Structure and physicochemical properties of N-[2-amino-4-(4-fluorobenzylamino)-phenyl]ethylcarbamate, retigabine

The structure of the anticonvulsant substance N-[2-amino-4-(4-fluorobenzyla mino)-phenyl]ethylcarbamate (INN: retigabine) was proved by IR, UV, H-1 NMR , C-13 NMR and mass spectra. Retigabine is practically insoluble in a neutr al aqueous medium at 20 degrees C (S similar to 0.07 g/l). The solubility o f the substance in 0.1 N HCl is about 16 g/l. In DMF, Retiga is freely solu ble (S similar to 186 g/l). The pK-value is about 3.7. The partition coeffi cient P = C-Octanol/C-Water bei 37 degrees C ranging from 0.4 at pH similar to 1 to about 150 at pH greater than or equal to 5.