STRUCTURE ELUCIDATION OF A PHOTODEGRADATION PRODUCT OF CIPROFLOXACIN

In the photochemical degradation of ciprofloxacin, 1 uoro-1,4-dihydro- 4-oxo-7-(piperazinyl)-3-quinolone carboxylic acid: two major decomposi tion products are formed in-acidic solution. The main degradation prod uct, after both artificial and daylight exposure, was 7-amino-1 -cycio plopyl-6-fluoro- 1,4-dihydro-4-oxo-3-quinolone carboxylic acid. This p roduct was also the dominating compound after more than 5 h irradiatio n with a high-pressure mercury lamp in aqueous solutions at pH less th an or equal to 2 when the solvent additionally contained water-miscibl e organic solvent. The structure of the isolated compound was elucidat ed on the basis of the chemical behaviour in thin-layer and high-perfo rmance liquid chromatography, and of information from infrared, ultrav iolet, mass and nuclear magnetic resonance spectra. (C) 1997 Elsevier Science B.V.