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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:
08 February 2017 to 10 November 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Details on test material:
CAS number: Not yet known
EC Number: Not yet known
Specific details on test material used for the study:
Physical Description: Dark brown, clear liquid
Purity: 91%

Test animals

Species:
rat
Strain:
other: Crl:CD(SD)
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
The test substance formulations were prepared approximately weekly as single formulations for each dosage level, divided into aliquots in corn oil for daily dispensation, and stored refrigerated (2°C to 8°C), protected from light. The test substance formulations were stirred continuously throughout the preparation, sampling, and dose administration procedures.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Test material formulations prepared at concentrations of 20, 60, and 200 mg/mL were analyzed by a validated high performance liquid chromatography method using ultraviolet absorbance detection at a wavelength of 260 nm. The analytical results met the applicable protocol-specified acceptance criteria. No test substance was detected in the analyzed vehicle administered to the control group.
Duration of treatment / exposure:
Males were dosed throughout the mating period through 1 day prior to euthanasia for a total of 28 doses.
Females received 14 daily doses prior to pairing and were dosed through Lactation Day 13 for a total of 49–53 doses.
Frequency of treatment:
Once daily
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
300 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Details on study design:
The dose selection was based upon a range-finding study (please see RSS section 7.5.1 Supporting study, Charles River, 2017 (range-finding)).

Examinations

Observations and examinations performed and frequency:
Detailed observations were performed to establish and confirm a pattern of signs in association with dosing according to the following schedule:

F0 Males
Weeks 1-3: Twice daily
Last week of dosing (Study Day 26): 5 males/group only

F0 Females
Week 1 - Twice daily
Last week of dosing (Lactation Day 13): 5 females/group only
Lactation Day 14

Detailed observations were recorded at the following times in relation to dose administration: Approximately 1.5 hours after dosing
Sacrifice and pathology:
All F0 adults were euthanized by carbon dioxide inhalation.
Males were euthanized following completion of the mating period.
Females that delivered were euthanized on Lactation Day 14; one vehicle control female that failed to deliver was euthanized on Postcohabitation Day 25.
All adult animals were subject to a detailed necropsy.
Statistics:
Analyses were conducted using two-tailed tests (except as noted otherwise) for minimum significance levels of 1% and 5%, comparing each test substance-treated group to the control group. Body weights, body weight changes, and absolute and relative organ weights were subjected to a parametric one-way ANOVA2 to determine intergroup differences. If the ANOVA revealed significant (p < 0.05) intergroup variance, Dunnett's test was used to compare the test substance-treated groups to the control group.

Results and discussion

Results of examinations

Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
Clinical observations noted in the test substance-treated groups, including red and yellow material on various body surfaces and hair loss on the forelimbs, were noted infrequently, similarly in the vehicle control group, and/or in a manner that was not dose-related.
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:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
effects observed, non-treatment-related
Description (incidence and severity):
The statistically significant differencse from the vehicle control group were an increased mean potassium level and decreased mean sodium level in the 100 mg/kg/day group F0 males and a lower mean bile acid level in the 300 mg/kg/day group F0 males. There was no dose-response relationship, no similar occurrence in the opposite sex, and/or the changes were of minimal magnitude. These differences from the vehicle control group were considered to be the result of normal biological variation and were not considered to be of toxicological significance.
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
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:
not examined
Other effects:
no effects observed
Description (incidence and severity):
There were no test substance-related effects on thyroid hormone values in the F0 males at any dosage level. Differences from the vehicle control group were considered to be the result of normal biological variation and were not considered to be of toxicological significance.

Effect levels

Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
body weight and weight gain
food efficiency
haematology
clinical biochemistry
organ weights and organ / body weight ratios
gross pathology
histopathology: non-neoplastic

Target system / organ toxicity

Key result
Critical effects observed:
no

Applicant's summary and conclusion

Conclusions:
The No-observed-adverse-effect-level (NOAEL) of the test item for systemic toxicity effects was considered to be 1000 mg/kg/day when administered orally by gavage to Crl:CD(SD) rats.
Executive summary:

The potential toxic effects of the test substance at dosage levels of 100, 300 and 1000 mg/kg bw/day were investigated in an OECD 422 study, performed under GLP conditions. The test substance or vehicle control (corn oil) was administered to rats via gavage once daily to 4 groups of Crl:CD(SD) rats, each group consisting of 10 males and 10 females.

 

All F0 animals survived to the scheduled necropsies. No test substance-related clinical observations were noted for the 100, 300, and 1000 mg/kg/day group F0 males and females during the weekly detailed physical examinations, at the daily examinations, or approximately 1.5 hours following dose administration. No test substance-related effects were noted on F0 male and female body weights, body weight gains, or food consumption at any dosage level throughout the study. There were no test substance-related effects on F0 organ weights, hematology and serum chemistry parameters, and serum T4 levels (males only) in the 100, 300, and 1000 mg/kg/day groups. No test substance-related gross necropsy observations or microscopic findings were noted for F0 males and females at any dosage level.

 

Under the conditions of this screening study, 1000 mg/kg/day was considered to be the no-observed-adverse-effect level (NOAEL) for systemic toxicity when administered orally by gavage to Crl:CD(SD) rats.