title: Newly discovered photodegradation products of nifedipine in hospital prescriptions.
abstract: New photodegradation products of nifedipine (1) have been isolated. They were found in tablets dispensed in the pulverized form by hospitals. 1 decomposed concurrently into six components after storage of 30 days under exposure to normal room light. The main photoproduct was a nitroso derivative (2) and others were minor. Preparative thin-layer chromatography has been used to isolate the six photodegradation products. The chemical structures of these isolated compounds were identified or estimated by comparison with authentic samples and/or using UV, IR, 1H NMR, mass spectroscopy, melting point determination, and elementary analysis. From these analyses, it was found that 1 was converted into a cis-azoxy derivative (4), a trans-azoxy derivative (5), a N,N'-dioxide derivative (6) and a lactam derivative (7) in addition to 2 and a nitro derivative (3). Furthermore, it is proposed that 2 is mainly responsible for the formation of these new products (4-7) by photochemical condensation.
authors.affiliation: Department of Pharmacy, Asahikawa Medical College Hospital, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hayase
authors.forename: Y
authors.initials: Y
authors.lastname: Itagaki
authors.forename: S
authors.initials: S
authors.lastname: Ogawa
authors.forename: S
authors.initials: S
authors.lastname: Akutsu
authors.forename: S
authors.initials: S
authors.lastname: Inagaki
authors.forename: Y
authors.initials: Y
authors.lastname: Abiko
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D011307:Drug Prescriptions; D004356:Drug Storage; D008027:Light; D013058:Mass Spectrometry; D009543:Nifedipine / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D010607:Pharmacy Service, Hospital; D010777:Photochemistry; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013607:Tablets
chemical_list: D013607:Tablets; D009543:Nifedipine