Liquid Chromatographic Determination of Dexamethasone and Fluoroquinolones; in vitro Study

A precise, accurate and sensitive liquid chromatographic method is presented for the simultaneous analysis of moxifloxacin, levofloxacin, ciprofloxacin and dexamethasone in reference drugs, ophthalmic dosage form and in physiological fluids. Separation was achieved on a C-18 analytical column with acetonitrile-phosphate buffer (35:65 v/v) as mobile phase which was pumped isocratically at a flow rate of 1.0 mL min(-1) and monitored at 254 nm wavelength. The calibration curve was linear in range of 40-10 000 ng mL(-1). Test results in pharmaceutical and physiological samples showed excellent drug recovery (96.5-102.3 %) with good precision (0.81-2.3 % RSD). Test results were linear to sample concentration and correlation coefficient was more than 0.9990. The small value of quantification and detection levels showed the method to be sensitive enough for use in clinical and industrial investigations of all the mentioned drugs.