A Novel Stability Indicating RP-HPLC Method Development and Validation for Simultaneous Estimation of Silodosin and Tadalafil in its Synthetic Mixture

The objective of this research is to design and validate a reliable Stability-Indicating RP-HPLC method for the simultaneous determination of Silodosin and Tadalafil in a synthetic mixture. A RP-HPLC method was established using an Agilent Eclipse XDB C18 column (150 mm × 4.5 mm ID × 5 μm) as the stationary phase. The mobile phase consisted of 0.1% TEA and ACN in a 60:40 (v/v) ratio. Sample injection was conducted at a flow rate of 1.0 mL/min, with detection set at a wavelength of 278 nm. Linearity within the concentration ranges of 40–120 μg/mL for Silodosin and 25-75 μg/mL for Tadalafil, with correlation coefficients (r²) of 0.9997 and 0.9996, respectively. Precision studies confirmed method repeatability, as the percentage relative standard deviation (% RSD) remained below 2%. Robustness assessment also demonstrated % RSD values under 2%, indicating the method’s reliability despite minor variations in analytical conditions. Accuracy was validated through a recovery study, confirming the method’s suitability for precise quantitative analysis. Validation was performed in accordance with the International Conference on Harmonization (ICH) guidelines, demonstrating excellent precision, accuracy, linearity, specificity, sensitivity, and robustness.