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 GABAA receptors that also has broad-spectrum inhibitory activity against excitatory amino acid receptors.1,2,3 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.1 Felbamate is a positive modulator of α1β2γ2S, α1β3γ2S, α2β2γ2S, and α2β3γ2S subunit-containing GABAA receptors expressed in X. laevis oocytes, with negative modulation of GABAA receptors containing the subunits α1β1, α1β3γ2L, α4β1γ2S, α4β3γ2S, and α6β1γ2S.2 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.
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)