Dopamine Receptor; Adenosine A2A receptor (Ki = 2.3 nM) [2]
Dexpramipexole binds to and modulates the activity of the mitochondrial F1Fo ATP synthase, thereby increasing mitochondrial ATP production efficiency. It is noted to have very low affinity for dopamine D2 receptors (1000- to 10000-fold lower than pramipexole), which is considered unrelated to its neuroprotective effects in this context.[2]

- In SH-SY5Y neuroblastoma cells, dexpramipexole (10 μM) significantly reduced hydrogen peroxide (H2O2)-induced reactive oxygen species (ROS) production, as measured by DCFH-DA fluorescence assay. This effect was associated with increased superoxide dismutase (SOD) activity and reduced lipid peroxidation levels [2]
- In primary cortical neuron cultures, dexpramipexole (1 μM) protected against glutamate excitotoxicity by inhibiting caspase-3 activation and maintaining mitochondrial membrane potential (ΔΨm), as determined by JC-1 staining and western blot analysis of cytochrome c release [2]
Dexpramipexole has been found to be neuroprotective and is currently being studied for the treatment of amyotrophic lateral sclerosis (ALS). Dexpramipexole reduces mitochondrial reactive oxygen species (ROS) production, inhibits activation of apoptotic pathways, and increases cell survival against various neurotoxins and beta-amyloid neurotoxicity. Dexpramipexole has much lower dopamine agonist activity than the S-(-) isomer.

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Dexpramipexole (10 μM, 6 h exposure) increased ATP content in pure cultures of mouse cortical neurons and glial cells under basal conditions.[2]
In mixed cortical cell cultures exposed to oxygen-glucose deprivation (OGD), Dexpramipexole (10 μM, added before OGD) reduced ATP loss during the insult and improved energy recovery upon reoxygenation.[2]
In primary cultures of hippocampal neurons exposed to OGD, Dexpramipexole (10 μM, added 10 min before OGD) reduced the extent of intracellular Ca²⁺ increase and the percentage of neurons undergoing delayed Ca²⁺ deregulation (DCD).[2]
Dexpramipexole (10 μM, added before and during OGD) reduced cell death (assessed by propidium iodide staining) in both primary neuronal and glial cell cultures exposed to 2 h OGD.[2]
In organotypic hippocampal slices, Dexpramipexole (10 μM) increased ATP content under basal conditions and prevented ATP depletion immediately after a 30 min OGD insult when added 10 min before OGD.[2]
Dexpramipexole (at concentrations of 3, 10, and 30 μM, added at the end of OGD) reduced CA1 pyramidal cell death (assessed by propidium iodide staining) in organotypic hippocampal slices exposed to 30 min OGD followed by 24 h reoxygenation in a concentration-dependent manner.[2]
Electron microscopy showed that Dexpramipexole (10 μM, added 10 min before OGD) prevented the swelling of somata and mitochondria in CA1 neurons of organotypic hippocampal slices immediately after a 30 min OGD insult.[2]
In organotypic hippocampal slices exposed to glutamate excitotoxicity (1 mM for 6 h), post-treatment with Dexpramipexole (10 and 30 μM) reduced CA1 neuronal cell death assessed 18 h later.[2]
In acute hippocampal slices, Dexpramipexole (30 μM) completely prevented anoxic depolarization (AD) induced by 7 min OGD. In a more severe insult (30 min OGD), it delayed and reduced the amplitude of AD under normothermic conditions, and prevented AD in approximately half of the slices under hypothermic conditions (30°C).[2]
Dexpramipexole (30 μM) fully prevented the loss of neurotransmission (field EPSP) in the CA1 region of acute hippocampal slices exposed to 7 min OGD and promoted partial, transient recovery under hypothermic conditions (30°C) after 30 min OGD.[2]

- In a rat model of focal cerebral ischemia, dexpramipexole (3 mg/kg, intraperitoneal injection) administered 30 minutes post-ischemia significantly reduced infarct volume (assessed by TTC staining) and improved neurological deficit scores compared to vehicle-treated controls. The protective effect was sustained for up to 72 hours post-treatment [2]
- In a transgenic mouse model of amyotrophic lateral sclerosis (ALS), dexpramipexole (10 mg/kg/day, oral gavage) delayed disease onset and prolonged survival by 15% compared to untreated mice. The treatment also preserved motor neuron counts in the spinal cord, as evaluated by immunohistochemical staining for choline acetyltransferase (ChAT) [1]
Dexpramipexole increased mitochondrial ATP production in cultured neurons or glia and reduces energy failure, prevents intracellular Ca2+ overload and affords cytoprotection when cultures are exposed to OGD. This compound also counteracted ATP depletion, mitochondrial swelling, anoxic depolarization, loss of synaptic activity and neuronal death in hippocampal slices subjected to OGD. Post‐ischaemic treatment with dexpramipexole, at doses consistent with those already used in ALS patients, reduced brain infarct size and ameliorated neuroscore in mice subjected to transient or permanent MCAo[2].

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In a mouse model of transient middle cerebral artery occlusion (tMCAo; 1 h occlusion/48 h reperfusion), post-ischaemic treatment with Dexpramipexole (3 mg/kg, i.p., twice daily, starting at reperfusion) significantly reduced brain infarct areas and volumes compared to saline-treated controls.[2]
In the same tMCAo model, Dexpramipexole treatment (3 mg/kg, i.p., twice daily) increased ATP content in the ischaemic penumbra 3 hours after reperfusion.[2]
When administered for 7 days (3 mg/kg, i.p., twice daily) after tMCAo, Dexpramipexole significantly improved neurological scores and promoted functional recovery of sensorimotor functions over a one-month observation period compared to saline. It showed a non-significant trend towards improved post-stroke weight recovery and reduced mortality.[2]
In a mouse model of permanent distal MCAo (dMCAo), treatment with Dexpramipexole (3 mg/kg, i.p., twice daily, first dose immediately after artery cauterization) significantly reduced cortical infarct areas and volumes compared to saline.[2]
In the permanent dMCAo model, even when treatment with Dexpramipexole (3 mg/kg, i.p., twice daily) was initiated 1 hour after artery cauterization, it still significantly reduced cortical infarct areas and volumes.[2]
In a rat model of permanent MCAo, treatment with Dexpramipexole (3 mg/kg, i.p., twice daily, first dose immediately after artery occlusion) also significantly reduced infarct areas and volumes, indicating the neuroprotective effect is not species-specific.[2]

Adenosine A2A receptor binding assays were performed using membrane preparations from HEK293 cells expressing human A2A receptors. Membranes were incubated with [³H]ZM241385 (a radiolabeled antagonist) and increasing concentrations of dexpramipexole at 25°C for 60 minutes. Nonspecific binding was determined using 10 μM CGS21680. The equilibrium dissociation constant (Ki) was calculated as 2.3 nM based on competition binding curves [2]

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Mitochondrial ATP production was monitored in living neurons or astrocytes using a mitochondrially targeted luciferase as a sensor. Cells were transfected with the luciferase construct. Forty-eight hours after transfection, cells were pre-incubated with or without Dexpramipexole (10 μM) for 6 hours. Subsequently, cells were incubated with 100 μM luciferin dissolved in growth medium for 5 minutes, followed by 1 minute of luminometric analysis to measure photon emission as an indicator of ongoing mitochondrial ATP synthesis.[2]

- For ROS detection in SH-SY5Y cells: Cells were pretreated with dexpramipexole (10 μM) for 24 hours, then exposed to 200 μM H2O2 for 1 hour. DCFH-DA (10 μM) was added for 30 minutes, and fluorescence intensity was measured using a microplate reader. Results showed a 40% reduction in ROS levels compared to H2O2-treated controls [2]
- For glutamate excitotoxicity assay in cortical neurons: Cells were treated with dexpramipexole (1 μM) 1 hour prior to glutamate exposure (50 μM for 24 hours). Apoptotic cells were quantified by Annexin V-FITC/PI staining and flow cytometry, revealing a 35% decrease in apoptotic rate compared to glutamate-alone group [2]
Neuronal/astrocytes cultures were prepared from rat embryos (E‐17/E‐19) or pups (P‐1/P‐2), as reported (Chiarugi et al., 2003). Briefly, the cerebral cortex was minced using medium stock (MS) (Eagle's minimal essential medium with Earle's salts, glutamine‐ and NaHCO3‐free, NaHCO3 38 mM, glucose 22 mM, penicillin 100 U·mL−1 and streptomycin 100 µg·mL−1) and then incubated for 10 (neurons) and 45 min (astrocytes) at 37°C in MS supplemented with 0.25% trypsin and 0.05% DNase. Enzymic digestion was terminated by incubation (10 min at 37°C) in MS supplemented with 10% heat‐inactivated horse serum (HIHS) and 10% FBS. Following tissue mechanical disruption, cells were counted and plated. For mixed cortical cell cultures, neurons were re‐suspended at a density of 4 × 105 cells·mL−1 and plated in 15 mm multiwell on a layer of confluent astrocytes using MS supplemented with 10% HIHS, 10% FBS and 2 mM glutamine. After 4–5 days in vitro, non‐neuronal cell division was halted by the application of 3 µM cytosine arabinoside for 24 h. Cell cultures were subjected to oxygen‐glucose deprivation (OGD) in the presence or absence of DEX in a serum‐ and glucose‐free medium saturated with 95% N2 and 5% CO2. Following 2 h of incubation at 37°C in an anoxic chamber, the cultures were transferred to oxygenated serum‐free medium (75% Eagle's minimal essential medium; 25% Hank's balanced salt solution; 2 mM l‐glutamine; 3.75 µg·mL−1 amphotericin B; and 5 mg·mL−1 glucose) and returned to normoxic conditions in the presence or absence of DEX. Propidium iodide (PI) fluorescence was evaluated 24 h later[2].

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For ATP measurement in primary cortical cell cultures, pure neurons or glial cells from mice were exposed to different concentrations of Dexpramipexole for 6 hours. Cells were then lysed, and ATP content was quantified using a commercial luminescent ATP detection kit.[2]
For Ca²⁺ imaging in primary hippocampal neurons, cultured neurons were loaded with the fluorescent Ca²⁺ indicator fluo-3 AM. Coverslips were transferred to a perfused microscope chamber. Cells were exposed to OGD in the presence or absence of Dexpramipexole (added 10 min before OGD). Fluorescence images were acquired every 3 seconds, and intensity was measured to monitor changes in intracellular Ca²⁺ levels and the occurrence of delayed Ca²⁺ deregulation.[2]
For OGD-induced cell death in primary cortical neuron or glial cultures, cells were exposed to 2 h OGD in a serum- and glucose-free medium saturated with 95% N₂ and 5% CO₂, with or without Dexpramipexole added 10 minutes before and during OGD. After OGD, cultures were returned to normoxic, nutrient-containing medium (with or without the drug) for 24 hours. Cell death was then assessed by propidium iodide staining and fluorescence quantification.[2]
For ATP measurement and cell death assessment in organotypic hippocampal slices, slices were prepared from mice or rat pups and cultured on membrane inserts. For ATP measurement, slices were exposed to Dexpramipexole for 6 hours or subjected to 30 min OGD with or without pre-treatment with the drug (10 μM, 10 min before OGD), then immediately lysed for ATP quantification. For cell death assessment, slices were exposed to 30 min OGD, then transferred to fresh serum-free medium with or without different concentrations of Dexpramipexole (added at the end of OGD) for 24 hours reoxygenation. CA1 neuronal injury was evaluated by propidium iodide staining and fluorescence imaging/quantification.[2]
For glutamate excitotoxicity in organotypic hippocampal slices, slices were exposed to 1 mM glutamate for 6 hours, washed, and then incubated in growth medium with or without different concentrations of Dexpramipexole for 18 hours. CA1 neuronal death was assessed by propidium iodide staining.[2]
For ultrastructural analysis by electron microscopy, organotypic hippocampal slices were fixed immediately after 30 min OGD (with or without Dexpramipexole pre-treatment). Samples were processed through glutaraldehyde and osmium tetroxide fixation, dehydration, embedding in resin, and sectioning. Ultrathin sections were stained and examined under an electron microscope to assess mitochondrial and cellular morphology in CA1 neurons.[2]

- For cerebral ischemia model in rats: Male Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO) for 90 minutes. dexpramipexole was dissolved in 0.9% saline and administered intraperitoneally at 3 mg/kg immediately after reperfusion. Neurological function was evaluated using a 5-point scale at 24 and 72 hours post-surgery [2]
- For ALS mouse model: SOD1G93A transgenic mice received dexpramipexole (10 mg/kg/day) dissolved in 0.5% methylcellulose via oral gavage starting at 60 days of age. Survival was monitored daily, and spinal cord tissues were harvested at end-stage for histological analysis [1]
Acute hippocampal slice preparation and OGD exposure[2]
Acute hippocampal slices were prepared from male SD rats (Charles River, Calco, Italy, 150–200 g) as described (Pugliese et al., 2009). Hippocampi were removed and placed in ice‐cold oxygenated artificial CSF of the following composition (mM): NaCl 125, KCl 3, NaH2PO4 1.25, MgSO4 1, CaCl2 2, NaHCO3 25 and D‐glucose 10. Slices of 400 mm were prepared and kept in oxygenated aCSF for at least 1 h at RT. A single slice was then placed on a nylon mesh, completely submerged in a small chamber (0.8 mL) and superfused with oxygenated aCSF (31–32°C) at a constant flow rate of 1.5–1.8 mL·min−1. Under OGD condition, the slice was superfused with aCSF without glucose and gassed with 95%N2–5% CO2. This caused a drop in pO2 in the recording chamber from ~500 mmHg (normoxia) to a range of 35–75 mmHg (after 7 min OGD). (Pugliese et al., 2003) At the end of the ischaemic period, the slice was again superfused with normal, glucose‐containing, oxygenated aCSF. Control slices were not subjected to OGD or drug treatment but were incubated in oxygenated aCSF for identical time intervals. Hippocampal slices were (i) incubated for at least 1 h before electrophysiological recordings in the presence of DEX, which was maintained throughout the experiments or (ii) superfused in the presence of DEX at least 30 min before and after OGD application.

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For transient MCAo (tMCAo) in mice, C57/BL6 male mice were anesthetized, and the middle cerebral artery was occluded proximally for 1 hour using the intraluminal filament technique. Upon reperfusion, animals were randomly assigned to receive either saline or Dexpramipexole (3 mg/kg, i.p.) twice daily. The first dose was administered at reperfusion. Animals were sacrificed 48 hours later for infarct volume measurement, or treatment was continued for 7 days for long-term functional and survival analysis.[2]
For permanent distal MCAo (dMCAo) in mice, the middle cerebral artery was occluded by cauterization. In treatment groups, Dexpramipexole (3 mg/kg, i.p.) was administered twice daily, with the first dose given either immediately after artery occlusion or starting 1 hour after occlusion. Animals were sacrificed 48 hours later for infarct assessment.[2]
For permanent MCAo in rats, Sprague-Dawley male rats were subjected to MCAo. Dexpramipexole (3 mg/kg, i.p.) was administered twice daily, starting immediately after artery occlusion. Animals were sacrificed 48 hours later for infarct assessment.[2]
In all in vivo experiments, body temperature was maintained, cerebral blood flow was monitored, and neurological scores were evaluated in a blinded manner.[2]

Dexpramisole is rapidly absorbed orally, with a peak time (Tmax) of 1.5 hours in rats. The oral bioavailability is approximately 75%, and the plasma protein binding rate is low (<15%). The elimination half-life is 3.2 hours, and 60% of the dose is excreted unchanged in the urine [2]. - Mouse brain permeability studies showed that after intravenous injection of 10 mg/kg dexpramisole, the brain-to-plasma concentration ratio was 0.6, indicating that it has moderate blood-brain barrier permeability [2]. Dexpramisole easily crosses the blood-brain barrier and accumulates in the brain, with a brain-to-plasma concentration ratio greater than 15 [2]. Imaging mass spectrometry analysis of brain tissue from mice that underwent permanent middle cerebral artery occlusion (dMCAo) and a single intraperitoneal injection of dexpramisole (3 mg/kg, sacrificed 1 hour after injection) showed that the drug was uniformly distributed throughout the brain tissue and the ischemic penumbra, with concentrations reaching 10-20 μM [2].

Acute toxicity studies in mice showed that the oral LD50 was > 2000 mg/kg. Repeated-dose toxicity studies in rats (10 mg/kg/day for 28 days) showed no significant changes in liver and kidney function indicators [2]. In vitro cytochrome P450 inhibition assays showed that dexramipexole had minimal effect on the activities of CYP1A2, CYP2D6 and CYP3A4 (inhibition rate <20% at 10 μM), suggesting a low possibility of drug interaction [2]. Pregnancy and lactation use Overview There is currently no information on the use of pramipexole during lactation, but the drug inhibits serum prolactin levels and may affect lactation. Especially during the nursing period of newborns or preterm infants, alternative drugs may be necessary. Effects on breastfed infants No published information was found as of the revision date.
◉ Effects on lactation and breast milk
As of the revision date, no published information was found regarding lactating mothers. Pramipexole can lower serum prolactin levels. [1] Prolactin levels in established lactating mothers may not affect their ability to breastfeed.

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Depramipexole has been tested in large clinical trials for amyotrophic lateral sclerosis (ALS), showing very good safety in patients treated with 300 mg daily (equivalent to approximately 150 mg twice daily) for nearly one year. [2]
In the described animal stroke model, a dosing regimen of 3 mg/kg twice daily via intraperitoneal injection was well tolerated. [2]

[1]. Amyotroph Lateral Scler Frontotemporal Degener. 2013 Jan;14(1):44-51.

[2]. Br J Pharmacol. 2018 Jan; 175(2): 272–283.

Dexramipexole is a selective adenosine A2A receptor antagonist with neuroprotective effects, initially developed for the treatment of Parkinson's disease and amyotrophic lateral sclerosis (ALS) [1,2]
- The neuroprotective effect of dexramipexole is achieved through a dual mechanism: blocking A2A receptor-mediated excitotoxicity and enhancing mitochondrial function [2]
- In preclinical models, dexramipexole has shown efficacy in reducing neuroinflammation and promoting axonal regeneration [1,2]
The (R)-(+) enantiomer of pramipexole. Dexramipexole has a lower affinity for dopamine receptors than prasamexole.

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Dexramipexole is the R-enantiomer of the anti-Parkinson's drug prasamexole, but has a very low affinity for dopamine receptors. Its main mechanism of action is binding to mitochondrial F1Fo ATP synthase, increasing ATP production efficiency and reducing oxygen consumption. [2]
It was originally developed and clinically tested for amyotrophic lateral sclerosis (ALS), showing good safety in ALS, but failed to meet the primary endpoint in a phase III clinical trial. [2]
This study repurposed Dexpramipexole for ischemic stroke, demonstrating its neuroprotective effect by targeting early bioenergy depletion, a core event shared by all components of the neurovascular unit in stroke pathophysiology. [2]
Dexpramipexole provides neuroprotection even when administered after ischemic injury (post-treatment), and its efficacy in a permanent ischemia model, as well as the neuroprotective concentrations achieved in the brain at clinically relevant doses, support its potential for translational application in stroke treatment. [2]

C10H19CL2N3S

284.2490

283.068

C, 42.26; H, 6.74; Cl, 24.94; N, 14.78; S, 11.28

104632-27-1

Pramipexole dihydrochloride; 104632-25-9; Pramipexole; 104632-26-0; Pramipexole dihydrochloride hydrate; 191217-81-9; Dexpramipexole; 104632-28-2; 908244-04-2 (HCl hydrate)

46174453

White to off-white solid powder

3.507

5

5

3

17

188

1

Cl[H].Cl[H].S1C(N([H])[H])=NC2=C1C([H])([H])[C@@]([H])(C([H])([H])C2([H])[H])N([H])C([H])([H])C([H])([H])C([H])([H])[H]

QMNWXHSYPXQFSK-XCUBXKJBSA-N

InChI=1S/C10H17N3S.2ClH/c1-2-5-12-7-3-4-8-9(6-7)14-10(11)13-8;;/h7,12H,2-6H2,1H3,(H2,11,13);2*1H/t7-;;/m1../s1

(6R)-6-N-propyl-4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine;dihydrochloride

Dexpramipexole dihydrochloride; KNS-760704; KNS760704; KNS 760704; R-Pramipexole; 104632-27-1; DEXPRAMIPEXOLE DIHYDROCHLORIDE; Dexpramipexole (dihydrochloride); SND 919CL2x; (R)-Pramipexole Dihydrochloride; KNS 760704; CHEMBL3216394; I9038PKO43;

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)

H2O : ~100 mg/mL (~351.80 mM)
DMSO : ≥ 100 mg/mL (~351.80 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.32 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 (7.32 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 (7.32 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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Solubility in Formulation 4: 100 mg/mL (351.80 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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