2-propylheptan-1-ol

Endpoint summary

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Additional information

There are no data concerning toxicokinetic of 2-Propylheptan-1-ol available.

 

Information of toxicokinetic, metabolism and distribution of linear and branched chain alcohols is given in the OECD SIDS initial assessment report for SIAM 22 Oxo Alcohols C9 to C13 (18. - 21 .04.2006). 2-Propylheptan-1-ol belongs also to the group of branched alcohols. Therefore, this information could be assigned for 2-Propylheptan-1-ol.

Linear and branched chain alcohols exhibit similar patterns of absorption, metabolism, and excretion. Both linear and branched aliphatic alcohols are absorbed through the gastrointestinal tract and are rapidly eliminated from the blood (DeBruin, 1976; Lington and Bevan, 1994). Plasma half-lives are normally difficult to measure since many of the low molecular weight metabolites (e.g. aldehydes, carboxylic acids) are endogenous in humans (Lington and Bevan, 1994).

Linear and branched chain alcohols are initially oxidized to their corresponding aldehydes and further to their corresponding carboxylic acids by high capacity NAD+/NADH-dependent enzymes, which are then metabolized to carbon dioxide via the fatty acid pathways and the tricarboxylic acid cycle (Feron et al., 1991; Parkinson, 1996a; Voet & Voet, 1990).

Alcohol dehydrogenase (ADH) enzymes are the cytosolic enzymes that are primarily responsible for the oxidation of alcohols to their corresponding aldehydes. Alcohols also can be oxidized to aldehydes by non-ADH enzymes present in the microsomes and peroxisomes, but these are generally quantitatively less important than ADH. Aldehyde dehydrogenases (ALDH) oxidize aldehydes to their corresponding carboxylic acids. Branched-chain aliphatic alcohols and aldehydes have been shown to be excellent substrates for ADH and ALDH (Albro, 1975; Blair & Bodley, 1969; Hedlund & Kiessling, 1969). As carbon chain length increases, the rates of ALD-mediated oxidation also increase (Nakayasu et al., 1978).

The metabolism of branched-chain alcohols, aldehydes, and carboxylic acids containing one or more methyl substituents is determined primarily by the position of the methyl group on the branched-chain. Alcohols and aldehdydes are rapidly oxidized to their corresponding carboxylic acids. The branched-chain acids are metabolized via beta-oxidation in the longer branched-chain followed by cleavage to yield linear acid fragments which are then completely metabolized in the fatty acid pathway or the tricarboxylic acid cycle. Higher molecular weight homologues (>C10), may also undergo a combination of ω-, ω-1 and β-oxidation, and selective dehydrogenation and hydration to yield polar metabolites which are excreted as the glucuronic acid or sulfate conjugates in the urine and, to a lesser extent, in the feces (Diliberto et al., 1990). Thus, the principal metabolic pathways utilized for detoxication of these branched-chain substances are determined primarily by four structural characteristics: carbon chain length, and the position, number, and size of alkyl substituents.