Level’ (NOAEL) was considered to be 600 mg/kg/day.

Effect levels

Dose descriptor:
NOAEL
Effect level:
600 other: mg/kg/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: overall effects

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
No Observed Adverse Effect Level (NOAEL) was considered to be 600 mg/kg/day.
Executive summary:

Study conducted to OECD test guidance in compliance with GLP and data included for OECD SIDS dossier. The oral administration of CAS No 68442-68-2 to rats by gavage, at dose levels of 600, 250 and 50 mg/kg/day, resulted in treatment-related effects at all dose levels. These effects however, were considered entirely adaptive in nature, therefore the ‘No Observed Adverse Effect Level’ (NOAEL) was considered to be 600 mg/kg/day. Read across to supporting substance, CAS No. 68442 -68 -2, by structural analogue.

This substance has been supported under Environmental Protection Agency’s (EPA’s) High Production Volume (HPV) Challenge Program. The American Chemical Councils RAPA Panel, has derived a “Substituted Diphenylamines” category of chemicals for this substance, please refer to EPA reference 201-14700A located at

 

http://www.epa.gov/hpv/pubs/summaries/subdipha/c13378rt.pdf

 

Relying on several factors specified in EPA’s guidance document on “Development of Chemical Categories in the HPV Challenge Program,” in which use of chemical categories is encouraged, the following closely related chemicals constitute a chemical category:

 

Structural Similarity. A key factor supporting the classification of these chemicals as a category is their structural similarity (see Figure 1). All share a common starting material; Diphenylamine (Benzenamine, N-phenyl-, CAS# 122-39-4), a common synthetic pathway, and all compounds in this category are diamines with various substitutions.

 

Similarity of Physicochemical Properties. The similarity of the physicochemical properties of these materials parallels their structural similarity. All are off-white to light brown solids or viscous liquids intended for use as antioxidants in finished rubber articles or as antidegradant additives that extend the useful life of heavy-duty industrial functional fluids used in high-speed, high-temperature and/or high-load applications. As a class, these amine-based antidegradant compounds are less migratory (more polymer-bound) and less staining than the Substituted p-Phenylenediamine antidegradants. The use of these materials requires that they be stable under high temperatures. Their low volatility is due to their low vapor pressure, highly viscous or solid form. The existing information for these materials indicates that they have low water solubility and high flash points.

 

Fate and Transport Characteristics. Members of this category have been shown to be not readily biodegradable, so additional testing is not needed. The lack of water solubility of the members of this category makes hydrolysis testing unnecessary. These materials have been shown not to partition to water or air if released into the environment due to their low water solubility and low vapor pressure.

 

Toxicological Similarity. Review of existing published and unpublished test data for Substituted Diphenylamines shows the aquatic and mammalian toxicity among the materials within this category are similar.

 

Mammalian Toxicology - Acute. Data on acute mammalian toxicity were reviewed, and the findings indicate a low concern for acute toxicity for all materials. Data are available for most members of the category indicating that the category has been well tested for acute mammalian effects. Therefore, for the purposes of the HPV Program, no

additional acute mammalian toxicity testing is proposed.

 

Mammalian Toxicology - Mutagenicity. Data from bacterial reverse mutation assays, in vitro and in vivo chromosome aberration studies, as well as additional supporting in vitro and in vivo genetic toxicity studies were reviewed, and the findings indicate a low concern for mutagenicity either for aryl or alkyl substituted materials. Similarly, the data for a mixed aryl/alkyl substituted molecule also indicates a lack of mutagenicity. Data are available for several members of the category or close structural analogs, and these data can be bridged to the other members of the category. Therefore, for the purposes of the HPV Program, the category has been adequately tested for mutagenicity, and no additional mutagenicity testing is proposed.

 

Mammalian Toxicology – Repeated Dose Toxicity. Data from repeated-dose toxicity studies were reviewed. Sufficient data are not available to adequately represent the Substituted Diphenylamines for the purposes of the HPV Program, and additional testing is proposed on the smallest aryl- and akyl-substituted materials.

 

Mammalian Toxicology - Reproductive and Developmental Toxicity. Data from reproductive and developmental toxicity studies were reviewed. Sufficient data are not available to adequately represent the Substituted Diphenylamines for the purposes of the HPV Program, and additional testing is proposed, and additional testing is proposed. It is proposed to test the smallest aryl- and akyl-substituted materials.

 

Conclusion. Based upon the data reviewed in “Substituted Diphenylamines” category of chemicals, the physicochemical and toxicological properties of the Substituted Diphenylamine category members are similar and follow a regular pattern as a result of that structural similarity. Therefore, the definition of a chemical category has been met, and read across is considered appropriate for the category of chemical.