title: RP-HPLC study of the degradation of diclofenac and piroxicam in the presence of hydroxyl radicals.
abstract: The effect of hydroxyl radical attack on two non-steroidal anti-inflammatory drugs (NSAIDs) was studied in vitro. Diclofenac and piroxicam were analysed by RP-HPLC after reaction with OH* free radicals to detect newly formed oxidation and/or degradation products. OH* free radicals were obtained by means of ferrous sulphate and ascorbic acid mixtures. During the reaction the mixtures were exposed to irradiation by a tungsten lamp to obtain an increased and more reproducible formation of hydroxyl radicals. The chromatographic profiles showed the formation of several new peaks for both diclofenac and piroxicam due to the presence of a number of degradation/oxidation products formed in the presence of OH* radicals.
authors.affiliation: Laboratorio di Chimica del Farmaco, Istituto Superiore di Sanita', Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Gaudiano
authors.forename: L
authors.initials: L
authors.lastname: Valvo
authors.forename: P
authors.initials: P
authors.lastname: Bertocchi
authors.forename: L
authors.initials: L
authors.lastname: Manna
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D016861:Cyclooxygenase Inhibitors / Q000032:analysis / Q000737:chemistry*; D004008:Diclofenac / Q000032:analysis / Q000737:chemistry*; D004355:Drug Stability; D017665:Hydroxyl Radical / Q000737:chemistry*; D010084:Oxidation-Reduction; D010894:Piroxicam / Q000032:analysis / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D010894:Piroxicam; D004008:Diclofenac; D017665:Hydroxyl Radical