2-chlorobenzaldehyde

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Additional information

In an experimental study of Rietveld et al. (1988) radiolabelled 14C-2-chlorobenzaldehyde was applied intravenously (25 µl/kg) or intraperitoneally (37.5 µl/kg) to male Wistar rats. Radioactivity was measured in blood, urine, faeces and exhaled air. The test item was rapidly and completely eliminated within 24 hours after intravenous and intraperitoneal application to rats. Excretion was mainly via urine (about 98%) and only small amounts were found in the faeces and exhaled air. Plasma elimination followed a bi-exponential fashion, the 14C half-life during the first elimination phase was 15.6 min.

A publication of Seutter-Berlage et al. (1982) showed that after a single dose of o-chlorobenzaldehyde (0.4 mmol per animal) to rats an enhanced urinary thioether excretion was observed in the first 24 h after dosing (increase in SH: 30.38µmol or 6.9% of dose; 52.25µmol or 13.1% of dose). Therefore 20% of the applied dose was excreted in the urine as secondary metabolites in 24 hours.

Furthermore, mercapturic acids were isolated from the urines after continuous dosing with o-chlorobenzaldehyde. The structures of the methyl esters of the isolated substances were confirmed by NMR and mass spectra and were identified as the arylmethyl thioethers of N-acetylcysteine.

A second publication (Rietveld et al. 1986) revealed a benzylmercapturic acid excretion in the urine of 7.6 % of the dose after i.p. administration of 2-chlorobenzaldehyde to rats.

Additionally, Rietveld et al. (1988) showed that cutaneously administered 14C-2-chlorobenzaldehyde (75 µI/kg) was well absorbed by the skin of rats. The major portion of radioactivity was excreted in the urine. Urinary excretion of the radioactivity was found about 45% within the first 24 h post dosing: About 15% of the 75 µl/kg dose of 14C-2-chlorobenzaldehyde was found in the glasscup (semiocclusive cover) and on the skin. The principal metabolite in rat urine was 2-chlorohippuric acid. No part of the urinary radioactivity was present as parent compound and there was no evidence of storage in the skin or skin toxicity of 2-chlorobenzaldehyde following cutaneous application.

Altogether these publications show that 2-chlorobenzaldehyde is extensively biotransformed in mammalians after different routes of application and is mainly excreted in the urine as secondary metabolites in the first 24 hours after dosing.