Dopamine reuptake (Ki = 1 nM)[1]
Vanoxerine primarily targets the dopamine transporter (DAT). By binding to DAT, it blocks the reuptake of dopamine from the synaptic cleft back into the presynaptic neuron, leading to a significant increase in extracellular dopamine concentrations. It has a >100-fold lower affinity for the norepinephrine and serotonin transporters, highlighting its high selectivity for DAT. Research also indicates it may have additional mechanisms of action, including antagonist activity at nicotinic acetylcholine receptors (nAChRs).

Vanoxerine diHClide (GBR-12909 diHClide) is a low-fold effective supplement of norepinephrine and serotonin that suppresses the nutrient dopamine (DA) with an IC50 in the low nanomolar range [2]. Another wall mixed ion channel blocker having IKr, INa, and L-type calcium channel action is -12909 dihydrochloride [3].
In vitro, Vanoxerine is a potent inhibitor of dopamine uptake, with IC50 values ranging from 1 to 51 nM. It binds to the dopamine transporter with a Ki of 1 nM. It also blocks Ca²⁺ and Na⁺ currents in a frequency-dependent manner. In addition to its effects on DAT, it has been observed as a potent blocker of the cardiac hERG/IKr potassium channel and the L-type calcium channel, which are likely responsible for its cardiac effects.

Behavioral effects of a dopamine uptake inhibitor, GBR-12909 (GBR), were evaluated by ambulatory activity in mice. The single administration of over 10 mg/kg of GBR, i.p. and p.o., significantly increased the ambulatory activity. The repeated administration of GBR, at only 10 mg/kg, produced a reverse tolerance to its ambulation-increasing effect. However, a cross-reverse tolerance was induced between GBR (10 and 20 mg/kg) and methamphetamine (2 mg/kg) in both directions. Furthermore, 5 mg/kg of GBR significantly enhanced the effects of methamphetamine, cocaine, imipramine, morphine, scopolamine and caffeine. R-THBP, a coenzyme of tyrosine hydroxylase, also enhanced the effect of GBR. In contrast, the ambulation-increasing effect of 10 mg/kg of GBR was markedly reduced by haloperidol, chlorpromazine, tetrabenazine, oxypertine, reserpine and alpha-methyl-p-tyrosine. On the other hand, the effect of GBR was only slightly and/or scarcely modified by apomorphine, caerulein, physostigmine, pilocarpine, N6-(L-2-phenylisopropyl)-adenosine and naloxone. The neurochemical experiment in rats, not in mice, revealed that GBR possessed more dominant action on dopaminergic systems than noradrenergic or serotonergic systems. However, the behavioral characteristics of GBR are similar to those of methamphetamine and cocaine, which possess less selective action than GBR on dopaminergic and noradrenergic systems[2].
In vivo, Vanoxerine possesses anticonvulsant activity in zebrafish and rodent models of generalized epilepsy. Its behavioral effects are similar to those of cocaine, including increased locomotor activity and potential for abuse. In dogs, it was studied for its effects on atrial fibrillation and atrial flutter, where it showed some promise before cardiac safety concerns emerged. Its effects on the dopamine system have made it a key tool for studying the neurobiology of reward, addiction, and movement disorders.

The neurochemical profile of GBR 12909 (1-(2-bis(4-fluorphenyl)-methoxy)-ethyl)-4-(3-phenyl-propyl)pipera zine) was investigated. GBR 12909 was a potent and selective inhibitor of synaptosomal dopamine uptake (KI = 1 nM), with a 20-fold lower affinity for the histamine H1-receptor and a more than 100-fold affinity for the noradrenaline and 5-HT uptake carriers, the dopamine D-1, D-2, 5-HT2, 5-HT1A and alpha 1-receptors and voltage-dependent sodium channels. GBR 12909 (3 microM) was without effect on muscarinic, alpha 2, beta 1 + 2, gamma-aminobutyric acid (GABA) and benzodiazepine receptors, and on choline and GABA uptake carriers. The selective dopamine uptake inhibitory profile of GBR 12909 was confirmed by ex vivo uptake experiments. GBR 12909 inhibited uptake in vitro in a competitive manner as did cocaine and methylphenidate. [3H]GBR 12935 binding was competitively inhibited by GBR 12909 as well as by dopamine, cocaine and methylphenidate. Off-rate analysis of the [3H]GBR 12935 binding excluded the presence of allosteric binding sites on the dopamine carrier complex. Instead, the data favored the notion that GBR 12909 inhibits dopamine uptake by binding to the dopamine binding site on the carrier protein itself, thereby blocking the carrier process. In conclusion, GBR 12909 is a highly selective inhibitor of dopamine uptake, both in vivo and in vitro. At the moment GBR 12909 is the only compound with this neurochemical profile. The selective effect of GBR 12909 on this neuronal system makes it an interesting experimental tool and a potential antidepressant agent[3].
In vitro enzyme/receptor binding (non-cell) assays for Vanoxerine are performed using membrane preparations from cells expressing the dopamine transporter (DAT). These membranes are incubated with a radiolabeled DAT ligand, such as [³H]WIN 35,428, and varying concentrations of Vanoxerine. Binding affinity (Ki) is determined by competitive displacement of the radiolabeled ligand. Dopamine uptake is measured using [³H]dopamine in synaptosomes or DAT-expressing cells to determine the IC50 for uptake inhibition.

In vitro cell-based experiments for Vanoxerine are conducted using cells expressing the dopamine transporter (e.g., HEK-293 or CHO cells). Cells are seeded in multi-well plates and incubated with Vanoxerine at various concentrations. Dopamine uptake is measured by adding [³H]dopamine to the cells and then quantifying the amount of radioactivity taken up. The IC50 value for inhibition of dopamine uptake is calculated from the dose-response curve.

Animal/Disease Models: Male mice (6 weeks old ddY strain) [3]
Doses: 2.5, 5, 10, 20 mg/kg Varnosline hydrochloride (2.5-20 mg/kg; intraperitoneal (ip) injection) Dramatically increases walking activity [ 3].
Route of Administration: intraperitoneal (ip) injection.
Experimental Results: The walking activity of mice increased in a dose-dependent manner, with the maximum increase 30 minutes after administration.
In vivo animal experiments for Vanoxerine have been conducted in rodents to study its effects on behavior, locomotion, and seizure activity. In zebrafish models of epilepsy, the anticonvulsant effects were evaluated. In dog models, atrial fibrillation and flutter were induced, and the effects of Vanoxerine on cardiac rhythm were assessed to explore its antiarrhythmic potential.

Absorption, Distribution and Excretion
In healthy male volunteers (n=14), after oral administration of 25, 75, or 125 mg of vaproxil, the peak plasma concentrations (Cmax) were 17.9, 81.1, and 236.5 nmol/L, respectively, with corresponding areas under the curve (AUC) of 81, 365, and 1116 h·nmol/L. In the same group of subjects, the time to peak concentration (tmax) after oral administration of 25, 75, or 125 mg was 0.91, 0.93, and 1.13 h, respectively. The oral bioavailability of this drug depends on food intake. Compared with fasting individuals, volunteers who consumed low-fat and high-fat meals showed 76% and 255% higher bioavailability of vaproxil, respectively. Vaproxil is primarily excreted in urine, bile, and feces. Vaproxil can cross the blood-brain barrier and is distributed to multiple organs, including adipose tissue, lungs, liver, and gastrointestinal tract. Vanoxil has a large volume of distribution. The oral clearances of vanoxil at daily doses of 25, 75, and 125 mg are 660, 478, and 250 L/h, respectively. Metabolites/Metabolites: In vitro studies have shown that vanoxil is primarily metabolized by CYP3A4. CYP2C8 and CYP2E1 may also be involved in the metabolism of this drug. Selective inhibitors of CYP3A4 may interact with vanoxil. Known metabolites of vanoxil include 4-[3-[4-[2-[bis(4-fluorophenyl)methoxy]ethyl]piperazinyl]propyl]phenol and 1-phenyl-3-[4-[2-(4,4'-difluorophenylmethoxy)ethyl]piperazinyl]-1-propanol.

---

Biological Half-Life
The mean elimination half-life of vanoxiline is 53.5 hours at 75 mg/day and 66 hours at 125 mg/day.
Vanoxerine is well-absorbed and distributes to the CNS due to its lipophilic nature. It has a very long half-life in humans, with a reported terminal half-life of approximately 66 hours at steady state after oral administration. This long half-life, while potentially advantageous for once-daily dosing, also contributed to its safety concerns. Detailed PK parameters, including Cmax and AUC, have been characterized in clinical studies.

Protein Binding
Vanoxil showed 99% plasma protein binding at concentrations of 0.1, 0.4, and 1 μM.
Vanoxerine has significant cardiac ion channel effects, including potent blockade of the hERG channel, which prolongs the QT interval and can lead to life-threatening arrhythmias. This cardiac toxicity led to the termination of Phase III trials for atrial fibrillation. At therapeutic doses, it was well-tolerated in preclinical studies, but the cardiac safety margin was not sufficient for clinical use.

[1]. Rothman RB, et al. Dopamine transport inhibitors based on GBR12909 and benztropine as potential medications to treat cocaine addiction. Biochem Pharmacol. 2008 Jan 1;75(1):2-16.
[2]. Hirate K, et al. Characteristics of the ambulation-increasing effect of GBR-12909, a selective dopamine uptakeinhibitor, in mice. Jpn J Pharmacol. 1991 Apr;55(4):501-11.
[3]. Andersen PH. The dopamine inhibitor GBR 12909: selectivity and molecular mechanism of action. Eur J Pharmacol.

Vanoxerine is an N-alkylpiperazine compound composed of a piperazine ring with 2-bis(4-fluorophenyl)methoxy[2-ethyl] and 3-phenylpropyl groups attached to positions 1 and 4, respectively. It is a potent competitive dopamine uptake inhibitor (Ki = 1 nM inhibition of striatal dopamine uptake). It has an affinity for norepinephrine and serotonin uptake carriers that is more than 100 times lower than that for dopamine. It is also a potent σ receptor ligand (IC50 = 48 nM). It exhibits central activity after systemic administration. It is a dopamine uptake inhibitor. It is an N-alkylpiperazine, organofluorine compound, tertiary amine compound, and ether compound. It is the conjugate base of vanoxerine(2+). Vanoxerine is a highly selective dopamine transporter antagonist. It was synthesized in the late 1970s and developed as a potential treatment for depression. Vanoxerine was later evaluated as a potential treatment for cocaine addiction because it blocks dopamine reuptake at a slower dissociation rate than cocaine. While some studies suggest that vanoxerine is safer than cocaine, others have found at least a moderate risk of abuse. Recently, vanoxerine has been tested as a potential antiarrhythmic and anti-atrial fibrillation drug because it blocks the hKV11.1 (hERG) cardiac potassium channel. Vanoxerine is an investigational drug and has not yet been approved for clinical use.

---

Drug Indications
Vanoxerine has not yet been approved for clinical use.

---

Mechanism of Action
Vanoxerine is a highly selective dopamine transporter antagonist. Because it inhibits dopamine reuptake, it has been thought that vanoxerine may be helpful in treating cocaine addiction. Cocaine increases dopamine levels in the synaptic cleft by binding to and blocking dopamine transporters. Compared to cocaine, varanoxiline has a higher affinity for the dopamine transporter, a slower dissociation rate, and does not possess the stimulant effects of cocaine. Varanoxiline is also used to treat conditions characterized by low dopamine levels, such as Parkinson's disease and depression. Varanoxiline is also a potent hKV11.1 (hERG) cardiac potassium channel blocker. Even at low concentrations, varanoxiline blocks calcium and sodium ion currents without significantly affecting the QT interval, action potential waveform, or transmural repolarization dispersion. Therefore, the antiarrhythmic and antifibrillation properties of varanoxiline have been investigated.

---

Pharmacodynamics
Varanoxiline inhibits dopamine reuptake by binding to and blocking the dopamine transporter. The use of varanoxiline as a potential alternative to cocaine in the treatment of drug addiction has been evaluated. In primates, intravenous administration of vanoxerine reduced cocaine self-administration at a dose of 1 mg/kg and completely eliminated it at a dose of 3 mg/kg. No stimulant effects of cocaine were detected in healthy volunteers (n=8) treated with vanoxerine for two weeks, suggesting a lack of abuse potential. However, other studies have found that vanoxerine has at least moderate human abuse potential. The antiarrhythmic potential of vanoxerine has also been evaluated. A clinical study evaluating the efficacy of vanoxerine in converting atrial fibrillation (AF) or atrial flutter (AFL) to normal sinus rhythm reported that a significant proportion of patients with symptomatic AF/AFL who received 200, 300, and 400 mg of vanoxerine within 24 hours achieved sinus rhythm restoration. In studies evaluating doses ranging from 25 to 300 mg, vanoxerine was considered safe and well-tolerated.
Vanoxerine is also known as GBR-12909 and I-893. It is a research compound used extensively as a tool to study dopamine transporter function and the neurobiology of addiction. Despite its lack of clinical success, it remains a standard reference compound in the field. It is not approved for any clinical use.

C28H34CL2F2N2O

523.4852

522.201

C, 64.24; H, 6.55; Cl, 13.54; F, 7.26; N, 5.35; O, 3.06

67469-78-7

Vanoxerine;67469-69-6

3455

Typically exists as White to off-white solid at room temperature

542.7ºC at 760 mmHg

221 °C

282ºC

6.801

0

5

10

33

498

0

Cl[H].Cl[H].FC1C([H])=C([H])C(=C([H])C=1[H])C([H])(C1C([H])=C([H])C(=C([H])C=1[H])F)OC([H])([H])C([H])([H])N1C([H])([H])C([H])([H])N(C([H])([H])C([H])([H])C([H])([H])C2C([H])=C([H])C([H])=C([H])C=2[H])C([H])([H])C1([H])[H]

MIBSKSYCRFWIRU-UHFFFAOYSA-N

InChI=1S/C28H32F2N2O.2ClH/c29-26-12-8-24(9-13-26)28(25-10-14-27(30)15-11-25)33-22-21-32-19-17-31(18-20-32)16-4-7-23-5-2-1-3-6-23/h1-3,5-6,8-15,28H,4,7,16-22H22*1H

1-(2-[bis(4-Fluorophenyl)methoxy]ethyl)-4-(3-phenylpropyl)piperazine dihydrochloride

Vanoxerine DiHCl; GBR 12909; Vanoxerine dihydrochloride; GBR 12909 dihydrochloride; Vanoxerine hydrochloride; GBR-12909 dihydrochloride; Vanoxeamine; Vanoxerine dihydrochloride(GBR12909); 1-(2-(bis(4-fluorophenyl)methoxy)ethyl)-4-(3-phenylpropyl)piperazine dihydrochloride; GBR-12909; GBR12909.

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 : ~9.4 mg/mL (~17.96 mM)
H2O : ~1 mg/mL (~1.91 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (3.97 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.

---

Solubility in Formulation 2: ≥ 2.08 mg/mL (3.97 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.

---

View More

Solubility in Formulation 3: ≥ 2.08 mg/mL (3.97 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.

---

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