Detection of sildenafil in selected traditional medicines

Abstract

Herbal remedies and traditional medicines have been widely consumed due to belief that natural-based products are safer and healthier as compared with synthetic ingredients products. However, one of the major concerns related to the safety of these products is their adulteration as undeclared synthetic chemicals used in order to enhance the claims stated on label. It was reported that the presence of sildenafil was mainly found in traditional medicines which is legally prohibited because of the harmful side effect. In addition, customers nowadays can have easily access to obtain the medicines since the widespread use of online purchasing system. Therefore, this research was embarked to determine the presence of sildenafil in different traditional medicines with simple, efficient and sensitive method. Eleven traditional medicines were obtained through online system. Samples were extracted with chloroform using Liquid-Liquid Extraction (LLE) technique and were analyzed using Alpha P-Fourier Transfer Infrared Spectrometer with Diamond Attenuated Total Reflectance (ATR) for identification. Separation and further analysis was done using High Performance Liquid Chromatography (HPLC) method. The residue obtained from extraction process were dissolved with diluents, acetonitrile:water (50:50). The compounds were separated by reverse phase chromatography with mobile phase H2O:ACN (60:40) + 1 mL Trifluoroacetic acid (TFA) and detected by Diode Array Detector (DAD) at UV wavelength of 285 nm with flow rate 1 mL/min. The calibration curve show good linearity with r2=0.999 over linear dynamic range of 0.00 µg/mL to 30 µg/mL with limit of detection (LOD) is 0.85 ppm, limit of quantification (LOQ) is 2.83 ppm and %RSD is 2.57%. Results found 3 out of 11 samples analyzed were positive detected with sildenafil.