Analytical method development and validation for the simultaneous estimation of candesartan and simvastatin by UV- spectrophotometry method

Efforts were made in the current work to create a method for the simultaneous estimation of Candesartan and Simvastatin by UV-spectrophotometry method employing simultaneous equation approach. In this approach ethanol was used as a solvent to check the solubility of both the drugs. At 200-400nm wavelengths, 16μg/mL prepared diluted stock solution each of both the drugs were scanned and estimated using methanol as blank. From the overlain spectra, by the observation of spectral characteristics of Candesartan and simvastatin were selected for simultaneous estimation. For simvastatin and candesartan 239nm as well as 262nm wavelength has been chosen respectively. As per ICH guidelines all analytical methods were validated. In this approach, the linearity value of both the drugs (Candesartan and Simvastatin) were found in the concentration range of 5-17.5 μg/mL and 3 – 10.5μg/ml respectively. The correlation coefficient (r2) value was obtained 0.999 for both the drugs. Candesartan and Simvastatin percentage recovery was found to be 99.26% and 97.48%. For intra and interday precision, percentage RSD value was found to be 0.99 and 1.7 (Intraday) as well as 1.0 and 1.78 (Interday). The intraday and interday relative standard deviation (RSD) values obtained by the proposed method are within 2% relative standard deviations. The LOD for candesartan and Simvastatin were found to be 0.258 μg/ml and 0.278μg/ml, and LOQ 0.784μg/ml and 0.84μg/ml respectively. Through the study of the candesartan and simvastatin solution in 0.1 NHCl using various glassware, the robustness of the established approach demonstrates a non-significant influence of the absorption level and the developed method's robustness was proven when the results were tested at various temperatures and when the results did not significantly alter when the analyst was switched.