Design, synthesis and evaluation of anticonvulsant activity of pyridinyl-pyrrolidones: a pharmacophore hybrid approach.

Various 1-[6-(4-substituted phenyl)-3-cyano-4-(substituted phenyl)-pyridin-2-yl]-5-oxopyrrolidine-3-carboxylic acids (3a-t) were designed and synthesized by clubbing pyrrolidinones and pyridines, the two active anticonvulsant pharmacophores. All the synthesized compounds fulfilled the requirements of suggested pharmacophoric model for anticonvulsant activity. Their in vivo anticonvulsant evaluation was performed by maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) tests. The minimal motor impairment was assessed by rotorod test and the estimation of various liver enzymes was performed to check the magnitude of liver toxicity posed by the synthesized compounds. Compounds 3d and 3k displayed comparable anticonvulsant activity to the standard drugs with ED(50) values of 13.4 and 18.6 mg/kg in electroshock screen, repectively. The compounds 3d and 3k were also found to have encouraging anticonvulsant activity (ED(50)  = 86.1 and 271.6 mg/kg, respectively) in scPTZ screen. Interestingly, they did not show any sign of motor impairment at the maximum dose administered and were not toxic to the liver.