A novel reverse phase high performance liquid chromatographic(RP-HPLC) method has been developed and validated for simultaneous estimation of Sildenafil Citrate Dapoxetine Hydrochloride in pure and marketed formulations. Separation was carried out using column Hypersil BDS C18 (100mm x 4.6mm x 5μ particle size) in isocratic mode using mobile phase composition of 0.1% orthophosphoric acid: Acetonitrile in the ratio of 50:50 and PH adjusted to 5.0±0.1 with sodium hydroxide of the flow rate was 1.0 ml/min and the effluent was monitored at 287nm. The retenion time of Sildenafil Citrate was found to be 3.14 min and for DapoxetineHydrochrloride 4 min. The method was linear from the concentration of 12.5 -62.5 μg/ml and 7.5-37.5 μg/ml for the estimation of Sildenafil Citrate and Dapoxetine Hydrochloride. The LOD and LOQ were found to be 0.824μg/ml and 2.499μg/ml for Sildenafil Citrate and of Dapoxetine Hydrochloride were found to be 0.90 μg/ml and 2.739 μg/ml. They undergo degradation in acids, alkalies, thermal and peroxides. The method was validated according to the guidelines of international conference on harmonization (ICH) and was successfully applied in the estimation and commercial formulations.
