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Toxicological information

Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
14 days
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well documented study according to OECD 401 and Japanese "Chemical Substance GLP". Could easily be a K1 if study appendices located, QA and GLP statement provided, and C of A.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
yes
Remarks:
"Chemical Substances GLP" Japan
Test type:
acute toxic class method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (abbreviated BPTC hereafter) was used as the test substance. The test substance is also called Perhexa 3M and the English name is 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, which is a colorless, clear liquid, CAS No. 6731-36-8, with molecular weight 302.46, molecular formula C17H34O4, melting point (solidifying point) below -40°C and vapor pressure 4.3 mm Hg/83°C.

The BPTC (Lot No. ___, 97.9 wt% purity) used in the present study was supplied by ___. The test substance received was stored in a test sample-storage room until the study.

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
male/female
Details on test animals and environmental conditions:
Animals used and raising method
4-week-old female and male Sprague-Dawley [Crj:CD(SD)IGS, SPF] rats were purchased from Japan Charles River K.K. Tsukuba Breeding Center and the animals were preconditioned for 8 days for acclimatization to the raising condition as well as for quarantine. No abnormalities were observed in general condition in the animals during the preconditioning period. 15 males and 5 females were used for the study. The males were divided randomly into 3 groups with 5 per group based on the body weights at the end of quarantine, and a group of 5 females was selected from the group of animals in the most recent shipment. The age was 5 weeks for both the females and males at the start of administration (note).
___________________________________________________________
(Note) Animals received: January 27, 1999
Number of animals received: 17 males and 6 females
Body weights when received: 79.8-90.1 g for males and 79.3-84.0 g for females
Date of administration: February 4, 1999
Body weights at the time of administration: 123.8-144.3 g for males and 109.6-121.4 g for females

Each animal was housed in a metal mesh cage (WDH; 220 mm x 270 mm x 190 mm) in a breeding room at standard temperature of 24 ± 1°C, standard humidity of 50-65%, 15 ventilations/h and 12 h illumination (illumination 7:00 a.m. to 7:00 p.m.), and solid feed (CE 2, product of Japan Clea K.K.) and water (city water from Hatano City Water Department) were given freely. In this regard, the measured temperature and humidity were 24.0-24.5°C and 48.5 65.5%, respectively. The humidity deviated slightly from the standard humidity but the deviation lasted less than 1 h and the rest was within thestandard range. Also, the diet and water given contained no foreign matter that could cause disruption of the study.

Oil-based felt-tip pens were used to mark sequence numbers on the tails of the animals for identification. Also, an animal card labeled with the study protocol number, dose, sex and animal number was attached to each cage to aid identification of each individual animal.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
Preparation of administration samples
The administration samples were prepared by weighing the test substance for each dose and dissolving it in corn oil (product name: corn oil, Lot No. V8P7069, product of Nakarai K.K.) to a given concentration. The samples were stored in a cold area away from light until administration, which was 3 days after preparation.

Samples of 2 and 20% w/v of the test substance were validated as being stable for 12 days in a cold area away from light (Appendix A-not part of translation) by means of a 28-day multiple oral toxicity study of this test substance in rats that was previously conducted at Hatano Research Institute (study protocol No.: C-98-017). Also, the content of the test substance in each sample for administration was tested and verified to be within specifications (Appendix B-not part of translation). In this case, a uniformity test was not performed because the administration samples were all in liquid form.The concentration of the test substance in the prepared samples was determined by gas chromatography (Appendix C-not part of translation).

Establishment of doses and administration method
The doses for the present study were established based on the result of a literature survey (RTECS No.: SD8600000), as well as on the results from a preliminary study (study protocol No.: C-98-016) of the 28-day multiple oral toxicity of the present substance conducted for dose setting. Specifically,the LD50 found from the literature survey for the present test substance was 12,918 mg/kg [1], and 2 doses, namely, 1000 and 2000 mg/kg, were established for 1 sex (male) because a mild inhibitory effect on the body weight was observed in the females at 1000 mg/kg dose in the initial stage of the preliminary study, while a vehicle control group was established to which corn oil was administered at the same volume as the test substance solution. Also, 1 dose at 2000 mg/kg was established for the females because no gender difference was observed in the preliminary study.

The volume administered was 10 mL per 1 kg body weight and the quantity administered was calculated based on the body weight measured immediately prior to administration, which was after the animal had been fasted for about 18 h. One single forcible oral administration was conductedusing a gastric tube for rats. Administration was conducted at 9:43-9:55 a.m. and food was given about 3 h after administration.

Doses:
1000 and 2000 mg/kg, were established for 1 sex (male)
Also, 1 dose at 2000 mg/kg was established for the females.
No. of animals per sex per dose:
5
Control animals:
yes

Results and discussion

Preliminary study:
The doses for the present study were established based on the result of a literature survey (RTECS No.: SD8600000), as well as on the results from a preliminary study (study protocol No.: C-98-016) of the 28-day multiple oral toxicity of the present substance conducted for dose setting. Specifically, the LD50 found from the literature survey for the present test substance was 12,918 mg/kg [1], and 2 doses, namely, 1000 and 2000 mg/kg, were established for 1 sex (male) because a mild inhibitory effect on the body weight was observed in the females at 1000 mg/kg dose in the initial stage of the preliminary study, while a vehicle control group was established to which corn oil was administered at the same volume as the test substance solution. Also, 1 dose at 2000 mg/kg was established for the females because no gender difference was observed in the preliminary study. The volume administered was 10 mL per 1 kg body weight and the quantity administered was calculated based on the body weight measured immediately prior to administration, which was after the animal had been fasted for about 18 h. One single forcible oral administration was conducted using a gastric tube for rats. Administration was conducted at 9:43-9:55 a.m. and food was given about 3 h after administration.
Effect levels
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Mortality:
None
Clinical signs:
For males, diarrhea or loose stools were observed on the day of administration in 2 cases in the vehicle control group, 4 cases in the 1000 mg/kg group and 3 cases in the 2000 mg/kg group, and perianal soiling was observed on the day of administration or observation day 2 in 3 cases in the 2000 mg/kg group.

Diarrhea or loose stools were also observed on the day of administration in 3 females in the 2000 mg/kg group. No other abnormalities were observed.
Body weight:

Normal body weight increases were observed in the females and males after administration.
Gross pathology:
No abnormalities were observed in the organs/tissues in any female or male during the necropsy performed on observation day 15.

Applicant's summary and conclusion

Interpretation of results:
not classified
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The LD50 for BPTC under the conditions of this study is estimated to be higher than 2000 mg/kg in female and male rats.
Executive summary:

Acute single oral toxicity of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (abbreviated as BPTC hereafter) was investigated in Sprague-Dawley [Crj:CD(SD)IGS, SPF] rats. Single oral doses of BPTC were administered to 5-week-old male rats in groups of 5 at 1000 and 2000 mg/kg, respectively, and to 5-week-old female rats in a group of 5 at 2000 mg/kg, and the rats were observed from observation day 1 (the day of administration) for 14 days, followed by necropsy on observation day 15. In addition, 10 mL/kg corn oil was administered to 5 males in a vehicle control group and they were observed in the same manner. Diarrhea or loose stools were observed in all administration groups, with slightly higher incidence in the BPTC administration groups. No abnormal changes were observed in any case in body weight changes or in observations in necropsy performed on observation day 15. From these findings, the LD50for BPTC under the conditions of this study is estimated to be higher than 2000 mg/kg in female and male rats.