Registration Dossier

Administrative data

Endpoint:
short-term repeated dose toxicity: other route
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed journal

Data source

Reference
Reference Type:
publication
Title:
Repeated dose toxicity study of the test chemical
Author:
Kanga et al
Year:
2005
Bibliographic source:
Toxicology

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: refer below principle
Principles of method if other than guideline:
Repeated dose toxicity study was performed to determine the mutagenic nature of the test chemical
GLP compliance:
not specified
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
tert-butyl-4-methoxyphenol
EC Number:
246-563-8
EC Name:
tert-butyl-4-methoxyphenol
Cas Number:
25013-16-5
Molecular formula:
C11H16O2
IUPAC Name:
(1,1-Dimethylethyl)-4-methoxyphenol
Details on test material:
- Name of test material: N Butylated hydroxyanisole
- Molecular formula : C11H16O2
- Molecular weight: 181.2533 g/mol
- Substance type: Organic

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: National Veterinary Research and Quarantine Service (Anyang, Korea).
- Age at study initiation: 20-days-old immature female
Housing: All animals were cared according to the guidelines for good animal laboratory practices prepared by National Veterinary Research and Quarantine Services.
- Diet (e.g. ad libitum): Commercial diet, ad libitum
- Water (e.g. ad libitum): Tap water, ad libitum
Temperature (°C): 24±2 ◦C
- Humidity (%): 50±20%
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): 12-h
light/dark cycle

Administration / exposure

Route of administration:
subcutaneous
Vehicle:
corn oil
Details on exposure:
BHA was dissolved in corn oil and diluted to dosages of 50, 100, 250 and 500 mg/kg
Area of exposure: dorsal surface, caudal to the nape of neck

Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
3 days
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:
50, 100, 250 and 500 mg/kg
No. of animals per sex per dose:
Total : 76
0 mg/kg/body weight/day: 11 female
50 mg/kg/body weight/day: 11 female
100 0 mg/kg/body weight/day: 11 female
250 mg/kg/body weight/day: 11 female
500 mg/kg/body weight/day: 11 female
2 µg/kg + 50 mg/kg ( E2 +BHA): 7 female
2 µg/kg + 500 mg/kg ( E2 +BHA): 7 female
2 µg/kg (E2): 7 female
Control animals:
yes, concurrent no treatment
Details on study design:
Dose selection rationale: Doses were referenced from NOEL (No observed effect level, 250 mg/kg) of BHA (WHO, 1989; Vorhees et al., 1981). Animals were assigned on the basis of age.

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily
BODY WEIGHT: Yes
- Time schedule for examinations: Daily
FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: Daily
CLINICAL CHEMISTRY: Yes
All 76 rat were examined
Statistics:
Body weight gain, organ weights, consumption of feed and water, uterine epithelial cell height and hormone contents were analyzed by one-way analysis of variance with post hoc comparison between the vehicle control or positive control group and each treatment group, followed by Duncan’s multiple comparison using Statistica program (Version 5.5). A p value < 0.05 was taken as a statistically significant difference between two groups.

Results and discussion

Results of examinations

Clinical signs:
not specified
Mortality:
not specified
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
When treated with 250 and 500 mg/kg/day significant decreased in body weight gain were observed as compare to control. 17 β-estradiol with BHA 500 mg/kg/day: Significant decreased were observed as compare to control in female rat.
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
No change was observed in Estradiol level of treated rat
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Absolute and Relative Uterine weight was significantly decreased in 50, 100,250 and 500 mg/kg/day dose group. 17 β-estradiol with BHA 500 mg/kg/day: Significant decreased were observed in relative liver weight as compare to control
Gross pathological findings:
not specified
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
No effect was observed in Uterine epithelial cell height of trested female rat as compare to control Also,BHA 50 or 500 mg/kg/day did not affect on 17β-estradiol induced increase of uterine epithelial cell height
Histopathological findings: neoplastic:
not specified
Other effects:
not specified

Effect levels

Dose descriptor:
LOAEL
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: Effect on body weight gain and organ weight

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Low observed adverse effect level (LOAEL) was considered to be 50 mg/kg/body weight/day when female rat were sub-cutaneously exposed to the test chemical.
Executive summary:

In a repeated dose subcutaneous toxicity study, female Crj:CD (SD) rats were exposed to the test chemical by subcutaneous injection into dorsal surface, caudal to the nape of neck in the concentration of 0, 50, 100, 250 and 500 mg/kg/body weight/day. Toxic changes were observed as decrease in body weight gain of 250 and 500 mg/kg/day treated female rat. Changes were also observd in uterine weight of female rat at 50 mg/kg/day. Therefore, Low observed adverse effect level (LOAEL) is considered to be 50 mg/kg/body weight/day when female rats are exposed to the test chemical by subcutaneous injection for 3 days.