title: [Impurity analysis and their structure determination of gatifloxacin].
abstract: OBJECTIVE
  To analyse the impurities of gatifloxacin.
  
  
  METHODS
  The impurity of gatifloxacin were analysized and determinated by RP-HPLC/electrospray ionization mass spectrometry with a Zorbax SB-C18(4.6 mm x 150 mm ID, 5 microns). The mobile phase was 3% acetic acid/acetonitrile-3% acetic acid/water (15:85). The two compounds were synthesized: 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-methoxy-7-(1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMP) and 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-hydro-7-(3-methy-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMO). Their liquid chromatogram, UV, MS were compared with those of the impurity of gatifloxacin.
  
  
  RESULTS
  The mass of the impurity was 14 less than that of gatifloxacin. It means the impurity was CH2 less than gatifloxacin. The tR (HPLC), UV and MS of DMP were the same as those of the impurity of gatifloxacin.
  
  
  CONCLUSIONS
  Based on the tR (HPLC), UV and MS, the impurity of gatifloxacin is confirmed as DMP.
authors.affiliation: Center for Instrumental Analysis, China Pharmaceutical University, Nanjing 210009, China. Honghua.zhou@sohu.com
authors.forename: Hong-hua
authors.initials: HH
authors.lastname: Zhou
authors.forename: Song-mei
authors.initials: SM
authors.lastname: Gao
authors.forename: Er-hua
authors.initials: EH
authors.lastname: Wang
authors.forename: Wen-bin
authors.initials: WB
authors.lastname: Shen
authors.forename: Long-sheng
authors.initials: LS
authors.lastname: Sheng
mesh_terms: D000890:Anti-Infective Agents / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004340:Drug Contamination; D024841:Fluoroquinolones / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification*; D000077734:Gatifloxacin; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: C479311:1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-(1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D000077734:Gatifloxacin