VIGABATRIN

Описание

Vigabatrin, the gamma-vinyl derivative of GABA, is a new anticonvulsant reportedly effective in the treatment of intractable seizures unresponsive to currently available therapy. Mechanistically vigabatrin is a potent irreversible GABA aminotransferase inhibitor which modifies the enzyme's active-site by Michael addition. Other potential indications have been suggested for vigabatrin, including depression and schizophrenia.

Химические свойства

White or almost white powder.

Использование

Vigabatrin is a selective GABA transaminase inhibitor.

Определение

ChEBI: A gamma-amino acid having a gamma-vinyl GABA structure. It is an irreversible inhibitor of gamma-aminobutyric 664 acid transaminase

Всемирная организация здравоохранения(ВОЗ)

Vigabatrin, an irreversible inhibitor of GABA-transaminase was introduced in 1989 as a anticonvulsant for management of epilepsy unresponsive to other antiepilepsy agents. In 1991 it was refused registration in Norway because it induced toxic changes, including microvacuolation in the brain of two animal species, at doses that are close to therapeutic dosage levels in man. It is still marketed in Sweden and the United Kingdom.

Биологические функции

Vigabatrin (Sabril) is a relatively specific irreversible inhibitor of GABA-transaminase (GABA-T), the major enzyme responsible for the metabolism of GABA in the mammalian CNS. As a result of inhibition of GABA-T, there is an increase in the concentration of GABA in the brain and consequently an increase in inhibitory neurotransmission. Vigabatrin is well absorbed orally and is distributed to all body systems.The major route of elimination for vigabatrin is renal excretion of the parent compound; no metabolites have been identified in humans.
At present, the primary indication for vigabatrin is in the treatment of patients with partial seizures, but it appears to be an effective and generally well tolerated antiepileptic medication for other seizure types as well. It should not be used in patients with absence epilepsy or with myoclonic seizures. Vigabatrin is not approved as an AED in the United States, although it is approved in many other countries.

Общее описание

Vigabatrin, a 4-vinyl analog of GABA, produces its pharmacologicalaction by irreversibly blocking GABA catabolismcatalyzed by GABA-T as discussed earlier. It is marketedin Europe and Canada as an adjunctive treatment ofpatients with partial seizures, but it has yet to gain FDA approvalin the United States even after extensive clinical trials.The main concern with this drug is its ability to causea reversible visual field defect associated with retinal functionin the eyes.

Биологическая активность

Selective GABA-T inhibitor. Anticonvulsant.

Синтез

The reaction of 1,4-dichloro-2- butene with diethyl malonate in the presence of sodium ethoxide as catalyst in refluxing ethanol gives 1,1-bis(ethoxycarbonyl)-2-vinylcyclopropane (8), which by reaction with gaseous ammonia in DMF is converted into 3-carboxamido- 5-vinyl-2-pyrrolidone (9). This compound is treated with HCl in refluxing acetic acid to yield vigabatrin.