Detection by gas chromatography-mass spectrometry of adulterated food supplements

The number of herbal food supplements on the Romanian market is continuously growing, with about 1500 new products every year, out of which approximately 15 products are aimed to enhance sexual performance. Phosphodiesterase type 5 (PDE-5) inhibitors such as sildenafil (Viagra (R)), tadalafil (Cialis (R)), vardenafil (Levitra (R)) and most recently avanafil (Stendra (TM)) are authorized drugs used in the treatment of erectile dysfunction. Certain herbal food supplements which claim to enhance the sexual performance have been found to be adulterated with these drugs. Our study aims to develop an useful method of gas chromatography-mass spectrometry (GC-MS) for the efficient screening of herbal food supplements supposed to be adulterated with sildenafil, tadalafil, and vardenafil. The identification of pharmacological active principles was done by detection of specific molecular ions for each compound: sildenafil (m/z 99, 404); tadalafil (389, 262) and vardenafil (113, 448). Sildenafil, tadalafil and vardenafil were successfully identified by GC-MS in different herbal food supplements. The results of this study show that six herbal food supplements were adulterated with PDE-5 inhibitors, which means 23% of the total 26 analyzed products.