Spectrum Characteristic of Typical Fluoroquinolone Antibiotics Under Different Acid-basic Conditions

Abstract:

The structural morphology and spectra characteristic of Ciprofloxacin (CIP) and Norfloxacin (NOR) was strongly affected by the pH.In strong acidic solutions,fluoroquinolone molecules exist as strong cation to achieve a weaker intensity.When the pH value increases to 3~4,fluoroquinolone molecule exist as zwitterions,which is the strongest fluorescence form to have maximum intensity;the maximum exciting-emission wavelength (λexλem)of CIP and NOR were 280＼459 nm and 281＼450 nm,respectively.Along with the increase in neutral pH value,fluoroquinolone molecules exist as weak anion,fluorescence spectrum and UV spectrum change,the intensity decreases;under basic condition,fluoroquinolone molecule exists in anion ion form,and fluorescence and UV intensity decreases with pH increasing,but spectrum remains essentially constant.

Key words:fluoroquinolone; fluorescence spectrum; ultraviolet spectrum; ciprofloxacin; norfloxacin