title: A rapid and simple high-performance liquid chromatography method for the determination of human plasma levofloxacin concentration and its application to bioequivalence studies.
abstract: A high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) for the determination of levofloxacin in human plasma is described. Neutralized with phosphate buffer (pH 7.0), the sample (0.1 mL) was extracted with dichlormethane (1 mL). After voltex-mixing and centrifuged at 3000g for 6 min at 4 degrees C, the upper aqueous layer was aspirated using a micro vacuum pump and the organic layer was directly transferred to a clean test tube without pipetting. The organic solvent was evaporated and the residues were reconstituted with the mobile phase. Levofloxacin and terazosin (internal standard, IS) were chromatographically separated on a C(18) column with a mobile phase containing phosphate buffer (pH 3.0, 10 mm), acetonitrile and triethylamine (76:24:0.076, v/v/v) at a flow rate of 1 mL/min. The analytes were detected using fluorescence detection at an excitation and emission wavelength of 295 and 440 nm, respectively. The linear range of the calibration curves was 0.0521-5.213 microg/mL for levofloxacin with a lower limit of quantitation (0.0521 microg/mL). The retention times of levofloxacin and terazosin were 2.5 and 3.1 min, respectively. Within- and between-run precision was less than 12 and 11%, respectively. Accuracy ranged from -6.3 to 4.5%. The recovery ranged from 86 to 89% at the concentrations of 0.0521, 0.5213 and 5.213 microg/mL. The present HPLC-FLD method is sensitive, efficient and reliable. The method described herein has been successfully used for the pharmacokinetic and bioequivalence studies of a levofloxacin formulation product after oral administration to healthy Chinese volunteers.
authors.affiliation: Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou 510080, People's Republic of China.
authors.forename: Zhi-Ling
authors.initials: ZL
authors.lastname: Zhou
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Xi-Yong
authors.initials: XY
authors.lastname: Yu
authors.forename: Huai-Yan
authors.initials: HY
authors.lastname: Peng
authors.forename: Zhi-Xin
authors.initials: ZX
authors.lastname: Shan
authors.forename: Shu-Zhen
authors.initials: SZ
authors.lastname: Chen
authors.forename: Qiu-Xiong
authors.initials: QX
authors.lastname: Lin
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Liu
authors.forename: Tie-Feng
authors.initials: TF
authors.lastname: Chen
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Zhou
authors.forename: Shu-Guang
authors.initials: SG
authors.lastname: Lin
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000097:blood*; D019540:Area Under Curve; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D006801:Humans; D064704:Levofloxacin; D008297:Male; D015242:Ofloxacin / Q000008:administration & dosage / Q000097:blood*; D011224:Prazosin / Q000031:analogs & derivatives / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods; D013050:Spectrometry, Fluorescence; D013810:Therapeutic Equivalency
chemical_list: D000900:Anti-Bacterial Agents; D064704:Levofloxacin; C041226:Terazosin; D015242:Ofloxacin; D011224:Prazosin