Based on the color reactions of gatifloxacin with acridine red,a new fading spectrophotometric method for the determination of gatifloxacin has been established.In pH 3.0～4.2 acid condition,gatifloxacin reacts with acridine red to form peachblow complexes.At the maximum fading wavelength of 538nm,the apparent molar absorption coefficient(ε) was 1.32×104 L·mol-1·cm-1.The Beer’s law was obeyed in the concentration range of 0.2mg/L～15.0 mg/L.The method has been applied to determine gatifloxacin in the practical samples with satisfactory results.
