Metabolism and excretion of diethylpropion in man under acidic urine conditions

After oral administration, diethylpropion is rapidly and extensively metabolized in man by N-de-ethylation and stereoselective carbonyl reduction. The unchanged drug excreted in acidic urine represents about 2% of the dose, while the total metabolites determined account for some 85%. The excretion curves indicate that the probable contribution of the parent compound to the observed activity is small. The major metabolites, together representing about 70% of the dose, are N-ethylaminopropiophenone, (+)-N-diethylnorpseudoephedrine, (+)-N-ethylnorpseudoephedrine, (-)-norephedrine and (-)-norpseudoephedrine. The other stereoisomers of the three amino-alcohols, and aminopropiophenone, are present in minor amounts.