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Other names | R-55667; R55667; Tiserton |
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ECHA InfoCard | 100.163.772 |
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Formula | C27H25F2N3OS |
Molar mass | 477.57 g·mol−1 |
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Ritanserin, also known by its developmental code name R-55667, is a serotonin antagonist medication described as an anxiolytic, antidepressant, antiparkinsonian agent, and antihypertensive agent. [1] [2] [3] It was chiefly investigated as a drug to treat insomnia, especially to enhance sleep quality by significantly increasing slow wave sleep by virtue of potent and concomitant 5HT2a and 5HT2c antagonism [4] [5]
It was never marketed for medical use due to safety problems but is currently used in scientific research.
Some of the safety liabilities that led to its discontinuation for the treatment of insomnia has led to its potential repurposing in the field of oncology. Specifically, ritanserin acts as a potent inhibitor of diacylglycerol kinase alpha (DGKα). As such, it may be used to treat certain types of glioblastoma [6] [7] and melanoma. It has also been used as a reference compound to identify putatively more selective and potent DGKα inhibitors to treat these forms of cancer as well as possibly others. [8]
Additionally, ritanserin blocks c-RAF activation and induces apoptotic cell death of non–small cell lung cancer and small cell lung cancer cells. [9]
Ritanserin acts as a selective 5-HT2A (Ki = 0.45 nM) and 5-HT2C receptor (Ki = 0.71 nM) antagonist. [10] [11] It has relatively low affinity for the H1, D2, α1-adrenergic, and α2-adrenergic receptors (39-, 77-, 107-, and 166-fold lower relative to 5-HT2A, respectively). [11] The affinity of ritanserin for the 5-HT1A receptor is less than 1 μM. [11] In addition to its affinity for the 5-HT2A and 5-HT2C receptors, ritanserin also binds to and antagonizes the 5-HT1D, 5-HT2B, 5-HT5A, 5-HT6, and 5-HT7 receptors. [12]
The atypical antipsychotic risperidone was developed from ritanserin. [13]
Ritanserin is the generic name of the drug and its INN , USAN , and BAN . [2] [1] It is also known by its developmental code name R-55667. [1]
Ritanserin was never approved or marketed for medical use. [14] [15] [16]
Ritanserin was tested in clinical trials for depression, [3] anxiety, schizophrenia, [10] and migraine. [17] It was also found to improve sleep in human volunteers. [16]
Aminothiazole (2-thiazolamine) (1) is condensed with 2-acetylbutyrolactone [517-23-7] (2) under DS-trap until the water has separated. Condensation of this β-keto lactone can be visualized to involve initial attack on the reactive butyrolactone by the primary nitrogen; cyclodehydration of that hypothetical intermediate 3 gives 6-(2-hydroxyethyl)-7-methyl-[1,3]thiazolo[3,2-a]pyrimidin-5-one, CID:82612453 (4). Halogenation of the terminal alcohol with phosphorus oxychloride then yields 6-(2-chloroethyl)- 7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one, [86488-00-8] (5). Alkylation with 4-(bis(4-fluorophenyl)methylene)piperidine, [58113-36-3] (6) would complete the synthesis of ritanserin (7).
Ketanserin, sold under the brand name Sufrexal, is an antihypertensive agent which is used to treat arterial hypertension and vasospastic disorders. It is also used in scientific research as an antiserotonergic agent in the study of the serotonin system; specifically, the 5-HT2 receptor family. The drug is taken by mouth.
Doxepin is a medication belonging to the tricyclic antidepressant (TCA) class of drugs used to treat major depressive disorder, anxiety disorders, chronic hives, and insomnia. For hives it is a less preferred alternative to antihistamines. It has a mild to moderate benefit for sleeping problems. It is used as a cream for itchiness due to atopic dermatitis or lichen simplex chronicus.
Trazodone, sold under many brand names, is an antidepressant medication, used to treat major depressive disorder, anxiety disorders, and insomnia. It is a phenylpiperazine compound of the serotonin antagonist and reuptake inhibitor (SARI) class. The medication is taken orally.
Lisuride, sold under the brand name Dopergin among others, is a monoaminergic medication of the ergoline class which is used in the treatment of Parkinson's disease, migraine, and high prolactin levels. It is taken by mouth.
The 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor (GPCR). The 5-HT2A receptor is a cell surface receptor, but has several intracellular locations.
2C (2C-x) is a general name for the family of psychedelic phenethylamines containing methoxy groups on the 2 and 5 positions of a benzene ring. Most of these compounds also carry lipophilic substituents at the 4 position, usually resulting in more potent and more metabolically stable and longer acting compounds. Most of the currently known 2C compounds were first synthesized by Alexander Shulgin in the 1970s and 1980s and published in his book PiHKAL. Shulgin also coined the term 2C, being an acronym for the 2 carbon atoms between the benzene ring and the amino group.
5-Hydroxytryptamine receptor 2B (5-HT2B) also known as serotonin receptor 2B is a protein that in humans is encoded by the HTR2B gene. 5-HT2B is a member of the 5-HT2 receptor family that binds the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Like all 5-HT2 receptors, the 5-HT2B receptor is Gq/G11-protein coupled, leading to downstream activation of phospholipase C.
Setoperone is a compound that is a ligand to the 5-HT2A receptor. It can be radiolabeled with the radioisotope fluorine-18 and used as a radioligand with positron emission tomography (PET). Several research studies have used the radiolabeled setoperone in neuroimaging for the studying neuropsychiatric disorders, such as depression or schizophrenia.
Sarpogrelate is a drug which acts as an antagonist at the 5HT2A and 5-HT2B receptors. It blocks serotonin-induced platelet aggregation, and has applications in the treatment of many diseases including diabetes mellitus, Buerger's disease, Raynaud's disease, coronary artery disease, angina pectoris, and atherosclerosis.
Xylamidine is a drug which acts as an antagonist of the serotonin 5-HT2A and 5-HT2C receptors, and to a lesser extent of the serotonin 5-HT1A receptor. The drug does not cross the blood–brain barrier and hence is peripherally selective, which makes it useful for blocking peripheral serotonergic responses like cardiovascular and gastrointestinal effects, without producing the central effects of 5-HT2A receptor blockade such as sedation, or interfering with the central actions of 5-HT2A receptor agonists.
Fananserin (RP-62203) is a drug which acts as a potent antagonist at both the 5HT2A receptor, and the Dopamine D4 receptor, but without blocking other dopamine receptors such as D2. It has sedative and antipsychotic effects, and has been researched for the treatment of schizophrenia, although efficacy was less than expected and results were disappointing.
Amperozide is an atypical antipsychotic of the diphenylbutylpiperazine class which acts as an antagonist at the 5-HT2A receptor. It does not block dopamine receptors as with most antipsychotic drugs, but does inhibit dopamine release, and alters the firing pattern of dopaminergic neurons. It was investigated for the treatment of schizophrenia in humans, but never adopted clinically. Its main use is instead in veterinary medicine, primarily in intensively farmed pigs, for decreasing aggression and stress and thereby increasing feeding and productivity.
RS-127445 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with around 1000 times selectivity over the closely related 5-HT2A and 5-HT2C receptors. The role of the 5-HT2B receptor in the body is still poorly understood, and RS-127445 has been a useful tool in unravelling the function of the various systems in which this receptor is expressed.
SB-204741 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with around 135x selectivity over the closely related 5-HT2C receptor, and even higher over the 5-HT2A receptor and other targets. It is used in scientific research for investigating the functions of the 5-HT2B receptor.
AL-38022A is an indazole derivative drug which is one of a range of similar drugs developed for scientific research and with some possible clinical applications. It acts as a potent and selective agonist for the 5-HT2 family of serotonin receptors, with highest binding affinity for the 5-HT2C subtype and around four times less affinity for 5-HT2A and 5-HT2B. In drug discrimination tests on animals, it fully substituted for both DOM and 5-MeO-DMT.
Volinanserin (INN) is a highly selective 5-HT2A receptor antagonist that is frequently used in scientific research to investigate the function of the 5-HT2A receptor. It was also tested in clinical trials as a potential antipsychotic, antidepressant, and treatment for insomnia but was never marketed.
Pruvanserin is a selective 5-HT2A receptor antagonist which was under development by Eli Lilly and Company for the treatment of insomnia. It was in phase II clinical trials in 2008 but appears to have been discontinued as it is no longer in the company's development pipeline. In addition to its sleep-improving properties, pruvanserin has also been shown to have antidepressant, anxiolytic, and working memory-enhancing effects in animal studies.
25CN-NBOH is a compound indirectly derived from the phenethylamine series of hallucinogens, which was discovered in 2014 at the University of Copenhagen. This compound is notable as one of the most selective agonist ligands for the 5-HT2A receptor yet discovered, with a pKi of 8.88 at the human 5-HT2A receptor and with 100x selectivity for 5-HT2A over 5-HT2C, and 46x selectivity for 5-HT2A over 5-HT2B. A tritiated version of 25CN-NBOH has also been accessed and used for more detailed investigations of the binding to 5-HT2 receptors and autoradiography.
Ocaperidone is a benzisoxazole antipsychotic. It was initially developed by Janssen, later licensed to French laboratory Neuro3D and then acquired in 2007 by German company Evotec. It was found to be more potent than risperidone in animal studies, but its testing was abandoned in 2010 after unfavorable results in human Phase II trials, as while it was effective at controlling symptoms of schizophrenia, ocaperidone produced an unacceptable amount of extrapyramidal side effects.
SB-200646 is a 5-HT2 receptor antagonist with anxiolytic properties in rats. It was the first 5-HT2 antagonist discovered to exhibit selectivity for the 5-HT2C/2B receptors over the 5-HT2A receptor.