Fast and semiquantitative screening for sildenafil in herbal over-the-counter formulations with atmospheric pressure solid analysis probe (ASAP) to prevent medicinal adulteration

Herbal medicines are commonly used in many countries all around the world. In Western countries they are now gaining more and more popularity, whereas in countries like China and India they have been entrenched for millenniums. Some of these perceived herbal medicines claim to help when suffering from erectile dysfunction. Nevertheless, many of these products are adulterated with PDE5 inhibitors like sildenafil or α-blockers. Patients who suffer from high blood pressure sometimes resort to herbal products, as they are not allowed to take sildenafil because of negative drug-drug interactions with nitrates (often utilized as treatment for coronary diseases). Products which are then adulterated with PDE5 inhibitors, can seriously harm patients. Therefore, this study reports the instant screening of alleged herbal products by employing atmospheric pressure solids analysis probe and high-resolution mass spectrometry to determine adulterants. Three out of 12 investigated products contained sildenafil in ranges from 0.5% to 18%. Multivariate analysis of ambient mass spectrometry measurements revealed encouraging outcomes for distinguishing non-sildenafil and sildenafil adulterated samples. Atmospheric pressure solids analysis probe is therefore a promising method for the rapid determination of sildenafil in herbal products with possible downstream semiquantitative analysis.