Validated stability indicating liquid chromatographic method for quantification of ciprofloxacin HCL, its releated substance and tinidazole in tablet dosage form

Objective: A simple stability-indicating RP-HPLC method was developed for ciprofloxacin HCl, its analog ethylenediamine (EDA) and tinidazole. Methods: In the proposed gradient method mobile phase-A (potassium dihydrogen phosphate buffer, pH 4.5) and mobile phase-B (buffer and acetonitrile in 50:50 v/v) were pumped through HPLC Waters system equipped with Empower 2 software, separation was achieved on X-terra C18 column (4.5 x 150 mm ID, 5μm particle size) with a flow rate of 1mL/min and eluents were detected at 278 nm for ciprofloxacin HCl, it's analog EDA and 317 nm for tinidazole using PDA detector. The retention times were found to be 21.98, 18.56 and 11.02 for ciprofloxacin, EDA and tinidazole respectively. The developed method was also validated for linearity, accuracy, precision, specificity and robustness as per ICH guidelines. Results: The linearity was found in the range of LOQ-200% and shows a correlation coefficient of 0.999 for all three substances. The LOQ for ciprofloxacin HCl, tinidazole and EDA was found to be 0.105,0.153 and 0.119 μg/mL respectively. Degradation was observed for ciprofloxacin and tinidazole during stress conditions and their peaks were well separated from the degradation product peaks, the resolution was found to be more than 2.0. Conclusion: Hence the proposed method was a good approach for obtaining reliable results and found to be suitable for the routine analysis of ciprofloxacin HCl, tinidazole and related substance of ciprofloxacin HCl (EDA)