1,1,4,4-tetramethylbutane-1,4-diyl bis(2-ethylperoxyhexanoate)
The oral LD50 is > 2000 mg/kg bw. No mortalities occurred and no signs of systemic toxicity were observed during the 14-day observation period. There are no key studies available for the inhalation or the dermal route.
14 October 1992 - 6 November 1992
other: The study is performed according to OECD guidelines and GLP.
- Source: Charles River (U.K.) Limited, Margate, Kent, England
- Age at study initiation:5 weeks
- Weight at study initiation: males from 116 - 138 g and for females from 116 - 131 g.
- Fasting period before study: removal of food for approximately 18 hours before administration of the test material.
- Housing: The animals were housed in stainless steel grid cages (Stephen Clark Fabrications Limited, Alva, Clackmannanshire, Scotland).
- Diet (e.g. ad libitum):ad libitum, commercially-available complete pelleted rodent diet (RM-1 S.Q.C., from Special Diets Services Limited, Witham, Essex, England)
- Acclimation period: at least 5 days
- Photoperiod (hrs dark / hrs light):12/12
IN-LIFE DATES: 14 October 1992 - 6 November 1992
maize oil
- Concentration in vehicle: 200mg/ml
- Amount of vehicle (if gavage): 10ml/kg
DOSAGE PREPARATION (if unusual): The dosage was calculated and expressed gravimetrically in terms of the material as received. A fresh formulation of the test material was prepared shortly before administration and any surplus remaining after dosing was destroyed on the same day
- Frequency of observations and weighing: Three separate inspections were made during the first hour after dosing and two further inspections during the remainder of Day 1. From Day 2 onwards the animals were inspected twice daily (morning and afternoon). The type t time of onset and duration of reactions to treatment were recorded. The bodyweight of each animal was recorded on the day before dosing and on Days It 8 and 15. The test was terminated on the morning of Day 15
other: no mortalities
There was no death.
other: There was no sign of reaction to treatment.
Necropsy, on Day 15, revealed no significant macroscopic lesion.
LD50 > 2000 mg/kg bw.
The acute oral toxicity was investigated in a group of five male and five female CD rats at a dosage of 2000 mg/kg. The animals were starved overnight prior to dosing and the test material was administered at a constant volume-dosage of 10 ml/kg in maize oil. Mortality and signs of reaction to treatment were recorded during a subsequent 14-day observation period. The animals were killed on the following day and subjected to necropsy. There was no death and no sign of reaction to treatment. The animals achieved expected bodyweight gains and necropsy
revealed no significant macroscopic lesion. Under the conditions of this study, the acute oral median lethal dosage (LD50) of the test material was greater than 2000 mg/kg.
A K1 study is available, supported by a K2 study.
The study was performed pre-GLP and no guideline is mentioned. Very limited data is provided on the methods and results, only a 1 page summary. No data on test substance composition or purity. Full evaluation of the validity of this study is not possible.
The hair was clipped from the back of each rabbit. The skin was abraded for 1/2 of the rabbits in each group. The test material was applied to the backs in appropriate doses and the site of application was covered with gauze bandaging and occluded with Saran Wrap.
pre-GLP
- Weight at study initiation: 2325 to 2960 grams
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Photoperiod (hrs dark / hrs light): no data
IN-LIFE DATES: no data
- Area of exposure: back
- % coverage: no data
- Type of wrap if used: The site of application was covered with gauze bandaging and occluded with Saran Wrap.
- Washing (if done): no data
- Time after start of exposure: no data
- Amount(s) applied (volume or weight with unit): no data
- Concentration (if solution): no data
- Constant volume or concentration used: no data
- For solids, paste formed: no data
1000, 2000, 4000, 8000 mg/kg bw
- Frequency of observations and weighing: animals were observed for mortality on a daily basis, no data on body weight.
- Necropsy of survivors performed: no data
>= 8 000 mg/kg bw
The acute dermal toxicity in male and female albino rabbits would be greater than 8000 mg/kg bw.
Eight New Zealand White rabbits, equally divided as to sex, weighing 2325 to 2960 grams were exposed. The hair was clipped from the back of each rabbit. The skin was abraded for 1/2 of the rabbits in each group. The test material was applied, as received, to the backs in doses of 1000, 2000, 4000, 8000 mg/kg bw. The site of application was covered with gauze bandaging and occluded with Saran Wrap.
The rabbits were observed for death at 24 hours and daily thereafter for a total of 14 days. None of the animals died, no other effects reported. The acute dermal toxicity in male and female albino rabbits would be greater than 8000 mg/kg bw.
The registered substance was not acutely toxic to rats when tested by the oral gavage route. Based on the pattern of use ingestion by humans is unlikely.
An acute toxicity study via the dermal route was not performed since this is scientifically unjustified, for details see above. A weight of evidence approach is scientifically applicable for chemically comparable organic peroxides and allows one to conclude also a dermal LD50 > 2000 mg/kg bw for the untested organic peroxide.
An acute toxicity study via the inhalation route was not performed and can be waived according to REACH Annex VIII since exposure via this route is unlikely.
Justification for selection of acute toxicity – oral endpoint
K1:The study is performed according to OECD guidelines and GLP. LD50 >2000 mg/kg bw, no mortalities occurred.
Justification for selection of acute toxicity – inhalation endpoint
In accordance with column 2 of REACH Annex VIII, the test for acute inhalation toxicity (required in section 8.5) does not need to be conducted. Testing by the inhalation route is not appropriate since exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to droplets of an inhalable size. The vapour pressure is very low (see section 4.6) and the pattern of use does not lead to the formation of droplets of an inhalable size.
Justification for selection of acute toxicity – dermal endpoint
Numerous organic peroxides have been tested in acute dermal toxicity tests (41 organic peroxides covering all chemical subgroups/families of organic peroxides, excluding hydroperoxides). Experimental data of all of these organic peroxides, (except hydroperoxides), show no toxic effects at dermal application up to the tested concentration limit of 2000 mg/kg bw and show for this reason an acute dermal toxicity of >2000 mg/kg bw. Therefore, a weight of evidence approach is scientifically applicable for chemically comparable organic peroxides and allows one to conclude also a dermal LD50 > 2000 mg/kg bw for the untested organic peroxide, supported by the 1976 test results. Additional testing for such organic peroxides is therefore not required and would not be in line with animal welfare legislation.
Based on the results of the acute oral toxicity study, the data is conclusive but not sufficient for classification.