Analysis of illicit dietary supplements sold in the Italian market: identification of a sildenafil thioderivative as adulterant using UPLC-TOF/MS and GC/MS.

Identification of pharmaceutical active ingredients sildenafil and tadalafil and the characterization of a dimethylated thio-derivative of sildenafil, called thioaildenafil or thiodimethylsildenafil, in illicit dietary supplements were described. A multi-residual ultra-performance liquid chromatography-time of flight mass spectrometry (UPLC-TOF/MS) method was developed to screen for the presence of the phosphodiesterase-5 (PDE-5) inhibitors sildenafil, tadalafil, and vardenafil and their analogues thioaildenafil and thiohomosildenafil in powders and pharmaceutical dosage forms. The study was developed in connection with an operation supervised by the Italian Medicines Agency (A.I.F.A.), aimed to monitor dietary supplements in the Italian market. In two of the eleven specimens under investigation, high-resolution mass spectrometry (HR-MS) allowed the identification of the PDE-5 inhibitors sildenafil and tadalafil, while another specimen proved to contain a unapproved dimethylated thioderivative of sildenafil, thioaildenafil or thiodimethylsildenafil, identified for the first time in Italy as adulterant in food supplements.

Melatonin enhances the in vitro action of cytochalasin B on globular resistance and osmotic fragility of erythrocytes.

BACKGROUND: Some researches have shown that melatonin (MLT) has effects on the erythrocyte deformability and on the osmotic fragility which, currently, seem to be heterogeneous and fragmentary. OBJECTIVE: This work wished to evaluate in vitro the possible modifying action of MLT at pharmaceutical doses on the osmotic fragility of rat blood samples treated with cytochalasin B (CB). The variation of the lactate dehydrogenase (LDH) levels have been measured because LDH is an enzyme which is considered an important marker of hemolysis. Working in a strongly reducing environment has been necessary in order to avoid possible antioxidant actions of MLT, measuring the plasma levels of malondialdehyde and total phospholipids in order to highlight possible MLT actions which are not related to its recognized antioxidant properties. RESULTS: The data show a possible MLT action which strengthens the CB action on the osmotic fragility and on the membrane deformability of the erythrocytes. CONCLUSIONS: Under the adopted working conditions, a direct relation of MLT with the biochemical dynamics of the cytoskeleton-mediated processes can be suggested. Further studies will be needed to clarify the mechanisms and the extent of the observed phenomena.