Determinaton of sildenafil citrate and related substances in the commercial products and tablet dosage form using HPLC

This study aimed at developing and validating an HPLC method for the assay of sildenafil citrate and its related substances that might coexist in the drug commercial products and in tablets' formulation as impurities that ori ginate from synthesis processes or degradation. A chromatographic system co mprising a mu Bondapak C-18 (10 mum) column, a mobile phase of ammonium ace tate (pH 7.0, 0.2 M)-acetonitrile (1:1, v/v), a flow rate of 1 ml/min and a UV detector set at 240 nm has shown good chromatographic separation for si ldenfil and the other related substances. The degree of linearity of the ca libration curves, the percent recoveries of sildenafil and related substanc es, the limit of detection, LOD, and limit of quantitation, LOQ for the HPL C method have been determined. The HPLC method under study was found to be specific, precise, accurate, reproducible indicating stability and robust. (C) 2001 Elsevier Science B.V. All rights reserved.