DEVELOPMENT AND VALIDATION OF ASSAY METHOD FOR ESTIMATION OF ATORVASTATIN

UV-Vis spectrophotometric method is a well-established technique to assay bulk drug as well as formulation owing to its simplicity as well as time efficiency. This work is an aim to develop simple and sensitive method to assay atorvastatin calcium both in bulk as well as in tablet by UV spectrophotometric method. New UV- spectrophotometric assay was developed using phosphate buffer and methanol which is used as cosolvent. In this method the drug was dissolved in methanol and diluted with methanol and phosphate buffer (pH 7.2). Method validation parameters like linearity, accuracy, precision, robustness and specificity of the method was studied as per ICH recommendation. The same method was also applied to estimate the drug in tablet formulation. λmax of atorvastatin calcium was found to be 244 nm and hence all the UV absorbance was noted at 244 nm. Beer’s Law was obeyed (R2= 0.999) by this method at a concentration range of 1-10 μg/mL. This method was found to be accurate and % recovery was noted as satisfactory label. The percentage relative standard deviation value for all parameters was found to be less than 2%. The method was not influenced significantly by the change of wavelength, temperature and pH as evident from the robustness study. Moreover, specificity study suggested that the method was free from interference by excipients used in formulation. Hence it can be inferred that the developed method is precise, accurate, robust, and specific yet rapid and can be utilized for day-to-day estimation of atorvastatin calcium in bulk as well as in tablet formulation.