Method Development and Validation of Stability Indicating Methods for Assay of Tadalafil and Sildenafil Citrate by Hplc

The simple, reliable and reproducible HPLC methods were developed for the analysis of Tadalafil and Sildednafil citrate(API). The column used was YMC-Pack ODS AQ (150 mm x 4.6 mm,i.d.).The mobile phase used was phosphate buffer (10mM,pH 3.0) acetonitrile gradient run at the flow rate of 1mL/min with UV (PDA) detector at 220nm at ambient temperature. Extraction of Tadalafil and Sildenafil citrate from tablet was carried out using methanol. Linearity was observed in the range from 50 to 150μg/ml for tadalafil with a correlation coefficient (R) 0.99 and 10ng/ml as the limit of detection. The values of linearity range, correlation coefficient(R) and limit of detection were 50 to 150μg/ml, 0.99 and 20ng/ml respectively for sildenafil. Parameters of validation prove the precision and stability of the method and it’s applicability for the Assay of tadalafil and sildenafil citrate. The method is suitable for routine analysis of the drug.