Stereoselectivity in absorption of Trans tramadol in rat intestine

AimTo investigate the stereoselectivity in absorption of Trans tramadol (Trans T) in rat intestine. MethodsThe duodenum, jejunum and ileum were separately perfusated in situ with Trans T dissolved in Krebs-Ringer buffer. Trans T enantiomers in the perfusate were analyzed with a high performance capillary electrophoresis (HPCE) method. ResultsThe absorbed fractions of Trans T enantiomers were similar among the different segments of the rat intestine. The absorbed fraction of (+)-Trans T was lower than that of (-)-Trans T when the concentration of Trans T was not higher than 40 μmol·L^-1. As the concentration of Trans T increased, the absorbed fractions of Trans T enantiomers were reduced and the difference in absorbed fractions between Trans T enantiomers became not significant. ConclusionTrans T enantiomers can be absorbed in different parts of the rat intestine. The intestinal absorption of Trans T was stereoselective, (-)-Trans T being preferentially absorbed.