Validated LC method for sildenafil citrate related substances and its potential oxidative degradation productAuthor(s): A.Nageswari, P.Surya Prakash Rao, B.Gowri Sankar Rao, B.Satyanarayana, M.Saravanan, V.Ranga Reddy, Mukkanti
A novel stability indicating LC method has been developed and validated for the simultaneous quantitative determination of Sildenafil citrate, its related substances and degradation products. The drug substance was subjected to stress conditions of hydrolysis (acid, base and water hydrolysis), oxidation, photolysis and thermal conditions to assess the degradation. Considerable degradation was observed under oxidative stress conditions. The resulting degradation product under oxidative stress condition was identified by LC-MS. This degradation product was isolated by preparative HPLC and its structure was further confirmed by spectroscopic techniques namely Mass, NMR and FTIR. The stressed samples were assayed against a qualified reference standard and the mass balance was found 99.6%. The developed method is applicable for determination of Assay, related substances and degradation products of Sildenafil citrate. The developed method was validated for linearity, accuracy, precision, range, specificity, ruggedness and robustness by considering Sildenafil citrate, its related substances and degradation products.