Application of HPLC for detection of sildenafil/tadalafil in marketed honey in Oman

Honey adulteration allegedly with phosphodiesterase-5 (PDE-5) inhibitors including sildenafil, and tadalafil is a common and dangerous practice. This study aimed to develop a procedure to detect the presence of common adulterants namely sildenafil and tadalafil using RP-HPLC. Seven commercial honey samples of local and international origin were collected from supermarkets and honey sellers. Both the adulterants in honey samples were identified and quantified with the help of an HPLC technique. Chromatographic separation was done in RP-HPLC mode using buffer: methanol: acetonitrile (5.8: 2.5: 1.7) mobile phase and diode array as a detector. The buffer used was 0.05 M Triethylamine orthophosphate pH (3.0). The results showed that four honey samples (HAD1, HAD5, HAD6, and HAD7) were adulterated with sildenafil, and among them, HAD5 contained the maximum amount of sildenafil as 22.65 mg/g of the honey sample. However, only 2 honey samples HAD4 and HAD6 were found to be adulterated with tadalafil (1.248 and 0.7 mg/g) of the tested honey sample. The result of this study warrants rigorous quality control of the commercially available honey products in Oman by the authorities. The consumption of adulterated honey samples may impact the health of consumers hence further detailed studies must be carried out to confirm the findings of the current study and novel analytical methods be developed to detect the level of other possible adulterants in this valuable product.