Determination of moxifloxacin in growth media by high-performance liquid chromatography

A direct injection high-performance liquid chromatographic method with column switching has been developed to determine moxifloxacin in Mueller-Hinton broth. A LiChrocart 4-4 pre-column filled with a LiChrospher 100 RP 18, 5 microm and a 150 x 4.6 mm I.D. column packed with a Supelcozil ABZ+ Plus were used and led to a retention time of 5.70 min. Fluorescence detection allowed one to reach a quantification limit of 0.05 microg/ml with a 100-microl sample size. The standard curves were linear from 0.05 to 3.2 microg/ml. Intra- and inter-day imprecisions within the linearity range were < or =4.76 and < or =5.75%, respectively. The mean relative errors for the same day and the day-to-day inaccuracies ranged from -2.93 to +4.50% and from -1.10 to +6.00%, respectively. The method was demonstrated to be useful for pharmacokinetic-pharmacodynamic studies of moxifloxacin in an in vitro model.