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)

Development of Dissolution Test Method for Drotaverine Hydrochloride/Mefenamic Acid Combination Using Derivative Spectrophotometry

Purpose: To develop and validate a dissolution test method for tablets containing 80 mg of drotaverine hydrochloride (DRT) and 250 mg of mefenamic acid (MEF). Methods: Sink conditions, drug stability and specificity in different dissolution media were tested to optimize a dissolution test method using a USP paddle type dissolution test apparatus set at a speed of 50 rpm. The dissolution medium consisted of 900 ml of phosphate buffer (pH 6.8) containing 0.25% w/v cetrimide at 37 ± 0.5 oC and 45 min time-point. To determine both drugs simultaneously, a first derivative UV spectrophotometric method was developed and validated. Drug release was analyzed by first derivative UV method at 253.8 nm and 304 nm for DRT and MEF respectively. The dissolution method was validated as per ICH guidelines. Results: The two brands each showed 98% of drug release for both drugs when the developed dissolution method was used. The regression plot was linear in the concentration range 4 - 24 µg/mL for each of the drugs and regression coefficient (r2) was greater than 0.999 for each drug. Relative standard deviation (% RSD) for precision and accuracy of proposed method was < 2. Conclusion: The proposed dissolution method is simple, cost-effective, precise, accurate and specific. It can be successfully employed in routine quality control of DRT and MEF combination tablets