Determination of Gemifloxacin in Human Serum by Online Heart-Cutting Liquid Chromatography: Application to Pharmacokinetic Study

Introduction: In this assay, a new selective online heart-cutting Liquid Chromatographic method was developed for the quantification of gemifloxacin in serum samples. Experiment: Separations were carried out with following systems; 1st chromatographic system consisting of 50 x 2.1 mm Pentafluorophenyl propyl pre-separation column with acetonitrile and 0.01 M orthophosphoric acid solution mixture (20:80) as mobile phase and the 2^nd chromatographic system consisting of 150 x 4.6 mm C18 separating column with methanol and 0.02 M ortho-phosphoric acid solution mixture (40:60) as mobile phase. Two systems were connected with a 6-port valve having 0.2 mL sample loop and separations were performed continuously through injections. Detection wavelength has been selected as 272 nm for both systems and moxifloxacin was used as internal standard. Extraction of drug substances from serum samples was performed using protein precipitation method with methanol and the calibration curve was linear over a concentration range of 0.5-5.0 μg/mL. The developed method was applied to serum samples collected from a volunteer who has received 320 mg gemifloxacin orally and pharmacokinetic parameters were calculated. Conclusion: In conclusion, the developed method is highly selective and reproducible and can be applied for the pharmacokinetic study of gemifloxacin.