Sulphuric acid, compound with graphite

Endpoint summary

Description of key information

The aim of the study was to test the toxic effect of the test item SAT Graphite after repeated oral administration in Wistar rats in a 90-day toxicity study. The test item was administered daily by oral gavage to 10 male and 10 female Wistar rats of the high, medium and low dose groups at concentrations of 1000, 250 and 62,5 mg/kg BW/day over a period of 90 days. Of these suspensions, 5 mL/kg BW was administered daily to each animal. Individual dose volumes were calculated from the latest actual body weight data. Additionally, as a control, 10 male and 10 female animals of the vehicle group received 5 mL/kg BW of the vehicle. Test substances were administered to rats of 6 - 7 weeks of age at the start of the in-life phase.

Rationale for the dose levels:

In preparation for this study a dose range finding (DRF) study with dose escalation was performed. Hence, the test item was administered daily by oral gavage at escalating dose levels over a time period of 18 days. Doses were increased every three day; the highest dose (1000 mg/kg BW) was applied for six days. No acute toxicological effects were observed in the study. In accordance with the Sponsor, and based on the regulatory requirements, the maximum dose for the 90-day toxicity study was 1000 mg/kg body weight. For the endorsed two lower dose-levels a factor of 4 was chosen, to ensure an appropriate NOAEL for the test item.

In the main test the test substances were administered to rats of 6 - 7 weeks of age at the start of the in-life phase. The first day of application was indicated as day 1. During the in-life phase, viability, general and detailed clinical signs, food and water consumption, body weight, grip strength and reactivity to sensory stimuli were monitored. Before treatment and at the end of the in-life phase an ophthalmological examination was performed at least on the high dose and the vehicle group animals. At the end of the treatment period, blood samples from all animals were collected to acquire data on the hematology and clinical biochemistry. Subsequently, all animals were sacrificed and examined by gross necropsy. Tissues and organs were preserved and processed for histopathological examination.

In the course of this test following results have been observed:

Fatalities: There were no test item related fatalities.

General and detailed clinical signs: Throughout the course of the study no test item related effect was observed in any experimental animal group.

Body weight, food and water consumption: No abnormal differences regarding body weight and body weight gain were observed between all test item treated animals (neither male nor female) and the respective vehicle control animals. No test item related changes in food and water consumption of all test item treated animals (males and females) were observed throughout the whole in-life phase when compared to their respective control animals.

Hematology and clinical biochemistry: In all test animals no relevant or adverse test item induced effects on any hematological parameter could be detected. Most prominently in the high dose groups (males and females) some changes in clinical biochemistry parameters were observed. The results from the histopathological examination of selected organs revealed no positive correlates. Therefore all observed clinical parameters were regarded as not adverse.

Necropsy: In summary, all macroscopic findings were regarded as not treatment related. Except the relative (not absolute) heart weight of the female low dose group, no significant changes in organ weights were noted.

Histopathological examination: There were no microscopic observations that were attributed to the test item, that were consistent with the spectrum of background pathology in Wistar Han rats of this age.

As a conclusion it can therefore be stated that a continuous oral administration of the test item SAT Graphite to Wistar rats at dose levels of 1000, 250 and 62,5 mg/kg bodyweight over a period of 91 days resulted in some minor changes in clinical biochemistry blood parameters and lymphoid organs. However, in conclusion with the histopathological result these particular observations were toxicologically considered as not adverse. For this reason, the NOAEL of SAT Graphite after administration over 91 days is determined at 1000 mg/kg BW per day.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

System:

other: oral gavage

Additional information