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Trade names | Sidnocarb, Sydnocarb, Synocarb |
Other names | Fensidnimine; Pharmaneocarb; Sydnocarbum; N-Phenylcarbamoyl-3-(β-phenylisopropyl)sydnonimine; 3-(β-Phenylisopropyl)-N-phenylcarbamoylsydnonimine; Armesocarb; MLR-1019 |
Routes of administration | Oral |
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Metabolism | Hepatic |
Excretion | Renal |
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Formula | C18H18N4O2 |
Molar mass | 322.368 g·mol−1 |
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Mesocarb, sold under the brand name Sidnocarb or Sydnocarb and known by the developmental code name MLR-1019, is a psychostimulant medication which has been used in the treatment of psychiatric disorders and for a number of other indications in the Soviet Union and Russia. [2] [3] It is currently under development for the treatment of Parkinson's disease and sleep disorders. [4] [5] It is taken by mouth.
The drug is a selective dopamine reuptake inhibitor (DRI). [6] [7] [8] [9] It is an unusual and unique DRI, acting as a negative allosteric modulator and non-competitive inhibitor of the dopamine transporter (DAT). [6] [7] [8] Chemically, mesocarb contains amphetamine within its structure but has been modified and extended at the amine with a sydnone imine-containing moiety. [10] [2] [3]
Mesocarb was first described by 1971. [2] [11] [12] [9] In 2021, its nature as a DAT allosteric modulator was reported. [6] [7] [8] As of April 2023, mesocarb is in phase 1 clinical trials for Parkinson's disease and in the preclinical stage of development for sleep disorders. [5]
Mesocarb was originally developed in the Soviet Union in the 1970s [13] [14] for a variety of indications including asthenia, apathy, adynamia, and some clinical aspects of depression and schizophrenia. [15] [16] Mesocarb was used for counteracting the sedative effects of benzodiazepines, [17] increasing workload capacity and cardiovascular function, [18] treatment of attention deficit hyperactivity disorder (ADHD) in children, [19] [20] as a nootropic, [21] and as a drug to enhance resistance to extremely cold temperatures. [22] [23] It has also been reported to have antidepressant and anticonvulsant properties. [24]
Mesocarb was sold in Russia as 5 mg oral tablets under the brand name Sydnocarb.[ citation needed ]
Mesocarb has been found to act as a selective dopamine reuptake inhibitor (DRI) by blocking the actions of the dopamine transporter (DAT), [9] [25] and lacks the dopamine release characteristic of stimulants such as dextroamphetamine. [26] [27] [28] It was the most selective DAT inhibitor amongst an array of other DAT inhibitors to which it was compared. [25]
The inhibitory potencies (IC50 ) of mesocarb at the human monoamine transporters in vitro have been reported to be 0.49 ± 0.14 µM at the DAT, 34.9 ± 14.08 µM at the norepinephrine transporter (NET) (71-fold lower), and 494.9 ± 17.00 µM at the serotonin transporter (1,010-fold lower). [8]
In 2021, it was discovered that mesocarb is not a conventional DRI but acts as a DAT allosteric modulator or non-competitive inhibitor and has atypical effects relative to conventional DRIs. [6] [7] [8]
Hydroxylated metabolites can be detected in urine for up to 10 days after consumption. [29]
Mesocarb had erroneously been referred to as a prodrug of amphetamine. [30] However, this was based on older literature that relied on gas chromatography as an analytical method. Subsequently, with the advent of mass spectroscopy, it has been shown that presence of amphetamine in prior studies was an artifact of the gas chromatography method. [31] More recent studies using mass spectroscopy show that negligible levels of amphetamine are released from mesocarb metabolism. [29]
Mesocarb, also known as 3-(β-phenylisopropyl)-N-phenylcarbamoylsydnonimine, is a substituted phenethylamine and amphetamine and a mesoionic sydnone imine. [10] [2] [3] It has the amphetamine backbone present, except that the RN has a complicated imine side chain present. [10] [2] [3]
It is structurally related to feprosidnine (Sydnophen; 3-(α-methylphenylethyl)sydnone imine). [24]
Feprosidnine (Sydnophen) is converted from the hydrochloride salt (1) into the freebase amine (2). This is then treated with phenylisocyanate (3).
Mesocarb was first described in the scientific literature by 1971. [2] [11] [12] [9]
Mesocarb is the generic name of the drug and its INN . [10] It is also known by the synonym fensidnimine as well as by the brand names Sydnocarb and Synocarb. [2] [3] [10] [34] The drug is additionally known by its developmental code name MLR-1019 (for Parkinson's disease and other indications). [5]
Mesocarb is almost unknown in the western world and is neither used in medicine nor studied scientifically to any great extent outside of Russia and other countries in the former Soviet Union. It has however been added to the list of drugs under international control and is a scheduled substance in most countries, despite its multiple therapeutic applications and reported lack of significant abuse potential. [35]
Mesocarb has been under development for the treatment of Parkinson's disease since 2016. [4] [5] As of April 2023, it is in phase 1 clinical trials for this indication. [5] A phase 2 trial is being planned. [5] It is also in the preclinal stage of development for sleep disorders. [5] It was previously approved for treatment of psychiatric disorders, but it was withdrawn from the market. [5]
Amphetamine is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. Amphetamine was discovered as a chemical in 1887 by Lazăr Edeleanu, and then as a drug in the late 1920s. It exists as two enantiomers: levoamphetamine and dextroamphetamine. Amphetamine properly refers to a specific chemical, the racemic free base, which is equal parts of the two enantiomers in their pure amine forms. The term is frequently used informally to refer to any combination of the enantiomers, or to either of them alone. Historically, it has been used to treat nasal congestion and depression. Amphetamine is also used as an athletic performance enhancer and cognitive enhancer, and recreationally as an aphrodisiac and euphoriant. It is a prescription drug in many countries, and unauthorized possession and distribution of amphetamine are often tightly controlled due to the significant health risks associated with recreational use.
Methylphenidate, sold under the brand names Ritalin and Concerta among others, is a central nervous system (CNS) stimulant used medically to treat attention deficit hyperactivity disorder (ADHD) and, to a lesser extent, narcolepsy. It is a primary medication for ADHD ; it may be taken by mouth or applied to the skin, and different formulations have varying durations of effect. For ADHD, the effectiveness of methylphenidate is comparable to atomoxetine but modestly lower than amphetamines, alleviating the executive functioning deficits of sustained attention, inhibition, working memory, reaction time and emotional self-regulation.
Monoamine transporters (MATs) are proteins that function as integral plasma-membrane transporters to regulate concentrations of extracellular monoamine neurotransmitters. The three major classes are serotonin transporters (SERTs), dopamine transporters (DATs), and norepinephrine transporters (NETs) and are responsible for the reuptake of their associated amine neurotransmitters. MATs are located just outside the synaptic cleft (peri-synaptically), transporting monoamine transmitter overflow from the synaptic cleft back to the cytoplasm of the pre-synaptic neuron. MAT regulation generally occurs through protein phosphorylation and post-translational modification. Due to their significance in neuronal signaling, MATs are commonly associated with drugs used to treat mental disorders as well as recreational drugs. Compounds targeting MATs range from medications such as the wide variety of tricyclic antidepressants, selective serotonin reuptake inhibitors such as fluoxetine (Prozac) to stimulant medications such as methylphenidate (Ritalin) and amphetamine in its many forms and derivatives methamphetamine (Desoxyn) and lisdexamfetamine (Vyvanse). Furthermore, drugs such as MDMA and natural alkaloids such as cocaine exert their effects in part by their interaction with MATs, by blocking the transporters from mopping up dopamine, serotonin, and other neurotransmitters from the synapse.
A dopamine reuptake inhibitor (DRI) is a class of drug which acts as a reuptake inhibitor of the monoamine neurotransmitter dopamine by blocking the action of the dopamine transporter (DAT). Reuptake inhibition is achieved when extracellular dopamine not absorbed by the postsynaptic neuron is blocked from re-entering the presynaptic neuron. This results in increased extracellular concentrations of dopamine and increase in dopaminergic neurotransmission.
A norepinephrine reuptake inhibitor or noradrenaline reuptake inhibitor or adrenergic reuptake inhibitor (ARI), is a type of drug that acts as a reuptake inhibitor for the neurotransmitters norepinephrine (noradrenaline) and epinephrine (adrenaline) by blocking the action of the norepinephrine transporter (NET). This in turn leads to increased extracellular concentrations of norepinephrine and epinephrine and therefore can increase adrenergic neurotransmission.
The dopamine transporter is a membrane-spanning protein coded for in humans by the SLC6A3 gene, that pumps the neurotransmitter dopamine out of the synaptic cleft back into cytosol. In the cytosol, other transporters sequester the dopamine into vesicles for storage and later release. Dopamine reuptake via DAT provides the primary mechanism through which dopamine is cleared from synapses, although there may be an exception in the prefrontal cortex, where evidence points to a possibly larger role of the norepinephrine transporter.
Phenylpiracetam, is a phenyl-substituted analog of the drug piracetam. It was developed in 1983 as a medication for Soviet Cosmonauts to treat the prolonged stresses of working in space. Phenylpiracetam was created at the Russian Academy of Sciences Institute of Biomedical Problems in an effort led by psychopharmacologist Valentina Ivanovna Akhapkina. In Russia it is now available as a prescription drug. Research on animals has indicated that phenylpiracetam may have anti-amnesic, antidepressant, anticonvulsant, anxiolytic, and memory enhancement effects.
Dopaminergic means "related to dopamine", a common neurotransmitter. Dopaminergic substances or actions increase dopamine-related activity in the brain.
Phenyltropanes (PTs) were originally developed to reduce cocaine addiction and dependency. In general these compounds act as inhibitors of the plasmalemmal monoamine reuptake transporters. This research has spanned beyond the last couple decades, and has picked up its pace in recent times, creating numerous phenyltropanes as research into cocaine analogues garners interest to treat addiction.
Feprosidnine (Sydnophen) is a stimulant drug which was developed in the USSR in the 1970s. It is structurally related to another Russian drug mesocarb but unlike mesocarb, was withdrawn earlier from production. In comparison with mesocarb it has own antidepressant activity, which makes it useful in treating depressions. Indications of feprosidnine included apathic, asthenic depressions, fatigue, apathic syndrome, narcolepsy and other similar conditions. Therapeutic range of doses: 10-50mg a day. Sydnophen has multiple mechanisms of action, the relative importance of which has not been clearly established. Effects on the body include reversible monoamine oxidase inhibition, cholinergic, adrenergic, opioid and nitric oxide donating actions, all of which may contribute to its pharmacological effects to some extent.
Bromantane, sold under the brand name Ladasten, is an atypical central nervous system (CNS) stimulant and anxiolytic drug of the adamantane family that is related to amantadine and memantine. Medically, it is approved in Russia for the treatment of neurasthenia. Although the effects of bromantane have been determined to be dependent on the dopaminergic and possibly serotonergic neurotransmitter systems, its exact mechanism of action is unknown, and is distinct in its properties relative to typical stimulants such as amphetamine. Bromantane has sometimes been described as an actoprotector.
A monoamine releasing agent (MRA), or simply monoamine releaser, is a drug that induces the release of a monoamine neurotransmitter from the presynaptic neuron into the synapse, leading to an increase in the extracellular concentrations of the neurotransmitter. Many drugs induce their effects in the body and/or brain via the release of monoamine neurotransmitters, e.g., trace amines, many substituted amphetamines, and related compounds.
A dopamine releasing agent (DRA) is a type of drug which induces the release of dopamine in the body and/or brain. No selective and robust DRAs are currently known. On the other hand, many releasing agents of both dopamine and norepinephrine and of serotonin, norepinephrine, and dopamine are known. Serotonin–dopamine releasing agents (SDRAs), for instance 5-chloro-αMT, are much more rare and are not selective for dopamine release but have also been developed. Examples of major NDRAs include the psychostimulants amphetamine and methamphetamine, while an example of an SNDRA is the entactogen methylenedioxymethamphetamine (MDMA). These drugs are frequently used for recreational purposes and encountered as drugs of abuse. Selective DRAs, as well as NDRAs, have medical applications in the treatment of attention deficit hyperactivity disorder (ADHD).
RTI(-4229)-113 is a stimulant drug which acts as a potent and fully selective dopamine reuptake inhibitor (DRI). It has been suggested as a possible substitute drug for the treatment of cocaine addiction. "RTI-113 has properties that make it an ideal medication for cocaine abusers, such as an equivalent efficacy, a higher potency, and a longer duration of action as compared to cocaine." Replacing the methyl ester in RTI-31 with a phenyl ester makes the resultant RTI-113 fully DAT specific. RTI-113 is a particularly relevant phenyltropane cocaine analog that has been tested on squirrel monkeys. RTI-113 has also been tested against cocaine in self-administration studies for DAT occupancy by PET on awake rhesus monkeys. The efficacy of cocaine analogs to elicit self-administration is closely related to the rate at which they are administered. Slower onset of action analogs are less likely to function as positive reinforcers than analogues that have a faster rate of onset.
Echinopsidine (Adepren) is an antidepressant that was under development in Bulgaria for the treatment of depression. It increases serotonin, norepinephrine, and dopamine levels in the brain and is believed to act as a monoamine oxidase inhibitor (MAOI). Echinopsidine is found naturally in Echinops echinatus along with the related alkaloids echinopsine and echinozolinone.
Amphetamine dependence refers to a state of psychological dependence on a drug in the amphetamine class. Stimulants such as amphetamines and cocaine do not cause somatic symptoms upon cessation of use but rather neurological-based mental symptoms.
SoRI-20041 is an "antagonist-like" allosteric modulator of amphetamine-induced dopamine release. SoRI-20041 is believed to be the first example of a drug that separately modulates uptake versus release in the dopamine transporter ; it produces the same effects as SoRI-20040 and SoRI-9804 in uptake assays and binding assays, inhibiting the re-uptake of dopamine, but does not modulate d-amphetamine-induced DA release by inhibiting that as well, like 'agonists' of the series do.
A monoamine reuptake inhibitor (MRI) is a drug that acts as a reuptake inhibitor of one or more of the three major monoamine neurotransmitters serotonin, norepinephrine, and dopamine by blocking the action of one or more of the respective monoamine transporters (MATs), which include the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT). This in turn results in an increase in the synaptic concentrations of one or more of these neurotransmitters and therefore an increase in monoaminergic neurotransmission.
Amphetamine type stimulants (ATS) are a group of synthetic drugs that are chemical derivatives of the parent compound alpha-methylphenethylamine, also known as amphetamine. Common ATS includes amphetamine, methamphetamine, ephedrine, pseudoephedrine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxyethylamphetamine (MDEA). ATS when used illicitly has street names including ice, meth, crystal, crank, bennies, and speed. Within the group of amphetamine-type stimulants, there are also prescription drugs including mixed amphetamine salts, dextroamphetamine, and lisdexamfetamine.
JJC8-088 is a dopamine reuptake inhibitor (DRI) that was derived from the wakefulness-promoting agent modafinil.
Mesocarb (sydnocarb) (13) and Feprosidnine (sydnofen) (14) are stimulants developed in Russia in the 1970s. Mesocarb is sold as a drug in Russia. However, it is almost unknown in Western countries and is not used in medicine. It has been shown to act as a dopamine reuptake inhibitor, antidepressant, and anticonvulsant [7, 8].