6% (inter-day precision) and 0.5%, 0.6% (intra-day precision) for IB and FM, respectively. This is confirming good precision of the method. The results are summarized in Table 3. Table 3 Results from determination of intermediate precision Accuracy The accuracy of an analytical method expresses the nearness between the reference value and found value. The accuracy of the method was evaluated in triplicate at three concentration levels, i.e. 50%, 100%, and 150% of target test concentration (52 ��g mL�C1 of FM, 1600& ��g mL�C1) of IBU in tablets. The results obtained are shown in Table 4. Table 4 Results from study of accuracy for drug product Limit of detection (LOD) and limit of quantification (LOQ) The LOD and LOQ were estimated at a signal-to-noise ratio of 3:1 and 10:1, respectively, by injecting a series of dilute solutions with known concentration. The limit of detection of IB and FM was 1.72 and 0.54 ��g mL-1, respectively. The limit of quantification of IB and FM was 5.73 and 1.64 ��g mL-1, respectively. Linearity The calibration curves plotted for FM and IB were linear over the concentration range of 50-160 ��g/ml for FM, 1600-4800 ��g/ml for IB. Peak areas were plotted against concentrations, and linearity regression analysis performed for the resultant curve. The correlation coefficient values of FM and IB are 1.000 and 0.999. Robustness The robustness of a method is its capacity to remain unaffected by small changes in conditions. To determine the robustness of the method, the experimental conditions were deliberately altered and system suitability parameters like relative standard deviation for replicate injections of IB and FM peaks and the USP resolution factor between IB and FM peaks were evaluated. The mobile phase flow rate was 0.3 mL min�C1. This was changed by 0.03 units to 0.27 and 0.33 mL min�C1, and the effect was studied. Similarly, the effect of column temperature was studied at 20 and 30 ��C instead of 25 ��C. The effect of mobile phase organic composition was studied by �� 10%. The effect of mobile phase pH was studied by �� 0.2 units. In all the deliberate varied chromatographic conditions (flow rate, column temperature, and composition of organic solvent), no significant difference observed in system suitability [Table 5]. Table 5 Results from study of robustness CONCLUSION A novel UPLC method proves to be simple, linear, precise, accurate, robust, rugged, and specific. The total runtime was 4 min, within which two drugs and their degradation products were separated. The method was completely validated showing satisfactory data for all the method validation parameters tested. The developed method is stability-indicating and can be used for simultaneous quantitative determination of the drugs IB and FM in presence of degradation products in stability by the industry. The adopted UPLC method can also be useful for the assay estimation of IB tablets, FM tablets individually also.