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Chiroptical and vibrational spectroscopic study of genuine and counterfeit medicines containing tadalafil
Author(s) -
Králík František,
Jirmásek Patrik,
Kuchař Martin,
Setnička Vladimír
Publication year - 2018
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.22828
Subject(s) - tadalafil , chemistry , counterfeit , conformational isomerism , circular dichroism , vibrational circular dichroism , ab initio , density functional theory , computational chemistry , crystallography , erectile dysfunction , organic chemistry , molecule , psychology , psychiatry , political science , law
The production and distribution of counterfeit pharmaceuticals present a serious problem worldwide. This is true especially in case of phosphodiesterase type 5 inhibitors for treating erectile dysfunction, where consumers often prefer buying them anonymously from unverified sources. In this study, genuine and counterfeit Cialis® 20 mg tablets were analyzed by electronic circular dichroism, vibrational circular dichroism, and infrared spectroscopy. The characteristic spectral patterns were identified by comparison with the spectra of tadalafil standard as an active pharmaceutical ingredient, and its presence was confirmed in all samples. The amount of tadalafil, however, was markedly lower in the case of counterfeit tablet as the observed band intensities were considerably lower. No other significant differences between the genuine and counterfeit tablets were revealed. Ab initio density functional theory calculations provided a detailed description of the stable conformers of tadalafil in a solution and enabled thorough interpretation of the experimental spectra.