Isocratic RP-HPLC Method for detection of Sildenafil in some Marketed Dietary Supplements

Abstract

Due to the widespread use of sildenafil, the market is full of different counterfeited preparations that contain either an unknown amount of sildenafil or mixed with one or more different varieties of unknown substances. These fake preparations are usually harmful to users. So, it is always necessary to develop specific as well as sensitive analytical procedures to detect sildenafil in such preparations. HPLC that equipped with modern sensitive detectors such as diode array detector (DAD) can play a great role in solving such problems. In this work, a new HPLC method was established for the detection of sildenafil in some marketed dietary supplements. Thermo scientific ODS HYPERSIL column (250 x 4.6 mm, 5µm) was used. The mobile phase was composed of methanol and potassium di-hydrogen phosphate buffer 0.05M (pH 3.5) at a ratio of 70:30 (v/v). Triethylamine (0.3%) was added to the mobile phase. The flow rate was 1mL/min. Detection was performed at 290 nm using a diode array detector. The method showed good linearity (5.0-80.0 µg/mL). The retention time was 5.3 min. The validation parameters were evaluated as per ICH guidelines. The findings given by the developed method were compared statistically to those achieved by a reported one. There was a good statistical agreement. The developed method is considered a sensitive and specific analytical method for the detection of sildenafil counterfeited dietary supplements.