HPLC Determination of Gatifloxacin in Whole Blood

A method of HPLC determination of gatifloxacin (GXTC) in whole blood with fluorescence detection and using ciprofloxacin (CPXC) as internal standard was proposed.GXTC was extracted from the blood sample with PBS of pH 7.0 and purified by SPE microcolumn.A mixed solution of formic acid and methanol (4 to 96 by vol.) was used as eluant,the eluate was dried by N2-blowing and the residue taken up with 1.0 mL of methanol,from which 10.0 μL was alquoted for HPLC determination.The cloversil C18 column (150 mm×3.0 mm,5 μm) was used as the stationary phase,and a mixture of methanol,acetonitrile and formic acid solution (2+998),mixed in the ratio of 15 to 15 to 70 by volume,was used as the mobile phase.FI rescence detections were made at the wavelengths of (λex) 288 nm and (λem) 478 nm.Linear relationship between values of ratio of peak areas of GTXC/CPXC and mass concentration of GTXC was obtained in the range of 15.0-240.0 μg·L-1.Lower limit of determination (10S/N) of the method was found to be 15.0 μg·L-1.Values of recovery found at different concentration levels were in the range of 97.0%-102.0% within-day precision was tested,and values of RSD′s (n=6) found were less than 6.0%.