On ups and downs by analysis of profen drugs. A mini review

Summary

Drug analysis is among the most sensitive areas of chemical analysis, simply because of its relevance to human health. Profens make the most important group of nonsteroidal anti-inflammatory drugs (NSAIDs), and in many countries some of them are freely sold over the counter. The in vitro liquid chromatographic analysis of profen drugs faces certain not commonly recognized yet acute and often impassable problems, due to the specific physicochemical properties of these compounds. In this mini review, we share our experience on the practical failures with the enantioseparation of profen drugs both by means of chiral planar and column chromatography. By use of such analytical techniques as polarimetry, ¹H and ¹³C NMR spectroscopy, and mass spectrometry, we point out objectively the reasons that make liquid chromatographic enantioseparation of profens an almost impossible task. These compounds have an inherent ability (both in aqueous and nonaqueous solutions) to undergo oscillatory chiral conversion and oscillatory condensation, combined with a highly pronounced gelating ability. In our view, the oscillatory chiral conversion of profens questions the credibility of widespread claims on the superiority of the curative potential with the (+)-profens over that of the respective (−)-antimers (although the rightfulness of such claims cannot be dismissed, as the in vivo and in vitro behavior of many drugs are known to sometimes fundamentally differ). Moreover, it seems highly probable that, due to their highly pronounced gelating property, profen drugs can easily clog the blood vessels and thereby jeopardize living organisms.