Intra-arterial administration of hexobarbital enantiomers to the rat: disposition and estimation of apparent extraction ratio
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The enantiomers of hexobarbital, designated asS(+)-HB andR(−)-HB, were administered intra-arterially to rats in a dose of 25 mg· kg−1. Blood pharmacokinetics of the parent compound and two metabolites as well as urinary excretion of three major metabolites were studied. Using previously obtained data following oral administration ofS(+)-HB andR(−)-HB two different methods for calculation of the hepatic extraction ratio (E) were compared. The metabolite profile in the urine after intra-arterial administration was not basically different from corresponding data on oral administration. The clearance of low-dose, intra-arterially administeredS(+)-HB is useful as an indicator of hepatic blood flow in the rat.
Key wordsBlood flow, hepatic Clearance Enantiomers Extraction ratio Hexobarbital Metabolism Pharmacokinetics
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