@article{
author = "Pandey, Kamal P. and Divović, Branka and Rashid, Farjana and Golani, Lalit K. and Cerne, Rok and Zahn, Nicolas M. and Meyer, Michelle Jean and Arnold, Leggy A. and Sharmin, Dishary and Mian, Md Yeunus and Smith, Jodi L. and Ping, Xingjie and Jin, Xiaoming and Lippa, Arnold and Tiruveedhula, Phani Babu V. V. N. and Cook, James M. and Savić, Miroslav and Witkin, Jeffrey M.",
year = "2023",
abstract = "To provide back-up compounds to support the development of the GABAA receptor (GABAAR) potentiator KRM-II-81, three novel analogs were designed: replacing the pyridinyl with 2'-Cl-phenyl (FR-II-60), changing the positions of the N and O atoms in the oxazole ring with addition of an ethyl group (KPPIII-34 and KPP-III-51), or substituting a Br atom for the ethynyl of KRM-II-81 (KPP-III-34). The compounds bound to brain GABAARs. Intraperitoneal administration of FR-II-60 and KPP-III-34 produced anticonvulsant activity in mice [maximal electroshock (MES)-induced seizures or 6 Hz-induced seizures], whereas KPPIII-51 did not. Although all compounds were orally bioavailable, structural changes reduced the plasma and brain (FR-II-60 and KPP-III-51) exposures relative to KRM-II-81. Oral administration of each compound produced dose-dependent increases in the latency for both clonic and tonic seizures and the lethality induced by pentylenetetrazol (PTZ) in mice. Since KPP-III-34 produced the highest brain area under the curve (AUC) exposures, it was selected for further profiling. Oral administration of KPP-III-34 suppressed seizures in corneal-kindled mice, hippocampal paroxysmal discharges in mesial temporal lobe epileptic mice, and PTZ-induced convulsions in rats. Only transient sensorimotor impairment was observed in mice, and doses of KPP-III-34 up to 500 mg/kg did not produce impairment in rats. Molecular docking studies demonstrated that all compounds displayed a reduced propensity for binding to a1His102 compared with the sedating compound alprazolam; the bromine-substituted KPP-III-34 achieved the least interaction. Overall, these findings document the oral bioavailability and anticonvulsant efficacy of three novel analogs of KRM-II-81 with reduced sedative effects. SIGNIFICANCE STATEMENT A new non-sedating compound, KRM-II-81, with reduced propensity for tolerance is moving into clinical development. Three new analogs were orally bioavailable, produced anticonvulsant effects in rodents, and displayed low sensorimotor impairment. KPP-III-34 demonstrated efficacy in models of pharmacoresistant epilepsy. Docking studies demonstrated a low propensity for compound binding to the a1His102 residue implicated in sedation. Thus, three additional structures have been added to the list of non-sedating imidazodiazepine anticonvulsants that could serve as backups in the clinical development of KRM-II-81. Copyright © 2023 by The American Society for Pharmacology and Experimental Therapeutics.",
publisher = "American Society for Pharmacology and Experimental Therapy (ASPET)",
journal = "Journal of Pharmacology and Experimental Therapeutics",
title = "Structural Analogs of the GABAkine KRM-II-81 Are Orally Bioavailable Anticonvulsants without Sedation",
volume = "385",
number = "1",
pages = "50-61",
doi = "10.1124/jpet.122.001362"
}
