5-HT1A Receptor

F13640 (befiradol) is a novel 5-HT(1A) receptor agonist with exceptional selectivity vs. other receptors and binding sites[1]. F13640 activates both 5-HT(1A) autoreceptors and postsynaptic 5-HT(1A) receptors in prefrontal cortex with a similar potency. Both activities are likely involved in the analgesic properties of the compound.

Befiradol (F13640; NLX-112) raises the discharge rate of 80% of mPFC pyramidal neurons in the same dose range (ED50=0.62 μg/kg, iv) and decreases the activity of dorsal raphe serotonergic neurons at 0.2-18.2 μg/kg, iv (cumulative doses; ED50=0.69 μg/kg, iv). Subsequent injection of the 5-HT1A receptor antagonist (±)WAY100635 reverses both effects. Befiradol (F13640; NLX-112) (0.04 -0.63 mg/kg, ip) dose-dependently reduces extracellular 5-HT in the mPFC and hippocampal regions in microdialysis experiments. Similarly, Befiradol (F13640; NLX-112) (0.01-2.5 mg/kg, ip) raises extracellular DA in mPFC in a dose-dependent manner. a result reliant on the mPFC's postsynaptic 5-HT1A receptors being activated. In a concentration-dependent manner, local perfusion of Befiradol in mPFC (1-1,000 μM) likewise raises extracellular DA. Befiradol's local and systemic effects can be avoided by administering (±)WAY100635 beforehand[1].

Rats were anaesthetized with chloral hydrate (400–500 mg kg−1, i.p.) or isoflurane. A guide cannula with a dummy probe was stereotaxically implanted into the mPFC, stereotaxic coordinates: AP +3.0 mm, L +0.8 mm, DV −1.7 mm, or the hippocampus: AP −4.8 mm, L +4.6 mm, DV −4.6 mm, from bregma and skull surface. Following surgery and recovery from anesthesia, animals were returned to their home cages. At the end of the day, each rat was placed in a microdialysis cage. On the following day, the dummy probe was replaced by a microdialysis probe (3 mm length, 0.5 mm diameter; CMA, Microdialysis AB). The probe was continuously perfused (1.1 μl min−1) with artificial CSF (aCSF) containing 1 μM citalopram for the measure of 5-HT. At least 2 h after probe insertion, samples were collected every 20 min with the first four samples used for baseline. For the experiment with systemic administration of the compounds, saline or (±)WAY100635 were injected s.c., followed, 40 min later, by i.p. administration of saline or F13640. For the experiments with local perfusion, saline was injected s.c. and 40 min later, F13640 was added to the perfusion medium for the concentration–response experiment. For the antagonism, (±)WAY100635 (or aCSF) was delivered through the dialysis probe and 40 min later, F13640 was added to the perfusion medium. Samples were collected for 140 min after administration or beginning of the perfusion of the agonist. At the end of the experiment, rats were killed by anesthetic overdose (pentobarbital 160 mg kg−1, i.p.) and the brain was removed, frozen and cut in a cryomicrotome (Jung Frigocut 2800) to verify the placement of the probe.[1]

NLX-112 (F13640, befiradol) exhibits nanomolar affinity, high selectivity, and complete agonist potency for the 5-HT1A receptor. NLX-112 has demonstrated efficacy in rat, marmoset, and rhesus monkey models of levodopa-induced dyskinesia (LID) in Parkinson's disease and showed clinical efficacy in a Phase IIa proof-of-concept study for this indication. This study investigated the pharmacodynamics, pharmacokinetics (PK), and 5-HT1A receptor occupancy in the brain of NLX-112 in rats, as well as the PK characteristics in the presence and absence of levodopa. Within the tested dose range (0.04, 0.16, and 0.63 mg/kg, intraperitoneal injection), total and free NLX-112 exposures in plasma, cerebrospinal fluid, and striatal extracellular fluid were dose-proportional. Exposure to NLX-112 increases rapidly (Tmax 0.25–0.5 h), and its half-life in the brain is approximately three times that in plasma (1.1 h and 3.6 h, respectively). At a previously demonstrated pharmacologically relevant dose of 0.16 mg/kg intraperitoneally, which induces anti-levodopa-induced dyskinesia (LID) in Parkinson's disease rats, NLX-112 concentrations in the brain ranged from 51–63 ng/g over 0.15 to 1 hour. In miniature PET imaging experiments, NLX-112 showed a dose-dependent reduction in 18F-F13640 (i.e., 18F-NLX-112)-labeled 5-HT1A receptors in the cingulate gyrus and striatum (areas associated with motor control and emotion), with labeling almost completely inhibited at a dose of 0.63 mg/kg intraperitoneally. Co-administration of levodopa (6 mg/kg subcutaneously, the dose used to induce levodopa-induced dyskinesia in Parkinson's disease rats) with NLX-112 (0.16 mg/kg intraperitoneally) did not alter the pharmacokinetic parameters of either NLX-112 or levodopa in rat plasma and brain tissue. This study demonstrates that the pharmacokinetic profile of NLX-112 meets the "drug-ready" parameters for its central nervous system indication, and the results provide brain concentration and 5-HT1A receptor binding parameters related to the compound's anti-dyskinesia activity. https://pubmed.ncbi.nlm.nih.gov/39096379/

[1]. In vivo electrophysiological and neurochemical effects of the selective 5-HT1A receptor agonist, F13640, at pre- and postsynaptic 5-HT1A receptors in the rat. Psychopharmacology (Berl). 2012 May;221(2):261-72.

Reason: F13640 (befilradol) is a novel 5-HT(1A) receptor agonist with excellent selectivity for other receptors and binding sites. The drug has shown analgesic activity in animal models and is currently being developed for human use. [1] Objective: Given that the serotonergic system may play a dual role in pain, namely by modulating ascending spinal cord signals and emotional processing in the cortical limbic region, we investigated the in vivo activity of F13640 in cell-somatic dendritic autoreceptors and postsynaptic 5-HT(1A) heteroreceptors in the medial prefrontal cortex (mPFC). [1] Methods: In vivo single-cell recording and intracerebral microdialysis in rats. [1] Results: F13640 reduced the activity of dorsal raphe nucleus serotonergic neurons at intravenous doses of 0.2–18.2 μg kg(-1) (cumulative dose; ED(50) = 0.69 μg kg(-1), intravenous) and increased the firing rate of 80% of mPFC pyramidal neurons. Within the same dose range (ED50 = 0.62 μg kg⁻¹, intravenous), F13640 also affected neurons. Subsequent administration of the 5-HT1A receptor antagonist (±)WAY100635 reversed both effects. Microdialysis studies showed that F13640 (0.04–0.63 mg kg⁻¹, intraperitoneal) dose-dependently reduced extracellular 5-HT levels in the hippocampus and medial prefrontal cortex (mPFC). Similarly, F13640 (0.01–2.5 mg kg⁻¹, intraperitoneal) dose-dependently increased extracellular dopamine (DA) levels in the mPFC, an effect dependent on activation of postsynaptic 5-HT1A receptors in the mPFC. Local perfusion of F13640 (1–1000 μM) into the mPFC also increased extracellular DA levels in a concentration-dependent manner. Pre-administration of (±)WAY100635 blocked the systemic and local effects of F13640. [1] Conclusion: These results suggest that, following systemic administration, F13640 can activate 5-HT(1A) autoreceptors and postsynaptic 5-HT(1A) receptors in the prefrontal cortex with similar potency. Both of these activities may be related to the analgesic properties of the compound.

C20H23CL2F2N3O

430.31892991066

429.118

2436760-81-3

Befiradol;208110-64-9

135397148

Typically exists as white to off-white solids at room temperature

2

5

5

28

502

0

MEFWJLIGVNWMAB-UHFFFAOYSA-N

InChI=1S/C20H22ClF2N3O.ClH/c1-14-2-4-16(25-11-14)12-24-13-20(23)6-8-26(9-7-20)19(27)15-3-5-18(22)17(21)10-15;/h2-5,10-11,24H,6-9,12-13H2,1H3;1H

(3-chloro-4-fluorophenyl)-[4-fluoro-4-[[(5-methylpyridin-2-yl)methylamino]methyl]piperidin-1-yl]methanone;hydrochloride

Befiradol hydrochloride; Befiradol (hydrochloride); Befiradol hydrochloride (208110-64-9 free base); NLX-112 hydrochloride; 2436760-81-3; F 13640 hydrochloride; F 13640 (hydrochloride)

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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 (290.48 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (4.83 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 (4.83 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 (4.83 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.)