title: Molecular mechanisms of photosensitization induced by drugs. XII. Photochemistry and photosensitization of rufloxacin: an unusual photodegradation path for the antibacterials containing a fluoroquinolone-like chromophore.
abstract: The UVA irradiation of 9-fluoro-2,3-dihydro-10-4'-methyl-1' -piperazinyl-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzo-thiazine-6-carboxylic acid, rufloxacin, a fluoroquinolone antibacterial that shows photosensitizing properties toward biological substrates, leads to formation of two main steady photoproducts characterized by a decarboxylation process and an opening of the piperazinyl ring, respectively. The deprotonation of the 10-piperazinyl group and the dissociation of the 6-carboxyl group of rufloxacin are strictly pH dependent. The photosensitizing activity was tested toward membranes as biological targets. Red blood cell hemolysis and lipid peroxidation were considered as markers of photosensitization. Ultraviolet A-induced damage is strongly influenced by the presence of oxygen, it is triggered by transient species, such as singlet oxygen and free radicals, photogenerated via rufloxacin irradiation, whereas no drug photoproduct is involved in the photosensitization process.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Catania, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Condorelli
authors.forename: G
authors.initials: G
authors.lastname: De Guidi
authors.forename: S
authors.initials: S
authors.lastname: Giuffrida
authors.forename: S
authors.initials: S
authors.lastname: Sortino
authors.forename: R
authors.initials: R
authors.lastname: Chillemi
authors.forename: S
authors.initials: S
authors.lastname: Sciuto
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000528:radiation effects; D024841:Fluoroquinolones; D006461:Hemolysis; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000494:pharmacology; D015363:Quinolones / Q000737:chemistry* / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D017319:Photosensitizing Agents; D015363:Quinolones; C060328:rufloxacin