title: High-performance liquid chromatographic determination and identification of acyl migration and photodegradation products of furosemide 1-O-acyl glucuronide.
abstract: Stability of furosemide glucuronide, the major metabolite of furosemide, was studied in order to accurately assess the glucuronidation of furosemide. Furosemide glucuronide was purified by high-performance liquid chromatography, and the mass spectrum of furosemide glucuronide showed the molecular ion peaks [M-H]- at 505 and 507 (m/z). Furosemide glucuronide was photodegraded to the compound, which was shown more hydrophilic than furosemide glucuronide by high-performance liquid chromatography assay. The photodegradation product of furosemide glucuronide was hydrolyzed to one of the photodegradation products of furosemide by beta-glucuronidase, indicating that the photodegradation product of furosemide glucuronide possessed a glucuronic acid moiety. Furthermore, the mass spectrum of the photodegradation product of furosemide glucuronide exhibited molecular ion peaks [M-H]- at 487 and [M-2H+2Na]- at 509, indicating the chlorine displacement of furosemide glucuronide by a hydroxyl group. Furosemide glucuronide was unstable in an aqueous solution (pH=7.4), and presumed acyl migration isomers of furosemide glucuronide (furosemide glucuronide-isomers) were detected by high-performance liquid chromatography equipped with photodiode array UV detector. The UV spectra of seven furosemide glucuronide-isomers were closely similar to that of furosemide glucuronide but not furosemide. Exposing a mixture of furosemide glucuronide and furosemide glucuronide-isomers to light resulted in the production of new compounds. UV spectra of photodegradation products of furosemide glucuronide-isomers were closely similar to those of photodegradation product of furosemide glucuronide. These results suggested that furosemide glucuronide-isomers were also photodegraded, resulting in the displacement of chlorine by a hydroxyl group as in furosemide glucuronide.
authors.affiliation: Department of Biopharmaceutics, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mizuma
authors.forename: L Z
authors.initials: LZ
authors.lastname: Benet
authors.forename: E T
authors.initials: ET
authors.lastname: Lin
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005665:Furosemide / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D005966:Glucuronidase / Q000378:metabolism; D013058:Mass Spectrometry; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: C036234:furosemide glucuronide; D005665:Furosemide; D005966:Glucuronidase