| Size | Price | Stock | Qty |
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| 5mg |
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| 10mg |
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| 25mg | |||
| 50mg | |||
| Other Sizes |
Purity: ≥98%
| Targets |
The specific targets of (R)-Oxiracetam are not fully elucidated, but as a member of the racetam family, its action is believed to involve multiple pathways in the central nervous system. These compounds primarily act through modulation of glutamatergic (AMPA receptor) and cholinergic neurotransmission. Compared to S-oxiracetam, (R)-oxiracetam exhibits weaker positive allosteric modulation of AMPA receptors, which may contribute to its relatively weaker neuroprotective and cognitive-enhancing effects. No interconversion between the two enantiomers has been observed, suggesting that the differences in their mechanisms of action may stem from chiral structure-dependent receptor binding selectivity.
Target: The exact molecular target of (R)-oxiracetam is not fully elucidated, but racetams are known to modulate glutamatergic (particularly AMPA receptor) and cholinergic neurotransmission. (R)-Oxiracetam acts as a weak positive allosteric modulator of AMPA receptors, enhancing glutamate-induced currents with lower efficacy than its S-counterpart. It also may affect nicotinic acetylcholine receptors and brain-derived neurotrophic factor (BDNF) pathways. Its binding affinity to AMPA receptors is significantly lower than that of S-oxiracetam. |
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| ln Vitro |
(R)-Oxiracetam exhibits significantly weaker activity in in vitro studies compared to its S-enantiomer. Research has shown that in an HT22 hippocampal cell model of indirect toxicity mediated by Aβ-treated BV2 cell-conditioned medium, (R)-oxiracetam demonstrated only minimal neuroprotective effects, while (S)-oxiracetam showed significant protective effects. In cytotoxicity assessments, neither enantiomer exhibited明显的 cytotoxic effects at the tested concentrations. These results suggest that the in vitro neuroprotective activity of oxiracetam is primarily derived from the S-enantiomer, with limited contribution from the R-enantiomer.
In Vitro Activity: In HT22 hippocampal cell models using Aβ-treated BV2-conditioned medium to induce neurotoxicity, (R)-oxiracetam shows minimal neuroprotective effects compared to S-oxiracetam. Neither enantiomer exhibits cytotoxicity at tested concentrations (up to 100 μM). Electrophysiological studies on AMPA receptors expressed in Xenopus oocytes show that (R)-oxiracetam potentiates AMPA-induced currents with EC50 in the millimolar range, while S-oxiracetam is more potent. It does not significantly affect NMDA or kainate receptors. |
| ln Vivo |
Oxiracetam has demonstrated cognitive-improving effects in animal models, but data on (R)-oxiracetam alone are limited as most studies have utilized the racemic mixture. In BALB/c mice, oxiracetam (50 mg/kg, ip) improved avoidance behavior; 100 mg/kg reduced scopolamine-induced amnestic effects and decreased acetylcholine levels in the cortex and hippocampus; and 30 mg/kg pretreatment prevented trimethyltin-induced social cognitive deficits in rats. Pharmacokinetic studies revealed that after oral administration of 200 mg/kg, plasma concentrations of S-oxiracetam at 1, 1.5, and 2 hours were significantly higher than those of R-oxiracetam (p < 0.05), and the AUC0-∞ and Cmax were also significantly greater, suggesting poorer absorption of R-oxiracetam.
In Vivo Activity: In behavioral studies, racemic oxiracetam (50 mg/kg i.p.) improves avoidance acquisition in mice; (R)-oxiracetam alone has not been extensively tested in vivo due to its weaker activity. Oxiracetam (100 mg/kg) reverses scopolamine-induced amnesia and acetylcholine depletion in cortex and hippocampus. However, the R-enantiomer's contribution is minimal; most in vivo effects are attributed to the S-form. No dedicated in vivo efficacy studies for the isolated R-enantiomer are available in public literature. |
| Enzyme Assay |
Cell-free enzyme/receptor binding assays for (R)-Oxiracetam primarily reference established protocols for racemic oxiracetam or S-oxiracetam. A typical protocol includes: 1) Prepare synaptic membranes rich in AMPA receptors or cell membranes expressing recombinant AMPA receptors; 2) Incubate radiolabeled ligand (e.g., [³H]-AMPA) with varying concentrations of (R)-Oxiracetam (0.1-100 μmol/L) in binding buffer containing 50 mM Tris-HCl (pH 7.4) for 60 minutes at room temperature; 3) Terminate the reaction by rapid filtration and measure membrane-bound radioactivity using a liquid scintillation counter; 4) Calculate inhibition rates at each concentration and fit competition binding curves to evaluate the modulatory effect of (R)-Oxiracetam on ligand binding.
In Vitro Enzyme/Receptor Binding Protocol: Receptor binding assays for racetams typically use radioligands such as [3H]AMPA for AMPA receptors. Membrane preparations from rat brain cortex or cells expressing recombinant AMPA receptors are incubated with varying concentrations of (R)-oxiracetam and a fixed concentration of radioligand. Nonspecific binding is determined with excess unlabeled ligand. Binding affinity (Ki) is calculated from competition curves. For AMPA potentiation, two-electrode voltage-clamp in Xenopus oocytes is used to measure current enhancement. |
| Cell Assay |
The in vitro cell assay protocol for (R)-Oxiracetam is as follows: 1) Seed target cells (e.g., HT22 hippocampal neuronal cells or SH-SY5Y cells) in culture plates and culture to appropriate density at 37°C with 5% CO₂; 2) Prepare (R)-Oxiracetam working solutions, typically ranging from 1-100 μmol/L; 3) Add (R)-Oxiracetam to treatment groups and equal volume of vehicle to control groups, incubate for 24-48 hours; 4) For neuroprotection assessment, expose cells to injury conditions (e.g., Aβ-treated conditioned medium, glutamate, or oxygen-glucose deprivation) following drug treatment; 5) Assess cell viability using MTT or CCK-8 assays; 6) Measure apoptosis rate using flow cytometry or TUNEL staining.
In Vitro Cell-Based Assay Protocol: HT22 hippocampal neuronal cells are cultured in DMEM. For neurotoxicity model, cells are exposed to conditioned medium from Aβ-treated BV2 microglia to induce oxidative stress. (R)-Oxiracetam is added at 1-100 μM for 24 h. Cell viability is assessed by MTT or LDH release. For receptor functional assays, HEK293 cells expressing AMPA receptors are loaded with calcium dye and stimulated with glutamate in presence of compound; intracellular calcium is measured fluorometrically. Cytotoxicity is evaluated by trypan blue exclusion. |
| Animal Protocol |
The in vivo animal assay protocol for (R)-Oxiracetam is as follows: 1) Use adult male SD rats or BALB/c mice, randomly divided into model, vehicle control, oxiracetam treatment, and (R)-oxiracetam treatment groups (e.g., 200 mg/kg), with at least 10 animals per group; 2) Administration routes: oral gavage or intraperitoneal injection, typically single dose for pharmacokinetic studies or consecutive dosing for 5-14 days for pharmacodynamic evaluation; 3) Collect plasma samples at multiple time points post-administration (e.g., 0.5, 1, 2, 4, 6, 8, 12, 24 hours); 4) Quantify (R)-oxiracetam concentrations in plasma, urine, and feces using chiral UPLC-MS/MS methods; 5) Assess cognitive function changes using Morris water maze, step-down test, or passive avoidance test; 6) Euthanize animals after experiments and collect brain tissue for bioanalysis.
In Vivo Animal Assay Protocol: For racemic oxiracetam, BALB/c mice receive 50 mg/kg i.p. 30 min before avoidance training. For scopolamine model, mice get 100 mg/kg i.p. and scopolamine (1 mg/kg) before testing; acetylcholine levels in cortex and hippocampus are measured by HPLC. For the R-enantiomer specifically, no published protocols exist. In general, behavioral tests (passive avoidance, Morris water maze) are used, but (R)-oxiracetam has not been tested alone. |
| ADME/Pharmacokinetics |
The pharmacokinetic profile of (R)-Oxiracetam in rats differs significantly from that of S-oxiracetam. Following oral administration of 200 mg/kg, plasma concentrations of (R)-oxiracetam at early time points (1, 1.5, and 2 hours) were significantly lower than those of S-oxiracetam, and the AUC0-∞ and Cmax were also significantly smaller, indicating poorer absorption of (R)-oxiracetam. The two enantiomers do not undergo chiral interconversion in rats, and there are no stereoselective differences in plasma protein binding rates. In humans receiving 4 g oxiracetam injection, no enantiomer interconversion was observed; oxiracetam is primarily excreted unchanged via urine, with a cumulative excretion rate of 85.92% within 24 hours. These results suggest that the bioavailability of (R)-oxiracetam is lower than that of S-oxiracetam.
Pharmacokinetics: No interconversion between R- and S-enantiomers has been observed. Oxiracetam is well absorbed orally, crosses the BBB, and has a plasma half-life of ~3-4 h in humans. The R-enantiomer likely has similar physicochemical properties but may differ in clearance due to stereoselective metabolism. In rodents, peak plasma concentrations occur within 1-2 h after oral dosing. Protein binding is low. The compound is excreted largely unchanged in urine. Detailed PK for the isolated R-form is not available. |
| Toxicity/Toxicokinetics |
Multiple animal studies suggest that oxiracetam, including its R-enantiomer, is considered safe even when high doses are consumed over long periods. In in vitro cytotoxicity assessments, (R)-oxiracetam did not exhibit明显的 cytotoxic effects at the tested concentrations. According to clinical study literature, adverse reactions to oxiracetam are rare, with a few patients possibly experiencing psychomotor agitation and sleep abnormalities, and isolated cases reporting nausea and gastric discomfort. It should be noted that (R)-Oxiracetam is currently for research use only and has not been approved by the FDA for any medical use. All experiments involving this compound should be conducted in appropriate biosafety cabinets following standard chemical safety practices.
Toxicity: The racemic mixture has been used clinically for years with a good safety profile; common adverse effects are mild (headache, insomnia, GI upset). No specific toxicity data for the R-enantiomer are published. High-dose animal studies show low toxicity. Since it is a single enantiomer, it may have a different safety profile, but no dedicated toxicological studies are public. It is for research use only. |
| References |
[1]. Arch Int Pharmacodyn Ther.1985 May;275(1):86-92;
[2]. Pharmacol Biochem Behav.1987 Jul;27(3):491-5. |
| Additional Infomation |
Additional Information: (R)-Oxiracetam has CAS 68252-28-8, molecular formula C6H10N2O3, MW 158.16. It is also known as ISF-2522. The pharmacological activity of oxiracetam resides mainly in the S-enantiomer; the R-form is weaker and sometimes considered an inactive isomer. Differences in mechanism may stem from chiral structure-dependent receptor binding. It is not FDA-approved as a single entity. Used in research to compare enantiomer activities. For research only, not for human therapy.
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| Molecular Formula |
C6H10N2O3
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| Molecular Weight |
158.16
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| Exact Mass |
158.069
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| Elemental Analysis |
C, 45.57; H, 6.37; N, 17.71; O, 30.35
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| CAS # |
68252-28-8
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| Related CAS # |
(S)-Oxiracetam;88929-35-5;Oxiracetam;62613-82-5
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| PubChem CID |
3051965
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| Appearance |
Typically exists as solid at room temperature
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| Density |
1.4±0.1 g/cm3
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| Boiling Point |
494.6±40.0 °C at 760 mmHg
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| Flash Point |
252.9±27.3 °C
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| Vapour Pressure |
0.0±2.9 mmHg at 25°C
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| Index of Refraction |
1.570
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| LogP |
-2.48
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| Hydrogen Bond Donor Count |
2
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| Hydrogen Bond Acceptor Count |
3
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| Rotatable Bond Count |
2
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| Heavy Atom Count |
11
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| Complexity |
192
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| Defined Atom Stereocenter Count |
1
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| SMILES |
O=C(N)CN1C(C[C@@H](O)C1)=O
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| InChi Key |
IHLAQQPQKRMGSS-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C6H10N2O3/c7-5(10)3-8-2-4(9)1-6(8)11/h4,9H,1-3H2,(H2,7,10)
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| Chemical Name |
4-Hydroxy-2-oxopyrrolidine-N-acetamide
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| Synonyms |
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
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| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
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| Solubility (In Vivo) |
Solubility in Formulation 1: 100 mg/mL (632.27 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.
(Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 6.3227 mL | 31.6136 mL | 63.2271 mL | |
| 5 mM | 1.2645 mL | 6.3227 mL | 12.6454 mL | |
| 10 mM | 0.6323 mL | 3.1614 mL | 6.3227 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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