Determination 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 originate from synthesis processes or degradation. A chromatographic system comprising a microBondapak C(18) (10 microm) column, a mobile phase of ammonium acetate (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 sildenfil and the other related substances. The degree of linearity of the calibration curves, the percent recoveries of sildenafil and related substances, the limit of detection, LOD, and limit of quantitation, LOQ for the HPLC method have been determined. The HPLC method under study was found to be specific, precise, accurate, reproducible indicating stability and robust.