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Key value for chemical safety assessment

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The low water solubility (< 1.2 mg/l), relatively high molecular weight (226 -338) and very high water/octanol partition coefficient (Log Kow 9.5 to 10.1) indicates that Tetrabutane has low potential for bioavailability. 

The low potential for absorption via the gastro-intestinal tract is supported by the absence of systemic reaction to treatment following acute oral exposure (Section 7.2.1). Minimal evidence of a systemic effect was also apparent in a subacute oral toxicity study in rats (Section 7.5.1).  However, the possibility of limited uptake via the lymphatic system cannot be excluded.

 

As Tetrabutane is a C16-C20 iso-alkane, the only primary metabolic pathways would involve carbon oxidation to give first alcohols and then carboxylic acids. This could occur at the terminal chain carbons and also at the branch methyl groups and at more than one carbon to give diols, dicarboxylic acids or combinations of the two. Some degradation of the carbon chain could occur up to the branch point by oxidative loss of two carbon units. The alcohols and carboxylic acids could be conjugated with glucuronic acid to give hydrophilic metabolites that would be readily excreted. None of the metabolites formed by these processes would be considered to have any gentoxic potential.

 

There is no toxicological evidence of distribution to the central nervous system, and the very high water/octanol partition coefficient would indicate only slight potential for tissue accumulation. 

 

The high partition co-efficient of Tetrabutane and the absence of systemic effects following acute dermal exposure (Section 7.2.2) indicates that no significant absorption occurs through the skin, and the low vapour pressure suggests that only a very low air concentration would be available for absorption via the lungs.