ABSTRACT
Aspartame is the methyl ester of the dipeptide 1-aspartyl-l -phenylalanine. In considering the metabolism of this compound, it was expected that extensive degradation of the compound would occur in the gastrointestinal tract during the absorption process. The excretion of label into the urine and feces was similar after administration of either compound. The nature of the plasma radioactivity present after aspartame administration was investigated by passing the plasma through ultrafiltration membrane cones. These membranes retain molecules with molecular weights greater than 50,000 and have essentially no retention for molecules with molecular weights less than 5000. The presence of the aspartame molecule itself has not been demonstrated in the systemic circulation after its oral administration to experimental animals. In conclusion, studies conducted in a number of animal species indicate that aspartame is rapidly and extensively metabolized to its constituent amino acids and methanol.
