TPA-023B

• CAT Number: I017211
• CAS Number: 425377-76-0
• Molecular Formula: C21H15F2N5O
• Molecular Weight: 391.37
• Purity: ≥95%
• Synonyms: 3-fluoro-2-[2-fluoro-5-[3-(2-hydroxypropan-2-yl)imidazo[1,2-b][1,2,4]triazin-7-yl]phenyl]benzonitrile
• InChI: InChI=1S/C21H15F2N5O/c1-21(2,29)18-11-26-28-17(10-25-20(28)27-18)12-6-7-15(22)14(8-12)19-13(9-24)4-3-5-16(19)23/h3-8,10-11,29H,1-2H3
• InChIKey: PCZLQMGFNUNVOM-UHFFFAOYSA-N
• SMILES: CC(C)(C1=NC2=NC=C(N2N=C1)C3=CC(=C(C=C3)F)C4=C(C=CC=C4F)C#N)O

TPA-023B is a high-affinity and orally active GABAA receptor α2/α3 subtype (Kis of 0.73 nM/2 nM) partial agonist and a α1 subtype (Ki of 1.8 nM) antagonist. TPA-023B has non-sedating anxiolytic-like properties[1].
TPA-023B also has high affinity for α5 subtype (Ki of 1.1 nM) of human recombinant GABAA receptor, but over 1500-fold lower for the α4- and α6 containing subtypes (Ki > 1000 nM). TPA-023B also has a comparable affinity for native rat GABAA receptors in different regions of the CNS (Ki of 0.32-0.99 nM in cerebellum, spinal cord and frontal cortex)[1].
TPA-023B antagonizes the ability of chlordiazepoxide to potentiate the GABA EC20-induced current in cells expressing the α1 subtype. More specifically, 3 μM chlordiazepoxide potentiates the GABA EC20 current by 105% and this effect could be reduced to 8% in the presence of 100 nM TPA-023B[1].
TPA-023B gives dose- and time-dependent occupancy of rat brain GABAA receptors as measured using an in vivo [3H]flumazenil binding assay, with 50% occupancy corresponding to a respective dose and plasma drug concentration of 0.09 mg/kg and 19 ng/mL[1].
TPA-023B is anxiolytic in rodent and primate (squirrel monkey) models of anxiety (elevated plus maze, fear-potentiated startle, conditioned suppression of drinking, conditioned emotional response) yet has no significant effects in rodent or primate assays of ataxia and/or myorelaxation (rotarod, chain-pulling, lever pressing), up to doses (10 mg/kg) corresponding to occupancy of greater than 99%[1].

Reference

[1]. Atack JR, et al. Preclinical and clinical pharmacology of TPA023B, a GABAA receptor α2/α3 subtype-selective partial agonist. J Psychopharmacol. 2011 Mar;25(3):329-44.
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