Kinetics, salivary excretion of amphetamine isomers, and effect of urinary pH

Abstract

Amphetamine was administered to healthy subjects as the racemic mixture and as (+)‐and (−)‐isomers under conditions of urine acidification and alkalinization. Plasma and saliva concentration of each isomer was measured and the kinetics of the individual isomers were determined. (+)‐amphetamine was eliminated more rapidly than the (−)‐isomer. The difference in half‐life between isomers was maximal under basic urinary pH conditions. Saliva amphetamine levels were higher than plasma levels and in the postabsorptive phase were predictably proportional to plasma drug levels.