HPTLC determination of sildenafil in pharmaceutical products and aphrodisiac herbal preparations

A high-performance thin-layer chromatographic (HPTLC) method has been established for determination of sildenafil citrate in commercial products. The compounds were separated on silica gel, with CHCl₃-MeOH-diethylamine, 90 + 10 + 1 (v/v), as mobile phase, and the analyte spots were quantified densitometrically at λ = 305 nm. Recovery of sildenafil citrate was 100.6 and 98.2%, for pure and spiked samples, respectively. Method precision and specificity were also validated. The method was used for determination of sildenafil in four pharmaceutical products and three aphrodisiac herbal preparations which were claimed to be totally natural. Levels of sildenafil in the pharmaceutical products ranged from 49.7 to 50.5 mg per tablet. Sildenafil was also detected in one herbal preparation at a concentration of 85.0 mg per capsule.