Xác định đồng thời các chất sildenafil và tadalafil trong các loại thuốc thảo dược bằng phương pháp HPLC

The HPLC method for the simultaneous determination of 2 PDE-5 (sildenafil and tadalafil) in herbal medicines was validated. Using acetonitrile and water as the mobile phase, Gemini C18 (250 x 4.6 nm, 5 um) column, UV detection at 285 nm and flow at 1 ml/min, the PDE-5 were separated satisfactorily within 6 minutes. The quantitation limits of sildenafil citrate and tadalafif were about 0.2 ug/ml and 0.3 ug/ml, respectively. The calibration curve of each PDE-5 had a correlation coefficient close to 1. The precisions were aIl less than 2 percent. The recovery rates of extraction were 92-100 percent for aIl PDE-5. This method can be used to detemine sildenafil citrate and tadalafil simultaneously in herbal medicines.