Stability Indicating Rp-HPLC Method Development and Validation for Simultaneous Estimation of Silodosin & Tadalafil in Capsule Dosage Form

A simple, precise, accurate, economical and rapid stability-indicating reverse-phase high-performance liquid chromatographic (RP-HPLC) method has been developed and validated for the simultaneous estimation of Silodosin and Tadalafil in capsule dosage form. Chromatographic separation was achieved using a Aglilent zorbax C18 (250 mm x 4.6 mm x 5 µ) with a isocratic mobile phase consisting of acetate buffer (pH 3.7), acetonitrile and Trifluoracetic acid at a flow rate of 1 mL/min. Detection was carried out at 284 nm, with column temperature maintained at 25°C. Retention times were noted as 16.328 min for Silodosin and 11.255 min for Tadalafil respectively. Various analytical validation parameters, including specificity, linearity, LOD, LOQ, precision, accuracy, and robustness, were determined per ICH Q2 (R2) guidelines. Linearity was established over 80–240 μg/mL for Silodosin and 50–150 μg/mL for Tadalafil. The proposed method was successfully applied for the simultaneous estimation of both the drugs in commercial combined dosage form