[Analysis of impurity in caderofloxacin].
OBJECTIVE
To analyse the main impurity of caderofloxacin.


METHODS
The impurity of caderofloxacin was analysed and determinated by RP-HPLC/ESI/MS with a Zorbax SB-C18 (150 mm x 4.6 mm ID, 5 microns) column. The mobile phase was acetonitrile-0.5% acetic acid solution (17:83). A compound was synthesized: 1-cyclopropyl-8-(difluoromethoxy)-6-fluoro-1, 4-dihydro-7-(1-piperazinyl)-4-oxo-3-quinoline carboxylic acid (DMCA). Its HPLC chromatogram, UV and MS spectrum were compared with those of the impurity in caderofloxacin.


RESULTS
The molecular weight of the impurity was 14 less than that of caderofloxacin. It means the impurity was a CH2-group less than caderoflixacin. The tR, UV and MS of DMCA were the same as those of the impurity in caderofloxacin.


CONCLUSIONS
Based on the tR (HPLC), UV and MS, the impurity of caderofloxacin is confirmed as DMCA.
Ma
Ren-ling
RL
Center for Instrumental Analysis, China Pharmaceutical University, Nanjing 210009, China. marenling@sohu.com
Zhou
Hong-hua
HH
Liu
Rong
R
Wang
Er-hua
EH
Sheng
Long-sheng
LS
D000890:Anti-Infective Agents / Q000737:chemistry*; D002264:Carboxylic Acids / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004340:Drug Contamination; D024841:Fluoroquinolones / Q000737:chemistry*; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry*; D011804:Quinolines / Q000032:analysis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
C489705:1-cyclopropyl-8-(difluoromethoxy)-6-fluoro-1, 4-dihydro-7-(1-piperazinyl)-4-oxo-3-quinoline carboxylic acid; D000890:Anti-Infective Agents; D002264:Carboxylic Acids; D024841:Fluoroquinolones; D010879:Piperazines; D011804:Quinolines; C097449:CS 940