Rapid RP-HPLC Method for Simultaneous Estimation of Norfloxacin and Tinidazole in Tablet Dosage Form

An isocratic RP-HPLC method had been developed for rapid simultaneous separation and determination of norfloxacin and tinidazole in tablet dosage form and also in presence of some impurities within 2 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 both drugs. The retention time of tinidazole and norfloxacin was noted to be 1.2, and 1.6 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 which is useful for the routine determination of norfloxacin and tinidazole bulk drug and in its pharmaceutical dosage form.