In chemistry, an enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable, much as one's left and right hands are mirror images of each other that cannot appear identical simply by reorientation. A single chiral atom or similar structural feature in a compound causes that compound to have two possible structures which are non-superposable, each a mirror image of the other. Each member of the pair is termed an enantiomorph ; the structural property is termed enantiomerism. The presence of multiple chiral features in a given compound increases the number of geometric forms possible, though there may still be some perfect-mirror-image pairs.
Escitalopram, sold under the brand names Cipralex and Lexapro, among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Escitalopram is mainly used to treat major depressive disorder or generalized anxiety disorder. It is taken by mouth. It is available commercially exclusively as the oxalate salt.
Citalopram, sold under the brand name Celexa among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used to treat major depressive disorder, obsessive compulsive disorder, panic disorder, and social phobia. The antidepressant effects may take one to four weeks to occur. It is taken by mouth.
Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin-norepinephrine reuptake inhibitor (SNRI) class. It is used to treat major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder, and social phobia. It may also be used for chronic pain. It is taken by mouth.
Amoxapine, sold under the brand name Asendin among others, is a tricyclic antidepressant (TCAs). It is the N-demethylated metabolite of loxapine. Amoxapine first received marketing approval in the United States in 1992.
Forest Laboratories was a company in the pharmaceutical industry incorporated in Delaware, with its principal office in New York City. It was known for licensing European pharmaceuticals for sale in the United States. On July 1, 2014, the company was acquired by Actavis.
Adinazolam is a tranquilizer of the triazolobenzodiazepine (TBZD) class, which are benzodiazepines (BZDs) fused with a triazole ring. It possesses anxiolytic, anticonvulsant, sedative, and antidepressant properties. Adinazolam was developed by Dr. Jackson B. Hester, who was seeking to enhance the antidepressant properties of alprazolam, which he also developed. Adinazolam was never FDA approved and never made available to the public market, however it has been sold as a designer drug.
Ethyl loflazepate is a drug which is a benzodiazepine derivative. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. In animal studies it was found to have low toxicity, although in rats evidence of pulmonary phospholipidosis occurred with pulmonary foam cells developing with long-term use of very high doses. Its elimination half-life is 51–103 hours. Its mechanism of action is similar to other benzodiazepines. Ethyl loflazepate also produces an active metabolite which is stronger than the parent compound. Ethyl loflazepate was designed to be a prodrug for descarboxyloflazepate, its active metabolite. It is the active metabolite which is responsible for most of the pharmacological effects rather than ethyl loflazepate. The main metabolites of ethyl loflazepate are descarbethoxyloflazepate, loflazepate and 3-hydroxydescarbethoxyloflazepate. Accumulation of the active metabolites of ethyl loflazepate are not affected by those with kidney failure or impairment. The symptoms of an overdose of ethyl loflazepate include sleepiness, agitation and ataxia. Hypotonia may also occur in severe cases. These symptoms occur much more frequently and severely in children. Death from therapeutic maintenance doses of ethyl loflazepate taken for 2 – 3 weeks has been reported in 3 elderly patients. The cause of death was asphyxia due to benzodiazepine toxicity. High doses of the antidepressant fluvoxamine may potentiate the adverse effects of ethyl loflazepate.
Allosteric serotonin reuptake inhibitor is a type of selective serotonin reuptake inhibitor (SSRI). Currently only escitalopram, the S stereoisomer of the SSRI citalopram is included in this category. It is based on the observation that the R isomer of citalopram can decrease the potency and inhibit the effects of the S isomer, probably through an allosteric interaction between two distinct, non-overlapping binding sites for the two different isomers on the serotonin transporter. Escitalopram, thus, binds not only to the primary site, but also to the allosteric site. From known SSRIs also paroxetine has action to the allosteric site, about half potency of escitalopram.
Fluoxetine, sold under the brand names Prozac and Sarafem among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used for the treatment of major depressive disorder, obsessive–compulsive disorder (OCD), bulimia nervosa, panic disorder, and premenstrual dysphoric disorder. It is also approved for treatment of major depressive disorder in adolescents and children 8 years of age and over. It has also been used to treat premature ejaculation. Fluoxetine is taken by mouth.
A serotonin reuptake inhibitor (SRI) is a type of drug which acts as a reuptake inhibitor of the neurotransmitter serotonin by blocking the action of the serotonin transporter (SERT). This in turn leads to increased extracellular concentrations of serotonin and, therefore, an increase in serotonergic neurotransmission. It is a type of monoamine reuptake inhibitor (MRI); other types of MRIs include dopamine reuptake inhibitors and norepinephrine reuptake inhibitors.
The number of new psychiatric drugs, and especially antidepressants on the market in Japan, is significantly less than Western countries.
A reuptake inhibitor (RI) is a type of drug known as a reuptake modulator that inhibits the plasmalemmal transporter-mediated reuptake of a neurotransmitter from the synapse into the pre-synaptic neuron. This leads to an increase in extracellular concentrations of the neurotransmitter and an increase in neurotransmission. Various drugs exert their psychological and physiological effects through reuptake inhibition, including many antidepressants and psychostimulants.
Desmethylcitalopram is an active metabolite of the antidepressant drugs citalopram (racemic) and escitalopram. Like citalopram and escitalopram, desmethylcitalopram functions as a selective serotonin reuptake inhibitor (SSRI), and is responsible for some of its parents' therapeutic benefits.
Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions.
N-Desalkylflurazepam is a benzodiazepine analog and an active metabolite of several other benzodiazepine drugs including flurazepam, flutoprazepam, fludiazepam, midazolam, flutazolam, quazepam, and ethyl loflazepate. It is long-acting, prone to accumulation, and binds unselectively to the various benzodiazepine receptor subtypes. It has been sold as a designer drug from 2016 onward.
Pharmacometabolomics, also known as pharmacometabonomics, is a field which stems from metabolomics, the quantification and analysis of metabolites produced by the body. It refers to the direct measurement of metabolites in an individual's bodily fluids, in order to predict or evaluate the metabolism of pharmaceutical compounds, and to better understand the pharmacokinetic profile of a drug. Alternatively, pharmacometabolomics can be applied to measure metabolite levels following the administration of a pharmaceutical compound, in order to monitor the effects of the compound on certain metabolic pathways(pharmacodynamics). This provides detailed mapping of drug effects on metabolism and the pathways that are implicated in mechanism of variation of response to treatment. In addition, the metabolic profile of an individual at baseline (metabotype) provides information about how individuals respond to treatment and highlights heterogeneity within a disease state. All three approaches require the quantification of metabolites found in bodily fluids and tissue, such as blood or urine, and can be used in the assessment of pharmaceutical treatment options for numerous disease states.
Selective serotonin reuptake inhibitors, or serotonin-specific re-uptake inhibitor (SSRIs), are a class of chemical compounds that have contributed to the major advances as antidepressants where they have revolutionised the treatment of depression and other psychiatric disorders. The SSRIs are therapeutically useful in the treatment of panic disorder (PD), posttraumatic stress disorder (PTSD), social anxiety disorder, obsessive-compulsive disorder (OCD), premenstrual dysphoric disorder (PMDD) and anorexia. There is also clinical evidence of SSRIs efficiency in the treatment of the negative symptoms of schizophrenia and their ability to prevent cardiovascular diseases.
Dehydronorketamine (DHNK), or 5,6-dehydronorketamine, is a minor metabolite of ketamine which is formed by dehydrogenation of its metabolite norketamine. Though originally considered to be inactive, DHNK has been found to act as a potent and selective negative allosteric modulator of the α7-nicotinic acetylcholine receptor (IC50 = 55 nM). For this reason, similarly to hydroxynorketamine (HNK), it has been hypothesized that DHNK may have the capacity to produce rapid antidepressant effects. However, unlike ketamine, norketamine, and HNK, DHNK has been found to be inactive in the forced swim test (FST) in mice at doses up to 50 mg/kg. DHNK is inactive at the α3β4-nicotinic acetylcholine receptor (IC50 > 100 μM) and is only very weakly active at the NMDA receptor (Ki = 38.95 μM for (S)-(+)-DHNK). It can be detected 7–10 days after a modest dose of ketamine, and because of this, is useful in drug detection assays.
The word "chiral switch" was introduced by Agranat and Caner in 1999. Chiral switches are chiral drugs that are already approved as racemates but that have been re-developed as single enantiomers. The term chiral switching has been coined to describe the development of single enantiomers from racemate drugs. For example, levofloxacin is a chiral switch of racemic ofloxacin. The essential principle of a chiral switch is that there is a change in the status of chirality. In general, the term chiral switch is preferred over racemic switch because the switch is usually happening from a racemic drug to the corresponding single enantiomer(s). It is important to understand that chiral switches are treated as a selection invention. A selection invention is an invention that selects a group of new members from a previously known class on the basis of superior properties. To express the pharmacological activities of each of the chiral twins of a racemic drug two technical terms have been coined eutomer and distomer. The member of the chiral twin that has greater physiological activity is referred to as the eutomer and the other one with lesser activity is referred to as distomer. The eutomer/distomer ratio is called the eudisimic ratio and reflects the degree of enantioselectivity of the biological activity.
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