[Stereoselectivity in biliary excretion of trans tramadol and trans O-demethyltramadol in rats].
OBJECTIVE
To investigate the stereoselectivity in biliary excretion of trans tramadol (trans T) and trans O-demethyltramadol (M1) in rats.


METHODS
After a single intravenous dose of trans T hydrochloride (10 mg.kg-1) or M1 (2.5 mg.kg-1) to rats, the bile was collected for 30 min, then, blood was obtained from the heart. The enantiomers of trans T, M1 and M1 conjugated with glucuronic acid (M1c) in the bile and plasma were analyzed by high performance capillary electrophoresis (HPCE).


RESULTS
After the rats were given trans T, the bile concentrations of (+)-trans T were higher than those of (-)-trans T, and the (+)/(-)-trans T ratios were lower compared with those in the plasma. After the rats were given M1, the bile concentrations of (+)-M1 were higher than those of (-)-M1, and the bile concentrations of (+)-M1c were lower than those of (-)-M1c. The glucuronidation rate of (+)-M1 was lower than that of (-)-M1 in the bile.


CONCLUSIONS
The biliary excretion of trans T and M1 was stereoselective, (+)-trans T and (-)-M1 being preferentially excreted.
D000701:Analgesics, Opioid / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D000818:Animals; D001646:Bile / Q000378:metabolism*; D005260:Female; D020723:Glucuronic Acid / Q000378:metabolism; D007275:Injections, Intravenous; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013237:Stereoisomerism; D014147:Tramadol / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*
D000701:Analgesics, Opioid; C080580:O-demethyltramadol; D014147:Tramadol; D020723:Glucuronic Acid