Registration Dossier

Dose descriptor:

NOAEL

200 mg/kg bw/day

SUMMARY

Introduction.

The study was designed to investigate the systemic toxicity and potential adverse effects of the test material on reproduction (including offspring development) and complies with the recommendations of the OECD Guidelines for Testing of Chemicals No. 422 “Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test” (adopted 22 March 1996).

This study was also designed to comply with Commission Regulation (EC) No 440/2008 of 30 May 2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).

Methods.

The test material was administered by gavage to three groups, each of ten male and ten female Wistar Han™:HsdRccHan™:WIST strain rats, for up to fifty-four consecutive days (including a two week maturation phase, pairing, gestation and early lactation for females), at dose levels of 50, 100 and 200 mg/kg/day. A control group of ten males and ten females was dosed with vehicle alone (Arachis oil BP).

Clinical signs, behavioural assessments, bodyweight development, food and water consumption were monitored during the study. Haematology and blood chemistry were evaluated at termination on five selected males and females from each dose group.

Pairing of animals within each dose group was undertaken on a one male: one female basis within each treatment group on Day 15 of the study, with females subsequently being allowed to litter and rear their offspring to Day 5 of lactation.

During the lactation phase, daily clinical observations were performed on all surviving offspring, together with litter size and offspring weights and assessment of surface righting reflex.

Extensive functional observations were performed on five selected males from each dose group after the completion of the mating phase, and for five selected parental females from each dose group on Day 4post partum.

Males were terminated on Day 43, followed by the termination of all surviving females and offspring on Day 5post partum. All animals were subjected to a gross necropsy examination and histopathological evaluation of selected tissues was performed.

Results.

Mortality.One female treated with 200 mg/kg/day was found dead on Day 5. There were no further unscheduled deaths during the study.

Clinical Observations.Animals of either sex from all treatment groups showed episodes of increased salivation immediately post or one hour post dosing throughout the treatment period.

Behavioural Assessment.There were no treatment-related changes in the behavioural parameters measured.

Functional Performance Tests.There were no treatment-related changes in functional performance.

Sensory Reactivity Assessments.There were no treatment-related changes in sensory reactivity.

Bodyweight.Animals of either sex treated with 200 mg/kg/day showed actual bodyweight losses during Week 1 of treatment. Males from this treatment group continued to show a reduction in bodyweight gain during Week 2. Females treated with 200 mg/kg/day showed actual bodyweight losses during the first week of treatment.

No such effects were detected in animals of either sex treated with 100 or 50 mg/kg/day.

Food Consumption.No adverse effect on food consumption was detected. Food efficiency was however reduced for males treated with 200 mg/kg/day during the first two weeks of treatment and for females from this treatment group during the first week of treatment.

No such effects in food efficiency were detected in animals of either sex treated with 100 or 50 mg/kg/day.

Water Consumption.No intergroup differences were detected.

Haematology.No toxicologically significant effects were detected in the haematological parameters measured.

Blood Chemistry.No toxicologically significant effects were detected in the blood chemical parameters measured.

Reproductive Performance:

Mating and Fertility.There were no treatment-related effects on mating or conception rates for treated animals.

One female treated with 50 mg/kg/day was found to be non-pregnant. One control and two females treated with 200 mg/kg/day failed to show any positive evidence of mating but subsequently gave birth to live young.

Gestation Length.There were no differences in gestation lengths. The distribution for treated females was comparable to controls.

Litter Responses:

Offspring Litter Size and Viability.Of the litters born, litter size at birth and subsequently on Days 1 and 4post partumwere comparable to controls.

Offspring Growth and Development.Litter weights at Day 4post partumwere reduced in females treated with 200 mg/kg/day.

No such effects were detected in litters from females treated with 100 or 50 mg/kg/day.

Litter observations.No clinically observable signs of toxicity were detected for offspring from all treatment groups.

Organ Weights.No toxicologically significant effects were detected in the organ weights measured.

Necropsy.No toxicologically significant effects were detected.

Histopathology.The following treatment-related effects were detected:

STOMACH:Hyperkeratosis of the forestomach was evident in animals of either sex treated with 200 and 100 mg/kg/day. Ulceration was also noted in one male and two females treated with 200 mg/kg/day. Further changes in the forestomach were identified as erosion in one female treated with 200 or 100 mg/kg/day, abscesses in the muscular layer in one male treated with 200 mg/kg/day and inflammation in the muscular layer in one male treated with 100 mg/kg/day and one female treated with 200 mg/kg/day.

Discussion

The oral administration of Reaction mass of bis(epoxyethyl) benzene and (ethylphenyl) oxirane to rats for a period of forty-two days for males and up to fifty-four days for females (including two weeks pre-mating, gestation and early lactation period) at dose levels of 0, 50, 100 or 200 mg/kg/day produced no toxicologically significant effects in the reproductive parameters which were measured. Three females in the high dose group did show inconclusive individual isolated effects,but overall no treatment-related effects were observed for reproductive toxicity. .

Clinically observable signs identified as increased salivation were observed during the daily clinical observations in all treatment groups. Treatment related microscopic findings representing a local irritant effect were confined to the stomach at 200 and 100 mg/kg/day and examination revealed hyperkeratosis, ulceration/erosion and inflammation/abscesses of the forestomach. Observations of this nature are commonly observed following the oral administration of irritant test material formulations.

Conclusion

The oral administration of Reaction mass of bis(epoxyethyl) benzene and (ethylphenyl) oxirane to rats by gavage, at dose levels of 200, 100 and 50 mg/kg/day, resulted in treatment-related effects at 200 and 100 mg/kg/day. No such effects were detected at 50 mg/kg/day therefore the 'No Observed Effect Level' (NOEL) for systemic toxicity was considered to be 50 mg/kg/day.

As no adverse treatment-related effects were observed for reproduction, the ‘No Observed Adverse Effect Level’ (NOAEL) for reproductive/developmental toxicity was considered to be 200 mg/kg/day.

Short description of key information:
The oral administration of Reaction mass of bis(epoxyethyl) benzene and (ethylphenyl) oxirane to rats by gavage, at dose levels of 200, 100 and 50 mg/kg/day, resulted in treatment-related effects at 200 and 100 mg/kg/day. No such effects were detected at 50 mg/kg/day therefore the 'No Observed Effect Level' (NOEL) for systemic toxicity was considered to be 50 mg/kg/day.
No adverse treatment-related effects were observed for reproduction, therefore, a ‘No Observed Adverse Effect Level’ (NOAEL) for reproductive toxicity was considered to be 200 mg/kg/day.

The oral administration of Reaction mass of bis(epoxyethyl) benzene and (ethylphenyl) oxirane to rats for a period of forty-two days for males and up to fifty-four days for females (including two weeks pre-mating, gestation and early lactation period) at dose levels of up to 200 mg/kg/day resulted in no toxicologically significant effects in the reproductive and developmental parameters which were measured during the course of the study. , As no adverse treatment-related effects were observed for reproduction/development , a ‘No Observed Adverse Effect Level’ (NOAEL) for reproductive/developmental toxicity was considered to be 200 mg/kg/day.