Development of a Robust RP-HPLC Method for the Analysis of Ofloxacin and Nitazoxanide in Fixed-Dose Combination Products

A new method was established for simultaneous estimation of Ofloxacin and Nitazoxanide by RP-HPLC method.  The chromatographic conditions were successfully developed for the separation of Ofloxacin and Nitazoxanide by using Xterra C18 5µm (4.6*250mm) column, flow rate was 1ml/min, mobile phase ratio was Phosphate buffer (0.05M) pH 4.6: ACN (55:45%v/v) (pH was adjusted with orthophosphoric acid), detection wavelength was 255nm. The instrument used was Shimadzu, model No. SPD-20MA LC+20AD, Software- LC-20 Solution. The retention times were found to be 2.399mins and 3.907mins. The % purity of Ofloxacin and Nitazoxanide was found to be 100.7% and 101.4% respectively. The system suitability parameters for Ofloxacin and Nitazoxanide such as theoretical plates and tailing factors were found to be 1.3, 5117.5and 1.4, 3877.3 the resolution was found to be 5.31. In compliance with ICH criteria, the analytical procedure was verified (ICH, Q2 (R1)) 4. According to the linearity investigation, the concentration ranges of ofloxacin and nitazoxanide were 20μg–100μg and 10μg–50μg. The correlation coefficient (r2) was 0.999 and 0.999, and the percentage mean recovery was 100% and 100.5%. The repeatability RSD was between 0.2 and 0.4 percent. For intermediate precision, the corresponding RSDs were 0.5 and 0.1