Riluzole-13C,15N2 is intended for use as an internal standard for the quantification of riluzole by GC- or LC-MS. Riluzole is a benzothiazole derivative with anti-excitotoxic effects that acts by blocking the presynaptic release of glutamate, indirectly antagonizing glutamate receptors, and inactivating neuronal voltage-gated Na+ channels (ED50 = 2.3 μM). Riluzole suppresses glutamate-induced seizures in rats at an ED50 value of 3.2 mg/kg and displays neuroprotective effects in hypoxic animals at an ED50 value of 4 mg/kg. Formulations containing riluzole have been explored as therapeutics for slowing disease progression of amyotrophic lateral sclerosis.