Analytical Method Development and Validation of Sildenafil Citrate by RP-HPLC

A simple, selective, accurate reverse phase - high Performance Liquid Chromatographic (RP-HPLC) method was developed and validated for the analysis of Sildenafil Citrate in pharmaceutical formulations. Chromatographic separation achieved isocratically on a C18 column [Use Symmetry C18, 250 X 4.6mm, 5? (P/N: WATO54275)] utilizing a mobile phase of Acetonitrile/Phosphate buffer (35:65, v/v) at a flow rate of 1.0ml/m with PDA detection at 230nm. The retention time was 6.74±0.05. The method is accurate (99.7-104.1%), precise (the relative standard deviations of intra and inter-day assay were 99.3% and 99.9% respectively) and linear within range 5-150μg/ml (R2=0.999) concentration and was successfully used in monitoring left over drug. The limit of detection and limit of quantification for Sildenafil Citrate drug was found to be 0.03μg/ml and 0.1μg/ml. The proposed method is applicable to stability studies and routine analysis of Sildenafil Citrate in pharmaceutical formulations.