Simultaneous Determination of Dapoxetine and 4 PDE5 Inhibitors in Aphrodisiac Health-Care Products by RP-HPLC

A method for simultaneous determination of dapoxetine and 4 PDE5 inhibitors in aphrodisiac health-care products by RP-HPLC was proposed. The sample was dissolved in water and extracted with methanol. The extract (10 μL) was introduced and separated by using Inertsil ODS-SP chromatographic column as stationary phase and mixtures of 0.8% (φ) triethylamine-0.4% (φ) acetic acid,acetonitile and 0.02% (φ) H3PO4 solution with different mixing ratios as mobile phase in the gradient elution. UV-detection at 290 nm was adopted in the determination.Linear relationships between values of peak area and mass concentration of tadalafil was kept in the range of 1.25-25.0 mg·L-1 and for the other 4 compounds in the same range of 5.0-100 mg·L-1. Detection limits (3S/N) found were ranged from 0.05 to 0.2 mg·L-1. Values of recovery found by standard addition method were in the range of 94.1%-109%, with values of RSD′s (n=6) less than 1.0%.