The urinary output of d- and l-amphetamine in man

Racemic amphetamine or methylamphetamine was administered to four human subjects, and the urine was collected in a total of fourteen experiments. The proportion of the optical isomers present in the urine was determined by gas chromatography of the diastereosiomers formed when a urine extract was reacted with trifluoroacetyl- l-prolyl chloride. After administration of racemic amphetamine the optical isomers were not excreted at the same rate. The ratio of the d-isomer to the l-isomer in the urine decreased from 0.99 during the first 12 hr to 0.46 at 48–60 hr. Although the total urinary excretion of amphetamine is pH-dependent, the differential excretion of the d- and l-isomers occurred whether the urine was acid or alkaline. Racemic methylamphetamine was metabolized to amphetamine and the main isomer excreted in the urine was d-amphetamine, whereas l-amphetamine was formed to a lesser extent.