N-Descarboxymethyl-N-carboxyethyl Lacosamide-D3 is a labelled analogue of N-Descarboxymethyl-N-carboxyethyl Lacosamide (D289390). N-Descarboxymethyl-N-carboxyethyl Lacosamide is an impurity of Lacosamide (L098500), an anticonvulsant drug that enhances sodium channel slow inactivation, and is used to treat patients with epilepsy.