Differences between gastric antiulcer effects of trapencaine enantiomers

The spatial arrangement of single stereoisomers may influence pharmacodynamic, pharmacokinetic and toxicological properties of a drug. Trapencaine (I. N. N.), (±)-trans-2-(pyrrolidin-1-yl)cyclohexyles-ter of 3-(n)-pentyloxycarbanilic acid, was developed as an antiulcer drug with gastroprotective, local anaesthetic and spasmolytic effects. Limited information is available about the potential pharmacodynamic differences of the enantiomers of trapencaine. Therefore, the enantiomers of (±)-trans- or cis-2-(pyrrolidin-1-yl)cyclohexylester of 3-(n)-pentyloxy carbanilic acid were synthesised and tested on models of acute gastric damage induced by indomethacin and/or ethanol. A difference was found between their antiulcer effect, with the (+)-trans-enantiomer being the most effective and the (–)-cis-enantiomer the least effective in the models used.