ABSTRACT
Objective:To establish a method for the determination of related substances in enoxacin gluconate injection by HPLC with gradient elution. Methods:HPLC was performed on a DiamonsilTM C18 column (250 mm × 4. 6 mm, 5 μm), the mobile phase A was 0. 025 mol·L-1 phosphonic acid solution (adjusting pH to 3. 0 with triethylamine)-methanol- acetonitrile (80∶10∶10) and the phase B was 0. 025 mol·L-1 phosphonic acid solution (adjusting pH to 3. 0 with triethylamine)-methanol-acetonitrile (350∶325∶325) with gradient elution at a flow rate of 1. 1 ml·min-1 , the detection wavelength was 269 nm and 284 nm, the injection volume was 20μl, and the column temperature was 40℃. Results:Under the HPLC conditions, the samples had good stability and separation. The calibration curve was linear within the concentration range of 19. 80 ng·ml-1-19. 80 μg·ml-1(r=0. 999 9) for 5-hydroxymethylfur-fural with the detection limit of 0. 18ng, and the average recovery was 99. 68% with RSD of 0. 12% (n=9). Conclusion:The method is accurate, sensitive, specific and reproducible, and can be used in the determination of related substances in enoxacin gluconate in-jection.
