Simultaneous Determination of Some 5-Nitroimidazole Derivatives and Ciprofloxacin by High Performance Liquid Chromatography

  Objective: An isocratic high performance liquid chromatographic method for simultaneous determination of Metronidazole, Tinidazole and Ciprofloxacin was developed. Method: Separation was achieved with a C18 (250x4.6 mm, 5 μm) column. Optimal chromatographic conditions were: mobile phase consisting of acetonitrile: 0.3% o-phosphoric acid modified with 0.1% triethylamine (20:80 v/v) at a flow rate of 0.7 mL min-1, at 30°C and wavelength of 300 nm. Results: The retention times were 4.92 min for Metronidazole, 8.78 min for Tinidazole and 9.76 min for Ciprofloxacin. The responses were linear (R2 = 0.9999) in the range of 12.5 – 100 μg mL-1. The limits of detection were 0.012 µg mL-1 for Metronidazole and Tinidazole and 0.04 µg mL-1 for Ciprofloxacin. The limits of quantification were 0.125 µg mL-1 for Metronidazole and Tinidazole and 0.4 µg mL-1 for Ciprofloxacin. The recovery (%) was within the range of 99.57 – 100.3% for all analytes. Conclusion: The method developed can successfully be used for routine analysis and quality control of Metronidazole, Tinidazole and Ciprofloxacin.