HPLC Determination of 3 Contraband Drugs(Tadalafil,Sildenafil and Vardenafil) in Health-care Foodstuffs

HPLC was applied to the determination of 3 contraband drugs,i.e.,tadalafil,sildenafil and vardenafil,in health-care foodstuffs.Prodigy 5 μ ODS 3 column(250 mm×4.6 mm) was used as stationary phase,and a mixture of acetonitrile and 0.05 mol·L-1 triethylamine solution,mixed in the ratio of 40 to 60,was used as mobile phase,with a flow-rate of 1.0 mL·min-1.UV-detection at 290 nm with diode array detector(DAD) was adopted in the determination.Qualitative analysis was performed on the base of retention time and with reference to the standard spectra.Linear relationships between values of peak area and concentration of all the 3 drugs were found in the range of 0.5-100.0 mg·L-1.Detection limits(S/N=3) found for tadalafil and sildenafil were 0.3 mg·L-1,and for vardenafil was 0.4 mg·L-1.Precision and recovery were tested on known samples,and values of RSD′s(n=6) found were in the range of 1.5%-2.0% and values of recovery obtained were in the range from 95.8% to 107.0%.