5-HT2A Receptor
Eplivanserin targets two components of the serotonergic system: the serotonin transporter (SERT), which is responsible for serotonin reuptake, and the 5-HT2A receptor, a serotonin receptor subtype. As a selective serotonin reuptake inhibitor, eplivanserin blocks the reuptake of serotonin into presynaptic neurons, increasing synaptic serotonin concentrations. As a 5-HT2A receptor antagonist, the compound blocks the activation of 5-HT2A receptors by serotonin. Eplivanserin has an IC50 of 5.8 nM in rat cortical membrane and a Kd of 1.14 nM for the 5-HT2A receptor, demonstrating its high potency and affinity. The combination of serotonin reuptake inhibition and 5-HT2A receptor antagonism may provide a unique pharmacological profile for the treatment of psychiatric disorders.

Eplivanserin (SR 46349B) has mild inhibitory effects on other 5-HT kinases with IC50 of 0.12 μM (porcine cortical 5-HT1C), 14 μM (rat hippocampus 5-HT1A), and 16 μM (rat stnatum 5-HT1B , Ox) caudate nucleus 5-HT1D). Eplivanserin also inhibits rat cortical epinephrine α1 and α2, rat whole brain histamine H1, Na+ channels, and rat striatum dopamine D1 and D2, with IC50 of 3.4 μM, 1.0 μM, 5.0 μM, and 39 μM correspondingly. , 9 μM and 28 μM, respectively [1].

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Eplivanserin demonstrates potent in vitro activity at both the serotonin transporter and the 5-HT2A receptor. As a 5-HT2A receptor antagonist, the compound has an IC50 of 5.8 nM in rat cortical membrane and a Kd of 1.14 nM, demonstrating high potency and affinity. As a serotonin reuptake inhibitor, the compound blocks the uptake of serotonin into presynaptic neurons. The compound's activity has been characterized in receptor binding and functional assays. Its dual mechanism of action-serotonin reuptake inhibition and 5-HT2A receptor antagonism-makes it a unique pharmacological tool for studying serotonergic signaling. The compound's potency and selectivity have been described in patent literature.

The 5-HT2 receptor binding of [3H]ketanserin is inhibited by eplivanserin halffumarate (SR 46349B), with an ED50 of 0.087 mg/kg following intraperitoneal injection and 0.097 mg/kg following oral dosing in mice [1]. Following repeated cocaine treatment, SR 46349B (0.25–1 mg/kg; i.p.) inhibits the hyperactivity caused by cocaine in rats [2].

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In vivo, eplivanserin has been evaluated in animal models for its effects on serotonin-mediated behaviors. The compound is orally active, making it suitable for convenient dosing regimens in research settings. Its dual mechanism of action-serotonin reuptake inhibition and 5-HT2A receptor antagonism-may provide effects on mood, anxiety, sleep, and other serotonin-modulated functions. Eplivanserin has been studied in preclinical models of psychiatric and neurological disorders. The compound's in vivo activity has been described in patent literature. Its oral bioavailability and pharmacokinetic properties support its use in preclinical studies.

A new potent, selective and p.o. active serotonergic [5-hydroxytryptamine (5-HT2)] receptor antagonist, Eplivanserin (SR-46349) [trans, 4-([3Z)3-(2-dimethylaminoethyl)oxyimino-3(2-flurophenyl++ +)propen-1-yl]phenol hemifumarate) has been characterized by a series of "in vitro" and "in vivo" methods. Based upon binding studies with 5-HT2 receptors in rat brain cortical membranes and blockade of 5-HT-induced contractions in isolated tissues (rabbit thoracic aorta, rat jugular vein, rat caudal artery, rat uterus and guinea pig trachea), Eplivanserin (SR-46349) showed high affinity for 5-HT2 receptors. Furthermore, Eplivanserin (SR-46349) displayed moderate affinity for the 5-HT1C receptor and had no affinity for the other 5-HT1 subclass (5-HT1A, 5-HT1B or 5-HT1D), dopamine (D1 or D2), "alpha" adrenergic (alpha-1 or alpha-2), sodium and calcium channel and histamine (H1) receptors. It did not interact with histamine (H1), alpha-1 adrenergic and 5-HT3 receptors in smooth muscle preparations. No inhibition of the uptake of norepinephrine, dopamine or 5-HT was seen. Based upon blockade of pressor responses to 5-HT in pithed rats and in vivo binding studies in mice, SR 46349B was found to be a potent and p.o. active 5-HT2 receptor antagonist with a relatively long duration of action. Behavioral experiments, including mescaline- and 5-hydroxytryptophan-induced head twitches and learned helplessness, as well as sleep-waking cycle and EEG spectral parameter studies, indicated that SR 46349B has a classical 5-HT2 psychopharmacological antagonist profile.[1]

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In vitro receptor binding assays for eplivanserin involve measuring binding affinity to the 5-HT2A receptor. Membranes from rat cortex or cells expressing recombinant 5-HT2A receptors are incubated with a radiolabeled 5-HT2A ligand (e.g., [3H]-ketanserin) and varying concentrations of the test compound. Bound and free radioligand are separated by filtration, and radioactivity is measured by liquid scintillation counting. Binding affinity (Ki or Kd) is calculated from competition curves using non-linear regression analysis. For serotonin reuptake inhibition assays, synaptosomes or cells expressing the serotonin transporter are incubated with [3H]-serotonin and varying concentrations of the test compound. The uptake of [3H]-serotonin is measured, and IC50 values are calculated. Each concentration is typically tested in duplicate or triplicate.

In vitro cellular assays for eplivanserin are performed using cells expressing the serotonin transporter or 5-HT2A receptors. For serotonin reuptake inhibition assays, cells are incubated with [3H]-serotonin and varying concentrations of the test compound, and the uptake of the radiolabeled serotonin is measured. For 5-HT2A receptor antagonism assays, cells expressing the receptor are treated with serotonin and varying concentrations of the test compound. Receptor activation is measured by calcium mobilization or inositol phosphate accumulation. The compound's ability to inhibit serotonin-stimulated signaling is determined from dose-response curves. Cytotoxicity is assessed in parallel using standard viability assays. IC50 values for receptor antagonism and reuptake inhibition are calculated from dose-response curves.

The 5-HT2AR antagonist Eplivanserin (SR-46349) also blocked cocaine-evoked hyperactivity following repeated cocaine treatment, whereas the other 5-HT2R ligands were ineffective. When any of the 5-HT2R ligands was coadministered with cocaine during the treatment regimen (10 mg/kg/day for 5 days), the development of sensitization was unchanged as measured by the level of cocaine-evoked hyperactivity upon challenge 5 days after termination of the treatment. The present study implies that 5-HT2AR and 5-HT2CR exert oppositional influence upon hyperactivity evoked by acute administration of cocaine; this balance is altered following repeated cocaine administration.

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In vivo animal studies for eplivanserin are conducted using rodent models of psychiatric and neurological disorders. The compound is administered via oral gavage or other routes. Behavioral tests are used to assess the compound's effects on serotonin-mediated behaviors, including tests of anxiety (elevated plus maze, open field), depression (forced swim test, tail suspension test), and sleep (sleep-wake cycle monitoring). Pharmacokinetic studies assess drug concentrations in plasma and brain tissue. The compound's effects on serotonin levels in the brain can be assessed by microdialysis. Animals are monitored for clinical signs and body weight. Efficacy is expressed as the change in behavior or neurotransmitter levels compared to vehicle-treated controls.

Pharmacokinetic properties of eplivanserin have been characterized in preclinical studies. The compound has a molecular formula of C19H21FN2O2 and a molecular weight of 328.39 g/mol. It is orally active, making it suitable for convenient dosing regimens. The compound is soluble in DMSO and other organic solvents. Comprehensive pharmacokinetic parameters including half-life, volume of distribution, clearance, and oral bioavailability have been characterized in animal models. The compound's ability to cross the blood-brain barrier is relevant for its central nervous system effects. Its pharmacokinetic profile supports its use in preclinical studies of serotonergic signaling. Detailed pharmacokinetic data are available in the patent literature.

Eplivanserin is intended for laboratory research use only and has not undergone comprehensive toxicology testing. As a serotonin reuptake inhibitor and 5-HT2A receptor antagonist, the compound would be expected to have effects on mood, behavior, and physiological functions regulated by serotonin. Standard in vitro cytotoxicity assays in cell lines are typically performed alongside efficacy studies to rule out nonspecific toxicity. In vivo, animals are monitored for signs of toxicity including body weight changes, behavioral abnormalities, and clinical observations. Comprehensive toxicological characterization including genotoxicity, cardiotoxicity, and repeated-dose toxicity studies has not been reported in the public domain. The compound is not approved for human use and is strictly intended for research purposes.

[1]. Biochemical and pharmacological properties of SR 46349B, a new potent and selective 5-hydroxytryptamine2 receptor antagonist. J Pharmacol Exp Ther. 1992 Aug;262(2):759-68.

[2]. Contribution of serotonin (5-hydroxytryptamine; 5-HT) 5-HT2 receptor subtypes to the hyperlocomotor effects of cocaine: acute and chronic pharmacological analyses. J Pharmacol Exp Ther. 2004 Sep;310(3):1246-54.

[3]. COMPOSITIONS CONTAINING A SEROTONIN SELECTIVE REUPTAKE INHIBITOR AND A 5-HT2A RECEPTOR ANTAGONIST. WO 2005/002578 A1.

Eplivanserin has been used in trials for the treatment of sleep disorders, insomnia, chronic pain, fibromyalgia, and primary insomnia.

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Drug Indications>
Insomnia
This study compared the roles of serotonin (5-hydroxytryptamine; 5-HT) 5-HT2 receptor subtypes (5-HT2AR, 5-HT2BR, and 5-HT2CR) in acute cocaine-induced hyperactivity in male Wistar rats, and their contributions to the development and expression of motor sensitization following repeated, intermittent cocaine treatment (10 mg/kg/day for 5 days). Pretreatment with the preferred 5-HT2AR agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and the 5-HT2CR antagonist SDZ SER-082 [(+)-cis-4,5,7a,8,9,10,11,11a-octahydro-7H-10-methylindolo(1,7-BC)(2,6)naphthylidine fumarate] significantly enhanced cocaine-induced hyperactivity. The 5-HT2AR antagonist SR 46349B [1(Z)-[2-(dimethylamino)ethoxyimino]-1(2-fluorophenyl)-3-(4-hydroxyphenyl)-2(E)-propene] and the preferred 5-HT2CR agonist MK 212 [6-chloro-2-(1-piperazinyl)pyrazine hydrochloride] (2 mg/kg) significantly attenuated cocaine-induced acute ADHD; however, lower doses of MK 212 (0.3 mg/kg) enhanced cocaine-induced ADHD. The 5-HT2BR agonist BW 723C86 (1-[5-(2-thiophenemethoxy)-1H-3-indolyl]propyl-2-amine hydrochloride) and the 5-HT2BR antagonist SB 204741 [N-(1-methyl-5-indolyl)-N'-(3-methyl-5-isothiazolyl)urea] had no effect on cocaine-induced hyperactivity. Hyperactivity increased two-fold upon re-exposure to cocaine after repeated cocaine treatment alone, 5 days after cessation of cocaine treatment. The 5-HT2AR antagonist SR 46349B also blocked hyperactivity induced by repeated cocaine treatment, while other 5-HT2R ligands were ineffective. During the treatment regimen (10 mg/kg/day for 5 days), if any 5-HT2R ligand was administered concurrently with cocaine, the degree of hyperactivity induced by cocaine was not changed after a second administration of cocaine 5 days after the end of treatment, indicating that the development of sensitization was not altered. This study shows that 5-HT2AR and 5-HT2CR have an antagonistic effect on hyperactivity induced by acute cocaine administration; this balance is altered after repeated administration of cocaine. [2]

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Eplivanserin (SR-46349) is a selective serotonin reuptake inhibitor and 5-HT2A receptor antagonist. It has an IC50 of 5.8 nM in rat cortical membrane and a Kd of 1.14 nM for the 5-HT2A receptor. The compound has a molecular formula of C19H21FN2O2 and a molecular weight of 328.39 g/mol. Eplivanserin is extracted from patent WO 2005/002578 A1. By combining serotonin reuptake inhibition with 5-HT2A receptor antagonism, eplivanserin modulates serotonergic signaling through multiple mechanisms. The compound has been investigated for potential applications in psychiatric and neurological disorders. Eplivanserin has not entered clinical trials and has not received regulatory approval for any indication. It is available from research chemical suppliers for non-clinical research purposes only. Eplivanserin is a valuable research tool for studying serotonergic signaling and developing new therapies for psychiatric disorders.

C19H21FN2O2

328.38

328.158

C, 69.49; H, 6.45; F, 5.79; N, 8.53; O, 9.74

130581-13-4

Eplivanserin hemifumarate;130580-02-8;Eplivanserin;130579-75-8

135515430

Off-white to pink solid powder

4.1

1

5

7

24

418

0

CN(C)CCON=C(C=CC1=CC=C(C=C1)O)C2=CC=CC=C2F

VAIOZOCLKVMIMN-FOUXOUMPSA-N

InChI=1S/C19H21FN2O2/c1-22(2)13-14-24-21-19(17-5-3-4-6-18(17)20)12-9-15-7-10-16(23)11-8-15/h3-12,23H,13-14H2,1-2H3/b12-9+,21-19+

4-[(E,3E)-3-[2-(dimethylamino)ethoxyimino]-3-(2-fluorophenyl)prop-1-enyl]phenol

Eplivanserin; 130579-75-8; SR-46349; SR46349; 3CO94WO6DJ; 130581-13-4; (E)-1-(2-fluorophenyl)-3-(4-hydroxyphenyl)-2-propen-1-one O-[2-(dimethylamino)ethyl]oxime; 4-[(E,3Z)-3-[2-(dimethylamino)ethoxyimino]-3-(2-fluorophenyl)prop-1-enyl]phenol;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product is not stable in solution, please use freshly prepared working solution for optimal results.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~125 mg/mL (~380.66 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (6.33 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (6.33 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (6.33 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)