Discovery of novel hybrid pyrrolidin-2-one derivatives exhibiting potent antiseizure and antinociceptive effects in preclinical models

In the present study, a series of novel derivatives based on the pyrrolidin-2-one scaffold were designed using a framework combination approach, synthesized, and comprehensively evaluated through in vitro and in vivo assays conducted on Swiss albino male mice. The obtained hybrid molecules demonstrated potent and broad-spectrum antiseizure activity in key preclinical seizure models. Following intraperitoneal (i.p.) administration, compound (R)-9, identified as the lead molecule, provided robust protection across all tested seizure paradigms, with ED₅₀ values of 64.3 mg/kg (maximal electroshock test), 26.3 mg/kg (6 Hz, 32 mA), and 37.8 mg/kg (6 Hz, 44 mA). In addition, (R)-9 was active in the pentylenetetrazole (PTZ)-induced kindling model as well as in spontaneous electrographic bursting, an in vitro model of pharmacoresistant seizure-like activity at a concentration of 120 μM. Moreover, it significantly increased seizure threshold in the ivPTZ test. Importantly, (R)-9 also exhibited strong antinociceptive properties. No adverse effects on motor coordination and grip strength were observed at effective doses. Pharmacokinetic profiling and in vitro ADME-Tox evaluation showed satisfying drug-like characteristics of (R)-9, including metabolic stability in human liver microsomes, interaction with cytochrome P450 enzymes and hepatotoxicity (HepG2 cell line). In vitro binding and functional assays suggest a multimodal mechanism of action. Besides its TRPV1 antagonistic activity, (R)-9 effectively inhibited voltage-gated sodium channels at a concentration of 50 μM in electrophysiological studies. Collectively, these findings support the further preclinical development of (R)-9 as a promising candidate for the treatment of epilepsy and pain-related disorders.