The effect of static magnetic fields on the photohemolysis of human erythrocytes by ketoprofen.
Ultraviolet irradiation (lambda > 300 nm) of the nonsteroidal anti-inflammatory agent ketoprofen (KP, 3-benzoyl-alpha-methylbenzoacetic acid) in aqueous solution, pH 7.4, results in heterolytic decarboxylation of the drug to give 3-ethylbenzophenone (EtBP). Ketoprofen caused the photohemolysis of human erythrocytes probably as a result of lipid peroxidation. Application of a static magnetic field (250-1500 G) during UV (> 300 nm) irradiation of KP and erythrocytes significantly decreased the time required for photohemolysis. This observation suggests that KP-induced photohemolysis involves the initial generation of a triplet radical pair derived from the reaction of triplet state KP (or 3-EtBP) with erythrocyte component(s) probably lipids. The magnetic field increases the concentration and/or lifetime of free radicals that escape from the radical pair so that the critical radical concentration needed to initiate membrane damage and cause cell lysis is reached sooner. Spin-trapping studies with 2,6-dibromo-1-nitrosobenzene-4-sulfonate confirmed that the application of an external static magnetic field increased the concentration of radicals released during the photolysis of either KP or 3-EtBP dissolved in organized media such as sodium dodecylsulfate micelles.
Chignell
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CF
Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA. chignell@niehs.nih.gov
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D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D004574:Electromagnetic Fields; D004912:Erythrocytes / Q000187:drug effects* / Q000528:radiation effects; D006461:Hemolysis / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D007660:Ketoprofen / Q000009:adverse effects*; D010777:Photochemistry; D014466:Ultraviolet Rays
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007660:Ketoprofen