Amino acid derivatives with anticonvulsant activity

A series of benzylamides of N-alkylated, N-acylated or free nine cyclic and one linear amino acids as potential anticonvulsants have been synthesized. The structures of the obtained compounds were designed on the basis of the previously determined structure and physicochemical properties/anticvonvulsant activity relationship of the formerly synthesized compounds of this type. The obtained compounds were evaluated in mice after intraperitoneal (i.p.) administration, by maximal electroshock seizure test (MES test), subcutaneous (s.c.) pentylenetetrazol test (s.c. PTZ test) and by the rotarod neurotoxicity test (Tox test). The results were the basis for their classification into one of three classes of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) of the NIH. Three selected compounds were tested quantitatively in rats after oral administration. The MES ED50, s.c. PTZ ED50, Tox TD50 were determined and their protective index (PI) values were calculated. Anticonvulsant activity of the most promising compound (15) was examined in different seizure models. The respective ED50 and PI values of this compound were as follows: against bicuculline, 73 and 1.4; against PTZ, 47 and 2.2; against strychnine, 73 and 1.4; against pilocarpine 156, and 0.7; against kainic acid (2-carboxy-4-isopropenyl-3-pyrrolidineacetic acid), 39 and 2.6; against AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid), 10 and 10.3 and against NMDA (N-methyl-D-Aspartic acid), 114 and 0.9.