Discovery and\nProfiling of New Multimodal Phenylglycinamide\nDerivatives as Potent Antiseizure and Antinociceptive Drug Candidates

We developed a focused series of original phenyl-glycinamide\nderivatives\nwhich showed potent activity across <i>in vivo</i> mouse\nseizure models, namely, maximal electroshock (MES) and 6 Hz (using\nboth 32 and 44 mA current intensities) seizure models. Following intraperitoneal\n(<i>i.p</i>.) administration, compound <b>(</b><b><i>R</i></b><b>)-32</b>, which was identified\nas a lead molecule, demonstrated potent protection against all seizure\nmodels with ED<sub>50</sub> values of 73.9 mg/kg (MES test), 18.8\nmg/kg (6 Hz, 32 mA test), and 26.5 mg/kg (6 Hz, 44 mA test). Furthermore, <b>(</b><b><i>R</i></b><b>)-32</b> demonstrated\nefficacy in both the PTZ-induced kindling paradigm and the <i>iv</i>PTZ seizure threshold test. The expression of neurotrophic\nfactors, such as mature brain-derived neurotrophic factor (mBDNF)\nand nerve growth factor (NGF), in the hippocampus and/or cortex of\nmice, and the levels of glutamate and GABA were normalized after PTZ-induced\nkindling by <b>(<i>R</i>)-32</b>. Importantly, besides\nantiseizure activity, (<b><i>R</i></b>)<b>-32</b> demonstrated potent antinociceptive efficacy in formalin-induced\npain, capsaicin-induced pain, as well as oxaliplatin- and streptozotocin-induced\nperipheral neuropathy in mice (<i>i.p</i>.). No influence\non muscular strength and body temperature in mice was observed. Pharmacokinetic\nstudies and <i>in vitro</i> ADME-Tox data (<i>i.e.</i>, high metabolic stability in human liver microsomes, a weak influence\non CYPs, no hepatotoxicity, satisfactory passive transport, <i>etc.</i>) proved favorable drug-like properties of (<b><i>R</i></b>)<b>-32</b>. Thermal stability of (<b><i>R</i></b>)-<b>32</b> shown in thermogravimetry and\ndifferential scanning calorimetry gives the opportunity to develop\ninnovative oral solid dosage forms loaded with this compound. The <i>in vitro</i> binding and functional assays indicated its multimodal\nmechanism of action. (<b><i>R</i></b>)<b>-32</b>, beyond TRPV1 antagonism, inhibited calcium and sodium currents\nat a concentration of 10 μM. Therefore, the data obtained in\nthe current studies justify a more detailed preclinical development\nof (<b><i>R</i></b>)<b>-32</b> for epilepsy\nand pain indications.