Edaravone attenuates intracerebroventricular streptozotocin-induced cognitive impairment in rats

AMPA receptor modulation through sequential treatment with perampanel and aniracetam mitigates post-stroke damage in experimental model of ischemic stroke

The present study evaluates the effect of modulating α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) by inhibiting them in the acute phase and activating them in the sub-acute phase on post-stroke recovery in middle cerebral artery occlusion (MCAo) model of stroke in rats. After 90 min of MCAo, perampanel (an AMPAR antagonist, 1.5 mg/kg i.p) and aniracetam (an AMPA agonist, 50 mg/kg i.p.) were administered for different durations after MCAo. Later, after obtaining the best time point for the antagonist and the agonist treatment protocols, sequential treatment with perampanel and aniracetam were given, and the effect on neurological damage and post stroke recovery were assessed. Perampanel and aniracetam significantly protected MCAo-induced neurological damage and diminished the infarct percentage. Furthermore, treatment with these study drugs improved the motor coordination and grip strength. Sequential treatment with perampanel and aniracetam reduced the infarct percentage as assessed by MRI. Moreover, these compounds diminished the inflammation via reducing the levels of pro-inflammatory cytokines (TNF-α, IL-1β) and increasing the levels of anti-inflammatory cytokine (IL-10) along with reductions in GFAP expression. Moreover, the neuroprotective markers (BDNF and TrkB) were found to be significantly increased. Levels of apoptotic markers (Bax, cleaved-caspase-3; Bcl2 and TUNEL positive cells) and neuronal damage (MAP-2) were normalized with the AMPA antagonist and agonist treatment. Expressions of GluR1 and GluR2 subunits of AMPAR were significantly enhanced with sequential treatment. The present study thus showed that modulation of AMPAR improves neurobehavioral deficits and reduces the infarct percentage through anti-inflammatory, neuroprotective and anti-apoptotic effects.

Chronic Kidney Disease Induces Cognitive Impairment in the Early Stage

OBJECTIVE

Previous research indicates a link between cognitive impairment and chronic kidney disease (CKD), but the underlying factors are not fully understood. This study aimed to investigate the progression of CKD-induced cognitive impairment and the involvement of cognition-related proteins by developing early- and late-stage CKD models in Sprague-Dawley rats.

METHODS

The Morris water maze test and the step-down passive avoidance task were performed to evaluate the cognitive abilities of the rats at 24 weeks after surgery. Histopathologic examinations were conducted to examine renal and hippocampal damage. Real-time PCR, Western blotting analysis, and immunohistochemical staining were carried out to determine the hippocampal expression of brain-derived neurotrophic factor (BDNF), choline acetyltransferase (ChAT), and synaptophysin (SYP).

RESULTS

Compared with the control rats, the rats with early-stage CKD exhibited mild renal damage, while those with late-stage CKD showed significantly increased serum creatinine levels as well as apparent renal and brain damage. The rats with early-stage CKD also demonstrated significantly impaired learning abilities and memory compared with the control rats, with further deterioration observed in the rats with late-stage CKD. Additionally, we observed a significant downregulation of cognition-related proteins in the hippocampus of rats with early-stage CKD, which was further exacerbated with declining renal function as well as worsening brain and renal damage in rats with late-stage CKD.

CONCLUSION

These results suggest the importance of early screening to identify CKD-induced cognitive dysfunction promptly. In addition, the downregulation of cognition-related proteins may play a role in the progression of cognitive dysfunction.

Edaravone Improves Streptozotocin-Induced Memory Impairment via Alleviation of Behavioral Dysfunction, Oxidative Stress, Inflammation, and Histopathological Parameters

Alzheimer's disease (AD), as the main cause of dementia, has a progressive and neurodegenerative pattern with number of cases increasing over the next decades. Therefore, discovering an effective treatment with the ability to invert memory impairment and pathophysiological events of AD seems to be required. The present study performed to investigate the probable effects of Edaravone (EDV) in AD-like disorder induced by intracerebroventricular streptozotocin (ICV-STZ) administration in mice. This study also compares the two different methods of ICV-STZ in the memory impairment induction. NMRI male mice were administrated with 3 mg/kg of STZ for two times during 48 hours span, and after 24 hours, animals were treated with EDV (5 and 10 mg/kg), Donepezil, and Memantine for 14 days. After behavioral tests regarding memory and cognitive function, animals were sacrificed, and the hippocampi were utilized for further analyses. Our results demonstrated that administration of STZ induced memory impairment in the Morris water maze (MWM) test and decreased the discriminative factor in novel object recognition (NOR). The biochemical output shows a significant decrease in ferric reducing antioxidant power (FRAP) and glutathione (GSH) levels followed by increase in malondialdehyde (MDA) and protein carbonylation (PCO) levels. The output showed no difference between the patterns of AD-like disorder induction. Following our treatment groups, administration of EDV (5 and 10 mg/kg), Donepezil, and Memantine significantly improved memory performance and discriminatory behavior. Aforementioned treatments managed to improve FRAP and GSH content of hippocampus, while significantly attenuating MDA, PCO, and nitric oxide overproduction. In addition, no significant difference has been observed between the effect of 5 and 10 mg/kg EDV application. It was supposed that EDV managed to ameliorate memory dysfunction, discriminatory behavior, oxidative stress, and cellular antioxidant power in a dose-independent pattern in mice.

Melatonin reduces β-amyloid accumulation and improves short-term memory in streptozotocin-induced sporadic Alzheimer's disease model

Melatonin is a hormone secreted by the pineal gland, it can be associated with circadian rhythms, aging and neuroprotection. Melatonin levels are decreased in sporadic Alzheimer's disease (sAD) patients, which suggests a relationship between the melatonergic system and sAD. Melatonin may reduce inflammation, oxidative stress, TAU protein hyperphosphorylation, and the formation of β-amyloid (Aβ) aggregates. Therefore, the objective of this work was to investigate the impact of treatment with 10 mg/kg of melatonin (i.p) in the animal model of sAD induced by the intracerebroventricular (ICV) infusion of 3 mg/kg of streptozotocin (STZ). ICV-STZ causes changes in the brain of rats similar to those found in patients with sAD. These changes include; progressive memory decline, the formation of neurofibrillary tangles, senile plaques, disturbances in glucose metabolism, insulin resistance and even reactive astrogliosis characterized by the upregulation of glucose levels and glial fibrillary acidic protein (GFAP). The results show that ICV-STZ caused short-term spatial memory impairment in rats after 30 days of STZ infusion without locomotor impairment which was evaluated on day 27 post-injury. Furthermore, we observed that a prolonged 30-day treatment with melatonin can improve the cognitive impairment of animals in the Y-maze test, but not in the object location test. Finally, we demonstrated that animals receiving ICV-STZ have high levels of Aβ and GFAP in the hippocampus and that treatment with melatonin reduces Aβ levels but does not reduce GFAP levels, concluding that melatonin may be useful to control the progression of amyloid pathology in the brain.

ROCK and PDE-5 Inhibitors for the Treatment of Dementia: Literature Review and Meta-Analysis

Dementia is a disease in which memory, thought, and behavior-related disorders progress gradually due to brain damage caused by injury or disease. It is mainly caused by Alzheimer’s disease or vascular dementia and several other risk factors, including genetic factors. It is difficult to treat as its incidence continues to increase worldwide. Many studies have been performed concerning the treatment of this condition. Rho-associated kinase (ROCK) and phosphodiesterase-5 (PDE-5) are attracting attention as pharmacological treatments to improve the symptoms. This review discusses how ROCK and PDE-5 affect Alzheimer’s disease, vascular restructuring, and exacerbation of neuroinflammation, and how their inhibition helps improve cognitive function. In addition, the results of the animal behavior analysis experiments utilizing the Morris water maze were compared through meta-analysis to analyze the effects of ROCK inhibitors and PDE-5 inhibitors on cognitive function. According to the selection criteria, 997 publications on ROCK and 1772 publications on PDE-5 were screened, and conclusions were drawn through meta-analysis. Both inhibitors showed good improvement in cognitive function tests, and what is expected of the synergy effect of the two drugs was confirmed in this review.

Roflumilast Reduces Pathological Symptoms of Sporadic Alzheimer's Disease in Rats Produced by Intracerebroventricular Streptozotocin by Inhibiting NF-κB/BACE-1 Mediated Aβ Production in the Hippocampus and Activating the cAMP/BDNF Signalling Pathway

Alzheimer's disease (AD) is a neurological disease that gradually causes memory loss and cognitive impairment. The intracellular secondary messenger cyclic nucleotide cAMP helps in memory acquisition and consolidation. In several models of AD, increasing their levels using phosphodiesterase (PDE) inhibitors improved cognitive performance and prevent memory loss. Thus, the current investigation was undertaken to investigate the therapeutic potential of the PDE-4 inhibitor roflumilast (RFM) against intracerebroventricular (ICV) streptozotocin (STZ)-induced sporadic AD in rats. STZ (3 mg/kg) was given to rats via the ICV route on the stereotaxic apparatus, followed by RFM (0.51 mg/kg/oral) treatment for 15 days, and donepezil (5 mg/kg/oral) was employed as a reference standard drug. Subsequently, we observed that RFM dramatically increased rats learning and memory capacities as measured by the Morris water maze and a novel object recognition task. RFM enhanced the levels of cAMP and brain-derived neurotrophic factors (BDNFs) while decreasing the expression of nuclear factor kappa B (NF-κB) and glial fibrillary acidic protein (GFAP) in the hippocampus of ICV-STZ-infused rats. RFM was found to significantly reduce ICV-STZ-induced neuroinflammation, amyloidogenesis, oxidative stress cholinergic impairments, GSK-3β, and phosphorylated tau levels in the rat hippocampus. Supporting these, histopathological study using Cresyl violet and Congo red demonstrated that RFM reduced neuronal alterations and Aβ deposition in the hippocampus of AD rats. These findings suggest that RFM could be a promising candidate for the management of AD by inhibiting NF-κB/BACE-1 mediated Aβ production in the hippocampus and activating the cAMP/BDNF signalling pathway.

Tau Cleavage Contributes to Cognitive Dysfunction in Strepto-Zotocin-Induced Sporadic Alzheimer's Disease (sAD) Mouse Model

Tau cleavage plays a crucial role in the onset and progression of Alzheimer’s Disease (AD), a widespread neurodegenerative disease whose incidence is expected to increase in the next years. While genetic and familial forms of AD (fAD) occurring early in life represent less than 1%, the sporadic and late-onset ones (sAD) are the most common, with ageing being an important risk factor. Intracerebroventricular (ICV) infusion of streptozotocin (STZ)—a compound used in the systemic induction of diabetes due to its ability to damage the pancreatic β cells and to induce insulin resistance—mimics in rodents several behavioral, molecular and histopathological hallmarks of sAD, including memory/learning disturbance, amyloid-β (Aβ) accumulation, tau hyperphosphorylation, oxidative stress and brain glucose hypometabolism. We have demonstrated that pathological truncation of tau at its N-terminal domain occurs into hippocampi from two well-established transgenic lines of fAD animal models, such as Tg2576 and 3xTg mice, and that it’s in vivo neutralization via intravenous (i.v.) administration of the cleavage-specific anti-tau 12A12 monoclonal antibody (mAb) is strongly neuroprotective. Here, we report the therapeutic efficacy of 12A12mAb in STZ-infused mice after 14 days (short-term immunization, STIR) and 21 days (long-term immunization regimen, LTIR) of i.v. delivery. A virtually complete recovery was detected after three weeks of 12A12mAb immunization in both novel object recognition test (NORT) and object place recognition task (OPRT). Consistently, three weeks of this immunization regimen relieved in hippocampi from ICV-STZ mice the AD-like up-regulation of amyloid precursor protein (APP), the tau hyperphosphorylation and neuroinflammation, likely due to modulation of the PI3K/AKT/GSK3-β axis and the AMP-activated protein kinase (AMPK) activities. Cerebral oxidative stress, mitochondrial impairment, synaptic and histological alterations occurring in STZ-infused mice were also strongly attenuated by 12A12mAb delivery. These results further strengthen the causal role of N-terminal tau cleavage in AD pathogenesis and indicate that its specific neutralization by non-invasive administration of 12A12mAb can be a therapeutic option for both fAD and sAD patients, as well as for those showing type 2 diabetes as a comorbidity.

Sinapic Acid Alleviates Oxidative Stress and Neuro-Inflammatory Changes in Sporadic Model of Alzheimer's Disease in Rats

The role of oxidative stress, neuro-inflammation and cholinergic dysfunction is already established in the development of Alzheimer's disease (AD). Sinapic acid (SA), a hydroxylcinnamic acid derivative, has shown neuro-protective effects. The current study evaluates the neuro-protective potential of SA in intracerebroventricular streptozotocin (ICV-STZ) induced cognitive impairment in rats. Male Wistar rats were bilaterally injected with ICV-STZ. SA was administered intragastrically once daily for three weeks. Rats were divided into sham, ICV-STZ, STZ + SA (10 mg/kg), STZ + SA (20 mg/kg) and SA per se (20 mg/kg). Behavioral tests were assessed on day 0 and 21 days after STZ. Later, rats were sacrificed for biochemical parameters, pro-inflammatory cytokines, choline acetyltransferase (ChAT) expression and neuronal loss in the CA1 region of the hippocampus. The results showed that SA 20 mg/kg significantly (p < 0.05) improved cognitive impairment as assessed by Morris water maze and passive avoidance tests. SA 20 mg/kg reinstated the altered levels of GSH, MDA, TNF-α and IL-1β in the cortex and hippocampus. STZ-induced decreased expression of ChAT and neuronal loss were also significantly (p < 0.05) improved with SA. Our results showed that SA exhibits neuro-protection against ICV-STZ induced oxidative stress, neuro-inflammation, cholinergic dysfunction and neuronal loss, suggesting its potential in improving learning and memory in patients of AD.

Development, optimisation and evaluation of chitosan nanoparticles of alendronate against Alzheimer's disease in intracerebroventricular streptozotocin model for brain delivery

The current study aimed to develop alendronate (ALN)-loaded chitosan nanoparticles (CS-ALN-NPs) for brain delivery via intranasal route. These CS-ALN-NPs reduced the peripheral side effects and released ALN directly to brain. These NPs were formulated through ionic gelation technique by mixing sodium tripolyphosphate (1.5 mg/ml) in ALN-CS (1.75 mg/ml) solution. CS-ALN-NPs attained 135.75 ± 5.80 nm, 0.21 ± 0.013, 23.8 ± 3.69 mV, 72.46 ± 0.879% and 30.92 ± 0.375% mean particle size, PDI, zeta potential, entrapment efficiency and loading capacity, respectively. Furthermore, the TEM and SEM analysis of CS-ALN-NPs, respectively, revealed the particle size in 200 nm range and spherical shape. The in vitro and ex vivo release profile revealed a sustained drug release through CS-ALN-NPs as compared to pure drug solution. Also these NPs acquired a high concentration in mice brain and better pharmacokinetic profile than ALN solution (intranasal) CS-ALN-NPs were then evaluated against intracerebroventricular-streptozotocin (ICV-STZ) induced Alzheimer's disease (AD)-like pathologies in mice. The intranasal CS-ALN-NP altered the ICV-STZ induced neurobehavioral, neurochemical and histopathological changes in mice. These effects were significant to those of ALN solution (intranasal). The neuroprotective potential of CS-ALN-NPs observed in ICV-STZ mice model of AD may be a promising brain-targeted delivery system for AD treatment along with further extensive exploration at both pre-clinical and clinical edge. HIGHLIGHTS CS-ALN-NPs were developed and optimised to overcome the poor pharmacokinetic profile and associated side effects of ALN CS-ALN-NPs showed particle size within 200 nm range as well as controlled and sustained release in in vitro release study These optimised NPs of ALN attained higher brain:blood ratio and better pharmacokinetic profile (Cmax, tmax, AUC) CS-ALN-NPs markedly altered ICV STZ induced impairment in cognitive functions of mice and changes in APP processing, neuroinflammatory cytokines and other biochemical parameters in mice hippocampus.

Hesperetin nanoparticles attenuate anxiogenic-like behavior and cerebral oxidative stress through the upregulation of antioxidant enzyme expression in experimental dementia of Alzheimer's type

Background: In this study, we investigate the neuroprotective effects of Hesperetin (Hst) and Nano-Hst on anxiogenic-like behavior and cerebral antioxidant defenses at transcriptional and enzymatic levels in a streptozotocin (STZ)-induced Alzheimer rat model.Methods: Wistar rats were administrated with Hst and Nano-Hst (10 and 20 mg/kg/d) for three weeks. The elevated plus-maze test assessed anxiogenic-like behavior. After behavioral test, activity and gene expression of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GRx) enzymes, as well as malondialdehyde (MDA) and glutathione (GSH) levels, were measured in the cerebral cortex.Results: Based on our results, a rat model of Alzheimer's disease (AD) exhibited anxiogenic-like behavior, activity and gene expression of cerebral antioxidant enzymes and GSH level was decreased while the MDA level was increased. Hst and Nano-Hst treatment reversed anxiogenic-like behavior, and the activities of antioxidant enzymes were elevated. Hst and Nano-Hst effects on the gene expression of CAT, SOD and GRx were confirmed by quantitative real-time PCR (qRT-PCR) in which the expression levels of these genes in the cerebral brain were significantly increased compared to STZ group.Conclusions: These findings indicated that the administration of Hst and Nano-Hst may be used to treat anxiety -related to AD via an up-regulation of cerebral antioxidant enzyme gene.

Protective Effect of Edaravone on Cyclophosphamide Induced Oxidative Stress and Neurotoxicity in Rats

BACKGROUND

Cyclophosphamide (CPA) is the most widely prescribed cancer chemotherapeutic agent which shows serious neurotoxic side effect. Generation of reactive oxygen species at the cellular level is the basic mechanism of cyclophosphamide induced neurotoxicity. Edaravone is the synthetic drug used for brain stroke and has potent antioxidant property.

OBJECTIVE

This study aimed to investigate the effect of edaravone on neurobehavioral and neuropathological alteration induced by cyclophosphamide in male rats.

METHODS

Twenty eight Sprague-Dawley rats were equally divided into four groups of seven rats in each. The control group received saline, and other groups were given CPA intraperitoneally (100 mg/kg), CPA (100 mg/kg) intraperitoneally + Edaravone (10 mg/kg) orally, or Edaravone (10 mg/kg) orally for one month.

RESULTS

Our data showed that CPA significantly elevated brain AChE activity in the hippocampal region. A decrease in the total antioxidant capacity and a reduction in the CAT, SOD, and GPX activity occurred in the brains of the rats exposed to CPA. CPA-treated rats showed a significant impairment in long-termmemory and motor coordination. These results were supported by histopathological observations of the brain. Results revealed that administration of edaravone reversed AChE activity alternation and ameliorated behavioral and histopathological changes induced by CPA.

CONCLUSION

This study suggests that co-administration of edaravone with cyclophosphamide may be a useful intriguing therapeutic approach to overcome cyclophosphamide induced neurotoxicity.

Exendin-4 attenuates pain-induced cognitive impairment by alleviating hippocampal neuroinflammation in a rat model of spinal nerve ligation

Glucagon-like peptide-1 receptor has anti-apoptotic, anti-inflammatory, and neuroprotective effects. It is now recognized that the occurrence and development of chronic pain are strongly associated with anti-inflammatory responses; however, it is not clear whether glucagon-like peptide-1 receptor regulates chronic pain via anti-inflammatory mechanisms. We explored the effects of glucagon-like peptide-1 receptor on nociception, cognition, and neuroinflammation in chronic pain. A rat model of chronic pain was established using left L5 spinal nerve ligation. The glucagon-like peptide-1 receptor agonist exendin-4 was intrathecally injected into rats from 10 to 21 days after spinal nerve ligation. Electrophysiological examinations showed that, after treatment with exendin-4, paw withdrawal frequency of the left limb was significantly reduced, and pain was relieved. In addition, in the Morris water maze test, escape latency increased and the time to reach the platform decreased following exendin-4 treatment. Immunohistochemical staining and western blot assays revealed an increase in the numbers of activated microglia and astrocytes in the dentate gyrus of rat hippocampus, as well as an increase in the expression of tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6. All of these effects could be reversed by exendin-4 treatment. These findings suggest that exendin-4 can alleviate pain-induced neuroinflammatory responses and promote the recovery of cognitive function via the glucagon-like peptide-1 receptor pathway. All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Renmin Hospital of Wuhan University of China (approval No. WDRM 20171214) on September 22, 2017.

Docosahexaenoic Acid Increases the Potency of Soluble Epoxide Hydrolase Inhibitor in Alleviating Streptozotocin-Induced Alzheimer's Disease-Like Complications of Diabetes

Diabetes is a risk factor for Alzheimer's disease and it is associated with significant memory loss. In the present study, we hypothesized that the soluble epoxide hydrolase (sEH) inhibitor N-[1-(1-oxopropyl)-4-piperidinyl]-N'-[4-(trifluoromethoxy)phenyl)-urea (also known as TPPU) could alleviate diabetes-aggravated Alzheimer's disease-like symptoms by improving memory and cognition, and reducing the oxidative stress and inflammation associated with this condition. Also, we evaluated the effect of edaravone, an antioxidant on diabetes-induced Alzheimer's-like complications and the additive effect of docosahexaenoic acid (DHA) on the efficacy of TPPU. Diabetes was induced in male Sprague-Dawley rats by intraperitoneally administering streptozotocin (STZ). Six weeks after induction of diabetes, animals were either treated with vehicle, edaravone (3 or 10 mg/kg), TPPU (1 mg/kg) or TPPU (1 mg/kg) + DHA (100 mg/kg) for 2 weeks. The results demonstrate that the treatments increased the memory response of diabetic rats, in comparison to untreated diabetic rats. Indeed, DHA + TPPU were more effective than TPPU alone in reducing the symptoms monitored. All drug treatments reduced oxidative stress and minimized inflammation in the brain of diabetic rats. Expression of the amyloid precursor protein (APP) was increased in the brain of diabetic rats. Treatment with edaravone (10 mg/kg), TPPU or TPPU + DHA minimized the level of APP. The activity of acetylcholinesterase (AChE) which metabolizes acetylcholine was increased in the brain of diabetic rats. All the treatments except edaravone (3 mg/kg) were effective in decreasing the activity of AChE and TPPU + DHA was more efficacious than TPPU alone. Intriguingly, the histological changes in hippocampus after treatment with TPPU + DHA showed significant protection of neurons against STZ-induced neuronal damage. Overall, we found that DHA improved the efficacy of TPPU in increasing neuronal survival and memory, decreasing oxidative stress and inflammation possibly by stabilizing anti-inflammatory and neuroprotective epoxides of DHA. In the future, further evaluating the detailed mechanisms of action of sEH inhibitor and DHA could help to develop a strategy for the management of Alzheimer's-like complications in diabetes.

Ameliorative effect of alendronate against intracerebroventricular streptozotocin induced alteration in neurobehavioral, neuroinflammation and biochemical parameters with emphasis on Aβ and BACE-1

Alzheimer's disease (AD) is the most prevalent age related neurodegenerative disorder manifested by progressive cognitive decline and neuronal loss in the brain, yet precise etiopathology of majority of sporadic or late-onset AD cases is unknown. AD is associated with various pathological events such as Aβ deposition due to BACE-1 induced cleavage of APP, neuroinflammation, increased cholesterol synthesis, cholinergic deficit and oxidative stress. It was found that bone drug, alendronate (ALN) that cross blood brain barrier inhibits brain cholesterol synthesis and AChE enzyme activity. As cholesterol modifying agents have been supposed to alter AD like pathologies, the current study was designed to investigate the possible neuroprotective and therapeutic potential of ALN against ICV STZ induced experimental sporadic AD (SAD) in mice in a non-cholesterol dependent manner, using donepezil (5 mg/kg) as a reference standard. The preliminary study was done by molecular modelling to identify the binding affinity of ALN with BACE-1 in silico. The prevention of cognitive impairment in mice induced by ICV STZ (3 mg/kg) infused on first and third day, by ALN (1.76 mg/kg p.o.) administered for 15 consecutive days was assessed through Spontaneous Alternation Behavior (SAB) and Morris water maze (MWM) test. Additionally, the protective effect of ALN was also observed by the reversal of altered levels of Aβ_1-42, BACE-,1 neuroinflammatory cytokines, AChE activity and oxidative stress markers (except TBARS) in ICV-STZ infused mice. However, the findings of the present study imply the therapeutic potential of ALN against SAD-like complications.

Self-nanomicellizing solid dispersion of edaravone: part I - oral bioavailability improvement

Background

Edaravone (EDR) is known for its free radical scavenging, antiapoptotic, antinecrotic, and anticytokine effects in neurological and non-neurological diseases. It is currently available clinically as Radicava^® and Radicut^®, intravenous medications, recently approved for the treatment of amyotrophic lateral sclerosis and cerebral infarction. However, the oral use of EDR is still restricted by its poor oral bioavailability (BA) due to poor aqueous solubility, stability, rapid metabolism, and low permeability. The present study reports the development of novel EDR formulation (NEF) using self-nanomicellizing solid dispersion (SNMSD) strategy with the aim to enable its oral use.

Materials and methods

The selection of a suitable carrier for the development of NEF was performed based on the miscibility study. The optimization of EDR-to-carrier ratio was conducted via kinetic solubility study after preparing SNMSDs using solvent evaporation technique. The drug–polymer carrier interaction and self-nanomicellizing properties of NEF were investigated with advanced characterization studies. In vitro permeation, metabolism, and dissolution study was carried out to examine the effect of the presence of a carrier on physico-chemical properties of EDR. Additionally, the dose-dependent pharmacokinetic study of NEF was conducted and compared with the EDR suspension.

Results

Soluplus^® (SOL) as a carrier was selected based on the potential for improving aqueous solubility. The NEF containing EDR and SOL (1:5) resulted in the highest enhancement in aqueous solubility (17.53-fold) due to amorphization, hydrogen bonding interaction, and micellization. Moreover, the NEF demonstrated significant improvement in metabolism, permeability, and dissolution profile of EDR. Furthermore, the oral BA of NEF showed 10.2-, 16.1-, and 14.8-fold enhancement compared to EDR suspension at 46, 138, and 414 µmol/kg doses.

Conclusion

The results demonstrated that SNMSD strategy could serve as a promising way to enhance EDR oral BA and NEF could be a potential candidate for the treatment of diseases in which oxidative stress plays a key role in their pathogenesis.