FELBAMATE-D4

Felbamate-d₄ is intended for use as an internal standard for the quantification of felbamate by GC- or LC-MS. Felbamate is an inhibitor of NMDA receptors and a modulator of GABA_A receptors that also has broad-spectrum inhibitory activity against excitatory amino acid receptors. It binds to NMDA channels with dissociation constants of approximately 200, 110, and 55 μM in the resting, activated, and desensitized states, respectively, and inhibits NMDA currents in a use-dependent manner. Felbamate is a positive modulator of α₁β₂γ_2S, α₁β₃γ_2S, α₂β₂γ_2S, and α₂β₃γ_2S subunit-containing GABA_A receptors expressed in X. laevis oocytes, with negative modulation of GABA_A receptors containing the subunits α₁β₁, α₁β₃γ_2L, α₄β₁γ_2S, α₄β₃γ_2S, and α₆β₁γ_2S. It inhibits seizures induced by maximal electroshock, pentylenetetrazole , and picrotoxin in mice (ED₅₀s = 16.3, 5.51, and 5.23 mg/kg, respectively). Formulations containing felbamate have been used in the treatment of severe refractory seizures.