Solid-phase UV spectrophotometric method for determination of ciprofloxacin

A simple and inexpensive method for the determination of ciprofloxacin has been developed using solid-phase spectrophotometry. The intrinsic absorbance of ciprofloxacin fixed on a dextran-type cation-exchange resin, Sephadex SP C-25, was measured directly at 277 and 380 nm after packing the gel beads in a 1-mm cell. Using a sample volume of 10 ml, the calibration graph was linear over the range 0.05-0.3 μg ml⁻¹ with a R.S.D. of 1.11% (n=8). The sensitivity obtained is 40 times higher than that of the corresponding solution method. The method was applied to the determination of ciprofloxacin in pharmaceutical preparations and was validated by standard addition.