Felbamate-d₄is 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_Areceptors that also has broad-spectrum inhibitory activity against excitatory amino acid receptors.^1,2,3It 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.¹Felbamate is a positive modulator of α₁β₂γ_2S, α₁β₃γ_2S, α₂β₂γ_2S, and α₂β₃γ_2Ssubunit-containing GABA_Areceptors expressed inX. laevisoocytes, with negative modulation of GABA_Areceptors containing the subunits α₁β₁, α₁β₃γ_2L, α₄β₁γ_2S, α₄β₃γ_2S, and α₆β₁γ_2S.²It 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.

1.Kuo, C.-C., Lin, B.-J., Chang, H.-R., et al.Use-dependent inhibition of the N-methyl-D-aspartate currents by felbamate: a gating modifier with selective binding to the desensitized channelsMol. Pharmacol.65(2)370-380(2004) 2.Simeone, T.A., Otto, J.F., Wilcox, K.S., et al.Felbamate is a subunit selective modulator of recombinant γ-aminobutyric acid type A receptors expressed in Xenopus oocytesEur. J. Pharmacol.552(1-3)31-35(2006) 3.Domenici, M.R., Sagratella, S., Ongini, E., et al.Felbamate displays in vitro antiepileptic effects as a broad spectrum excitatory amino acid receptor antagonistEur. J. Pharmacol.271(2-3)259-263(1994)