Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

Based on the results from an in-vitro study with isobutyl acrylate and in-vivo data from the structural analogue n-butyl acrylate, it can be presumed that isobutyl acrylate will be rapidly absorbed and metabolized after oral exposure in rats. The major portion of IBA will be hydrolysed by carboxyesterase to acrylic acid and iso-butanol. The subsequent metabolism follows that for acrylic acid, and involves metabolism to carbon dioxide via the propionate degradation pathway (acrylic acid --> 3-hydroxypropionic acid --> malonyl semialdehyde --> acetyl S CoA --> --> tricarboxylic acid cycle --> --> CO2). Metabolism of iso-butanol proceeds via the alcohol and aldehyd dehydrogenase pathway.

Discussion on bioaccumulation potential result:

In vitro studies:

Isobutyl acrylate was tested for relative rates of hydrolysis by a representative mammalian esterase (Porcine hepatic esterase). At concentrations of 0.2, 0.5 and 2.0 mM, conversion rates ranged between 45 - 47 μmol/min/mg protein (3 - 27 %) after 2 minutes, and 38 – 49 μmol/min/mg protein (7 - 57 %) after 5 minutes of incubation at 37°C (BASF AG, 2001). Thus, IBA was rapidly hydrolysed by hepatic esterase activity under in-vitro conditions. The results of this study indicate that isobutyl acrylate and n-butyl acrylate are hydrolyzed at comparable rates by a representative mammalian enzyme.

In vivo studies:

There are no in vivo studies for isobutyl acrylate available, but sufficient information on the structurally-related n-Butyl acrylate.

After oral administration (gavage), n-Butyl [2,3-14C]-acrylate was rapidly absorbed and metabolized in male Fischer 344 rats (75 % was eliminated as CO2, approximately 10 % via urine and 2 % via faeces). The major portion of n-butyl acrylate was hydrolysed by carboxyesterase to acrylic acid and n-butanol and eliminated as CO2. A smaller portion was conjugated with endogenous GSH to be subsequently excreted as mercapturic acids in the urine (Sanders, 1988).

After i.v. administration, the labelled n-butyl acrylate was rapidly absorbed and metabolized. The acrylate moiety was metabolized primarily to CO2, accounting for elimination of up to 45 % of the administered radiolabel. The second major route of elimination was in urine, with only trace amounts in faeces and as volatiles (Sanders, 1988).