TPA-023 (MK-0777) is an

anxiolytic An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxiet ...

drug with a novel chemical structure, which is used in scientific research. It has similar effects to

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

drugs, but is structurally distinct and so is classed as a

nonbenzodiazepine Nonbenzodiazepines (), sometimes referred to colloquially as Z-drugs (as many of their names begin with the letter "z"), are a class of psychoactive drugs that are very benzodiazepine-like in nature. They are used in the treatment of sleep proble ...

anxiolytic. It is a subtype-selective, mixed allosteric modular at the benzodiazepine location on GABA_A receptors, where it acts as a

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist. They may also be considered ligands which display both agonistic and antagonis ...

at the α2 and α3 subtypes, but as a silent

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, ri ...

at α1 and α5 subtypes. It has primarily

and

anticonvulsant Anticonvulsants (also known as antiepileptic drugs or recently as antiseizure drugs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of ...

effects in animal tests, but with no

sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but ...

effects even at 50 times the effective anxiolytic dose. In human trials on healthy volunteers, TPA-023 was comparable to

lorazepam Lorazepam, sold under the brand name Ativan among others, is a benzodiazepine medication. It is used to treat anxiety disorders, trouble sleeping, severe agitation, active seizures including status epilepticus, alcohol withdrawal, and che ...

, but had much less side effects on cognition, memory, alertness or coordination. In Phase II trials, the compound was significantly superior to placebo without inducing sedation. The clinical development was halted due to preclinical toxicity (cataract) in long term dosing studies. TPA-023 is well absorbed following oral administration and extensively metabolised by the liver, with a half-life of 6.7 hours. The main enzyme involved in its metabolism is

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules ( xenobiotics), such as toxins or drugs, so that they can be removed from ...

, with some contribution by CYP3A5.

References

{{GABAAR PAMs Anxiolytics Ethers Fluoroarenes Triazoles Triazolopyridazines GABAA receptor positive allosteric modulators Tert-butyl compounds