Development of a Stability-indicating UV spectrophotometric method by absorption ratio method for the estimation of Atorvastatin calcium (ATC) and Fenofibrate (FEN) in tablet dosages form. In absorption ratio method absorbance measurement of sample at 262nm (isoabsorptive point, λ1) and 287nm, λ2. The absorbance ratio method was developed using methanol as solvent. The linearity of the proposed method was investigated in the range of 6- 16 μg/ml and 2-12 μg/ml for ATC and FEN respectively. Calibration curves show a linear relationship between the absorbance and concentration. The line equation for ATC y = 0.041x + 0.043 with r2 of 0.999 and for Fenofibrate y = 0.054x -0.003 with r2 of 0.999 was obtained. Validation was performed as ICH guidelines for Linearity, accuracy, precision, LOD and LOQ. The LOD-0.2695 μg/ml, 0.0222 μg/ml for ATC and FEN and the LOQ-0.8780 μg/ml, 0.222 μg/ml for ATC and FEN respectively. The proposed method may be suitable for the analysis of ATC and FEN in tablet formulation for quality control purpose. The stability studies of ATC and FEN were conducted and the degradation characteristics were found to be much more prominent in acid hydrolysis in FEN and alkaline hydrolysis in ATC.
