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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
Author(s) -
Condorelli G.,
Guidi G. De,
Giuffrida S.,
Sortino S.,
Chillemi R.,
Sciuto S.
Publication year - 1999
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1999.tb08136.x
Subject(s) - photodegradation , chromophore , chemistry , photochemistry , antibiotics , phototoxicity , photosensitizer , photocatalysis , biochemistry , catalysis , in vitro
The UVA irradiation of 9‐fluoro‐2,3‐dihydro‐10‐4′‐meth‐yl‐l'‐piperazinyl‐7‐oxo‐7H‐pyrido[l,2,3‐de]‐l,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.