ABSTRACT
<p><b>AIM</b>To investigate the stereoselectivity in absorption of trans tramadol (trans T) in rat intestine.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>The 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 mumol.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.</p><p><b>CONCLUSION</b>Trans 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.</p>