Abstract
The present manuscript describes the development of a simple, economical and LC-MS compatible stability indicating high performance liquid chromatographic (HPLC) method for the simultaneous analysis of ofloxacin (OFL) and tinidazole (TNZ) under different stresss conditons as specified by ICH. For the analysis, an isocratic method was chosen which used Phenomenex (250 x 4.6mm, 5μm particle size) ODS column and a SPD 20 A UV detector set at 298 nm. The mobile phase is a combination of organic phase and aqueous phase, where the former is a mixture of methanol and acetonitrile in the ratio of 3 : 7 and the latter is 0.1% trifluoroacetic acid solution (pH adjusted to 3.5 with dil ammonia solution). The ratio of aqueous and organic phase was 80 : 20, at a flow rate of 1.5 mL min-1.The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.9998 for OFL in the linearity range of 10 – 60 μg mL-1 and r2 = 0.9996 for TNZ and the linearity range is 15 – 90 μg mL-1. The assay results were found tobe in the range of 98.35 – 100.71% and 99.81-101.35% respectively for OFL and TNZ.The recovery level of OFL and TNZ was found to be in the range of 97.57–104.37% for the two formulations analysed and the %RSD was found to be < 2.0%. The stress degradation studies were performed using acid, alkali, water, hydrogen peroxide, uv light and heat. Since there is no coelution of the degradation products’ peaks with the drug peaks, it can be employed as a stability indicating method.Further the structure of the degradants can be studied by LC-MS,as the optimised mobile phase is LC-MS compatible.