Effect of omeprazole on bioavailability of an oral extended-release formulation of ciprofloxacin

The effect of omeprazole on the oral bioavailability and urinary exposure of the Depomed formulation of extended-release (ER) ciprofloxacin was studied. A two-way crossover study was conducted in healthy subjects. Subjects received either a single dose of ER ciprofloxacin 1000 mg or a single dose of ER ciprofloxacin 1000 mg following three days of treatment with omeprazole 40 mg. Blood and urine samples were collected over 36 hours, and ciprofloxacin concentrations were determined using high-performance liquid chromatography. Twenty-seven subjects (16 men, 11 women) received both treatments. The mean maximum concentration, mean area under the plasma-versus-concentration curve, and mean amount of ciprofloxacin excreted in urine were similar between the two treatments and met strict bioequivalence criteria. Omeprazole did not affect the plasma or urinary pharmacokinetics of an oral ER formulation of ciprofloxacin.