Rapid RP-HPLC Method for Simultaneous Estimation of Sparfloxacin, Gatifloxacin, Metronidazole and Tinidazole

An isocratic RP-HPLC method had been developed for rapid simultaneous separation and determination of sparfloxacin, gatifloxacin, metronidazole and tinidazole in pure form or in presence of some impurities within 5 minutes. Separation was carried out on a Chromolith^® Performance RP-18e (100 x 4.6 mm) using a mobile phase of MeOH: 0.025M KH₂PO₄ adjusted to pH 3 using ortho -phosphoric acid (20:80, v/v) at ambient temperature. The flow rate was 4 ml/min and maximum absorption was measured at 290 nm. The standard curve was linear in the concentration range of 1–80 μg/mL for all drugs. The retention time of sparfloxacin, gatifloxacin, metronidazole and tinidazole was noted to be 4.3, 3, 1.8 and 1.2 minutes respectively, indicating shorter analysis time. The method was validated according to ICH guidelines. The proposed method was found to be accurate, reproducible, and consistent. It was successfully applied for the analysis of these drugs in marketed formulations and could be effectively used for the routine analysis of formulations containing any one of the above drugs, or a combination, without any alteration in the chromatographic conditions.