[The Configuration of Tadalafil and Tadalafil Analogues Found in Dietary Supplements].

This study determined the configuration of the isomers of tadalafil, nortadalafil, and homotadalafil in dietary supplements. The products purchased over the Internet studied included a honey product and a tablet, which contained tadalafil, and a candy, which contained nortadalafil and homotadalafil. Each of the pharmaceutical ingredients isolated from the products was measured with circular dichroism (CD).As a result, the CD spectrum of each isolated pharmaceutical ingredient was found to align with the standard CD spectrum of the 6R,12aR isomer, confirmed that each isolated tadalafil or tadalafil analogue included in a 6R,12aR isomer. According to a report, among the stereoisomers of tadalafil, the 6R,12aR isomers have the most potent inhibitory activities of phosphodiesterase-type-5. From the report, the potential strength of the inhibitory activity of the 6R,12aR isomers of nortadalafil and homotadalafil was suggested. Therefore, it seemed that the 6R,12aR isomer often used in the product.

Characterization of a new illicit phosphodiesterase-type-5 inhibitor identified in the softgel shell of a dietary supplement.

A new sildenafil analog has been identified in the softgel shell of a dietary supplement. The compound was investigated by UV spectroscopy and high-resolution MS analysis, leading to the proposed structure 1-methyl-5-{5-[2-(4-methylpiperazin-1-yl)acetyl]-2-propoxyphenyl}-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one. A synthetic reference compound with the proposed structure was prepared, and the two sets of analytical data were compared, confirming the structure of the new compound. The compound was named propoxyphenyl noracetildenafil from its structure and similarity with the known compound.