RAPID LIQUID-CHROMATOGRAPHIC ASSAY OF CIPROFLOXACIN IN HUMAN AQUEOUS-HUMOR

A simple, selective and sensitive method has been developed to determi ne ciprofloxacin in human aqueous humor. Separation of ciprofloxacin w as carried out with pipemidic acid as internal standard using a Novapa k C-18 reversed-phase cartridge column (100 x 8 mm i.d., particle size 4 mu m) and a mobile phase consisting of methanol-acetonitrile-citric acid (0.4 M) (3:1:10, v/v/v) at a flow rate of 1 ml min(-1). The colu mn effluent was monitored with fluorescence detection at 278 nm (excit ation) and 450 nm (emission) after direct injection. The retention tim es were 4.88 min for pipemidic acid and 7.52 min for ciprofloxacin. Th e within-day and day-to-day reproducibilities were less than 7% for ci profloxacin at 0.1 and 1 mu g ml(-1) (n = 6). The mean recovery from a queous humor was found to be 101.37 +/- 6.7% for ciprofloxacin at 0.1 mu g ml(-1) (n = 6) and the detection limit corresponding to a signal- to-noise ratio of 2.5:1 was 250 pg ml(-1). The method was shown to be suitable for determining ciprofloxacin levels in human aqueous humor s amples.