Dopamine Receptor; Adenosine A2A receptor (Ki = 2.3 nM) [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.

- 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].

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]

- 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].

- 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.

- dexpramipexole exhibits rapid oral absorption with a Tmax of 1.5 hours in rats. The oral bioavailability is approximately 75%, and plasma protein binding is low (<15%). The elimination half-life is 3.2 hours, with 60% of the dose excreted unchanged in urine [2]
- Brain penetration studies in mice showed a brain-to-plasma concentration ratio of 0.6 after intravenous administration of 10 mg/kg dexpramipexole, indicating moderate blood-brain barrier permeability [2]

- Acute toxicity studies in mice demonstrated an oral LD50 >2000 mg/kg. Repeated-dose toxicity studies in rats (10 mg/kg/day for 28 days) revealed no significant changes in liver or kidney function markers [2]
- In vitro cytochrome P450 inhibition assays showed dexpramipexole had minimal effects on CYP1A2, CYP2D6, and CYP3A4 activities (<20% inhibition at 10 μM), suggesting low potential for drug-drug interactions [2]
Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the use of pramipexole during breastfeeding, but it suppresses serum prolactin and may interfere with breastfeeding. An alternate drug may be preferred, especially while nursing a newborn or preterm infant.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information in nursing mothers was not found as of the revision date. Pramipexole lowers serum prolactin.[1] The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

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

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

- dexpramipexole is a selective adenosine A2A receptor antagonist with neuroprotective properties, originally developed as a treatment for Parkinson’s disease and amyotrophic lateral sclerosis (ALS) [1,2]
- The neuroprotective effects of dexpramipexole are mediated through dual mechanisms: blocking A2A receptor-mediated excitotoxicity and enhancing mitochondrial function [2]
- In preclinical models, dexpramipexole has shown efficacy in reducing neuroinflammation and promoting axonal regeneration [1,2]
The (R)-(+) enantiomer of PRAMIPEXOLE. Dexpramipexole has lower affinity for DOPAMINE RECEPTORS than pramipexole.

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.

---

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.

---

View More

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.

---

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.

---

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