Identification of metabolites of azaperone in horse urine

Article abstract of DOI:10.1021/js950205j

Two metabolites of the tranquilizer azaperone were extracted from alkalinized horse urine after treatment with β-glucuronidase/sulfatase from limpets (Patella vulgata). The metabolites were identified by a combination of independent chemical synthesis and GC/MS and ¹H NMR analysis. The metabolites were identified as 1-(fluorophenyl)-4-[4-(5-hydroxy-2-pyridinyl)- 1-piperazinyl]-1-butanol, designated as 5'-hydroxyazaperol, and 1- (fluorophenyl)-4-[4-(5-hydroxy-2-pyridinyl)-1-piperazinyl]-1-butanone, designated as 5'-hydroxyazaperone. A TLC screening test was developed for detecting both metabolites in basic extracts of horse urine treated with β- glucuronidase/sulfatase. The screening test was used to detect azaperone metabolites in extracts of horse urine collected for 24 h alter intravenous administration of azaperone. The administration of azaperone to horses was confirmed by GC/MS identification of 5'-hydroxyazaperone and 5'- hydroxyazaperol from basic extracts of horse urine treated with β- glucuronidase/sulfatase. The extracted metabolites were treated with bis(trimethylsilyl)acetamide to produce trimethylsilyl (TMS) ether derivatives, and mass spectra and retention times were compared to those of the synthesized metabolites treated in the same manner.