Armodafinil

Absorption

Tmax is 2 hours when fasted and can be delayed approximately 2-4 hours by food, potentially affecting the onset of action.

Description

Armodafinil, an α1-adrenoceptor agonist, was launched for the oral treatment of excessive sleepiness associated with narcolepsy, SWSD, and obstructive sleep apnea/hypopnea syndrome (OSA). It is the R-enantiomer of modafinil, which is a previously marketed wake-promoting agent. The key differentiator for armodafinil is its longer pharmacokinetic half-life as compared with the S-enantiomer (10-14 hvs.3-4h). At therapeutic concentrations, armodafinil does not bind to most of the potentially relevant receptors for sleep/wake regulation (e.g., serotonin, dopamine, and adenosine receptors) or transporters of neurotransmitters or enzymes involved in sleep/wake regulation (e.g., serotonin, norepinephrine, and phosphodiesterase VI transporters). Both armodafinil and modafinil block dopamine reuptake by binding to the dopamine transporter and increasing dopamine concentrations in certain regions of the brain. However, dopamine receptor antagonists (e.g., haloperidol) and dopamine synthesis inhibitors (e.g., α-methyl-p-tyrosine) do not block modafinil’s action.
In addition to its wake-promoting effects and ability to increase locomotor activity in animals, modafinil produces psychoactive and euphoric effects, alterations in mood, perception, thinking, and feelings typical of other CNS stimulants in humans. Modafinil was also partially discriminated as stimulant-like. However, the potential for abuse and dependency appears to be lower for modafinil than amphetamine-like stimulants.The most common adverse events associated with armodafinil included headache, nausea, dizziness, and insomnia.

Chemical properties

White Solid

Originator

Cephalon (US)

The Uses of Armodafinil

Used for treatment of excessive sleepiness, a1-adrenoceptor agonist

The Uses of Armodafinil

Used for treatment of excessive sleepiness, α1-adrenoceptor agonist.

The Uses of Armodafinil

analeptic

Indications

Investigated for use/treatment in sleep disorders, obstructive sleep apnea, schizophrenia and schizoaffective disorders, depression, and bipolar disorders.

Background

Armodafinil is the enantiopure of the wakefulness-promoting agent modafinil (Provigil), and is indicated to improve wakefulness in adult patients with excessive sleepiness associated with obstructive sleep apnea (OSA), narcolepsy, or shift work disorder (SWD). Research has shown that armodafinil significantly improves driving simulator performance in patients with SWD. Armodafinil consists of the (?)-R-enantiomer of the racemic modafinil. Armodafinil is produced by the pharmaceutical company Cephalon Inc. (a wholly owned subsidiary of Teva Pharmaceutical Industries Ltd.) and was approved by the U.S. Food and Drug Administration (FDA) in June 2007.

Definition

ChEBI: A 2-[(diphenylmethyl)sulfinyl]acetamide that has R configuration at the sulfur atom. Like its racemate, modafinil, it is used for the treatment of sleeping disorders such as narcolepsy, obstructive sleep apnoea, and shift-work sleep disord r. Peak concentration in the blood later occurs later following administration than with modafinil, so it is thought that armodafinil may be more effective than modafinil in treating people with excessive daytime sleepiness.

brand name

Nuvigil

Synthesis

Armodafinil can be obtained starting from (+)-2( diphenylmethylsulfinyl)acetic acid via optical resolution using S-(-)-amethylbenzylamine, followed by esterification to the methyl ester and subsequent amidation with ammonium hydroxide. It can also be derived enantioselectively from 2-(diphenylmethylthio)acetamide via asymmetric oxidation with cumene hydroperoxide and titanium isopropoxide-S,Sdiethyl tartrate complex.

Metabolism

In vitro and in vivo data show that armodafinil undergoes hydrolytic deamidation, S-oxidation, and aromatic ring hydroxylation, with subsequent glucuronide conjugation of the hydroxylated products. Amide hydrolysis is the single most prominent metabolic pathway, with sulfone formation by cytochrome P450 (CYP) 3A4/5 being next in importance. The other oxidative products are formed too slowly in vitro to enable identification of the enzyme(s) responsible. Only two metabolites reach appreciable concentrations in plasma (i.e., R-modafinil acid and modafinil sulfone). Data specific to armodafinil disposition are not available.