A modified release pharmaceutical formulation includes about 30 70% N (2 amino 4 (fluorobenzylamino) phenyl) carbamic acid ethyl ester (retigabine) or a pharmaceutically acceptable salt solvate or hydrate thereof about 5 30% of a drug delivery matrix including hydroxypropylmethylcellulose (HPMC) and an enteric polymer. The pharmaceutical formulation produces a sustained plasma concentration of retigabine following administration to a subject for 4 20 hours longer than the time required for in vitro release of 80% of retigabine. The plasma concentration vs. time profile of this formulation is substantially flat over an extended period lasting for about 4 hours to about 36 hours. A method of treating a disorder characterized by nervous system hyperexcitability includes administering to a subject an effective amount of these pharmaceutical formulations.
