The effect of N-alkyl chain length of stereochemistry on the absorption, metabolism and during excretion of N-alkylamphetamines in man

Urinary excretion in man, of the unchanged drug and metabolite amphetamine, has been investigated after the (+)- and (-)-isomers of methyl-, ethyl-, n-propyl- and n-butyl- amphetamine had been taken by mouth under acidic urinary pH. The total metabolism of (+)-methyl-, ethyl-, and n-propyl-amphetamine was greater than that of the corresponding (-)-isomers but there was no difference in the total metabolism of the (+)- and (-)-n-butylamphetamine. A direct correlation was obtained for the (+)-but not the (-)-isomers between the partition coefficient of the compounds in an n-heptane/aqueous system, their buccal absorption and the total metabolism. The (+)-isomers of methyl- and ethyl-amphetamine were N-dealkylated more than their (-)-enantiomorphs but (-)-n-propylamphetamine was N-dealkylated more than the (+)-isomer.