Validation and stability indicating RP-HPLC method for the determination of sildenafil citrate in pharmaceutical formulations.

ABSTRACT

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 Inertsil C18, 5m , 150 mm x 4.6 mm] utilizing a mobile phase of acetonitrile/phosphate buffer (7030, v/v, pH 7.0) at a flow rate of 0.8 ml/m with UV detection at 228 nm. The retention time was 4.087. The method is accurate (99.15-101.85%), precise (intraday variation 0.13-1.56% and inter-day variation 0.30-1.60%) and linear within range 0.1- 30μg/ml (R2=0.999) concentration and was successfully used in monitoring left over drug. The detection limit of sildenafil citrate at a signal-to-noise ratio of 3 was 1.70ng/ml in formulations while quantification limit in drug was 5.40 ng/ml. The proposed method is applicable to stability studies and routine analysis of sildenafil citrate in pharmaceutical formulations.