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Description of key information

In the general toxicity element of an OECD 422 screening test in rats, Tetrabutane elicited no systemic toxic effect at dosages of 100, 300 or 1000 mg/kg/day. The NOAEL for repeat dose oral toxicity is 1000 mg/kg/day.
A 90-day repeated dose toxicity study has not been conducted on Tetrabutane. However, in the complete absence of any toxic effect at the limit dosage of 1000 mg/kg/day in the OECD 422 screening study, it is unlikely that Tetrabutane will represent a toxic risk by more prolonged oral exposure.
Repeated dose studies have not been undertaken by the dermal or inhalation routes. The physical properties of Tetrabutane and its low toxicity by oral administration, indicates that the substance represents a low toxic risk by both the dermal and inhalation routes.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat

Additional information

Oral route

A study was performed at the Laboratories of Huntingdon Life Sciences, Eye, UK., to investigate the sub-acute toxicity of the test substance Tetrabutane when administered to rats by oral gavage. Three groups, each comprising five male and five female rats, received Tetrabutane once daily at dosages of 100, 300 or 1000 mg/kg/day for a period of five complete weeks before termination. A similarly constituted Control group received the vehicle, corn oil, at the same volume-dose for the same duration.

Throughout the study, data was recorded on clinical condition, detailed physical and arena observations and bodyweight Food consumption was recorded during Weeks 1 and 2 and sensory reactivity, grip strength, motor activity, haematology and blood chemistry during Week 4. Organ weight, macroscopic and microscopic pathology investigations were undertaken at termination. The study was conducted to GLP.

There were no effects for general toxicity at dosages up to 1000 mg/kg/day. Slightly higher overall bodyweight and food consumption was recorded amongst males and females receiving 100, 300 or 1000 mg/kg/day, when compared with the controls, although the biological significance of these findings is uncertain.

Based on the results of this study, it was concluded that the No-Observed-Adverse-Effect-Level (NOAEL) for general toxicity in adult male and female rats was 1000 mg/kg/day Tetrabutane.

The study is considered acceptable for classification and satisfies the guideline requirements for a rat repeated dose toxicity screening test.

Dermal route

The high water/octanol partition co-efficient of Tetrabutane (Log Pow 9.6 to 10.1) and the absence of systemic effects following acute dermal exposure indicates that no significant absorption occurs through the skin. In addition, Tetrabutane shows low systemic toxicity following repeated oral administration to rats. It is therefore considered unlikely that Tetrabutane will represent a toxic risk by repeated dermal exposure.

Inhalation route

Tetrabutane has a low vapour pressure (< 1 hPa at 20°C) and a high boiling point (278 °C at 1013 hPa), and would be expected to result in only minimal inhalation exposure.  In addition, Tetrabutane shows low systemic toxicity following repeated oral exposure to rats. It is therefore considered unlikely that Tetrabutane will represent a toxic risk by repeated inhalation exposure.

 

Justification for classification or non-classification

No classification for repeated dose toxicity is indicated according to the classification, labelling and packaging (CLP) regulation (EC) No 1272/2008.