Development of validated stability indicating assay method for simultaneous estimation of Diclofenac Sodium and Misoprostol in their combined dosage form

A Stability indicating Reverse-Phase liquid chromatographic method for the simultaneous estimation of DF and MP was developed. The chromatographic assay involves the use of Hi Q C18 W, 150 x 4.6mm, 5m column with a simple mobile phase composition of Acetonitrile and HPLC Grade water in the ratio of 70:30%v/v at a flow rate of 1mL/min with U.V detection at wavelength of 220 nm. The method showed good linearity in the concentration range of 50-100 ?g/mL for DF and 0.20-0.40 ?g/mL for MP. The proposed method was also successfully applied to 20 tablets of marketed formulation (Arthotec). The developed method was successfully validated as per the ICH guidelines for following parameters. Accuracy, precision, repeatability, ruggedness, robustness, system suitability tests, etc. The RSD for Intra-day and Inter-day precision was found to be 0.96-1.85, 1.02-1.83 For DF and 0.55-0.59, 0.59-0.63 for MP. The average percentage recoveries for DF were found to be 90.83, 99.74, 100.21 and for MP it was found to be 100.83, 98.94, 99.72. which was in good agreement with labeled amount of Pharmaceutical formulation. The stability indicating capacity was tested by accelerated degradation of marketed formulation in acidic (0.1 N HCl), basic (0.1 N NaOH), Neutral (water), Oxidative (3% H 2 O 2 ), Thermal (60 0 C), Sunlight exposure