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

Effect of food on oral pharmacokinetics of edaravone coamorphous dispersion containing bile salts as coformers - Part II

OBJECTIVES

Edaravone (EDR) is an effective neuroprotective agent in various neurological diseases; however, its use is restricted due to poor oral absorption. Bile salts are known for improving solubility and inhibiting drug crystallization in supersaturated conditions of the gastrointestinal tract (GIT). In our previous work, we prepared coamorphous dispersion (COAM) of EDR with sodium taurocholate (NaTC) using spray drying. The optimized EDR COAM exhibited superior in vitro performance compared to plain EDR. EDR is well absorbed in fasted-over-fed conditions.

METHODS

The present work, we conducted a pharmacokinetic study for EDR and EDR COAM in fasted and fed conditions to check effect of food on its oral absorption. The LC-MS/MS-based method was developed and validated to determine the amount of EDR in plasma.

RESULTS

The results suggested that EDR COAM did not show a significant difference in Cmax (P=0.3544) and AUC (P=0.1696) of fasted and fed states. On the other hand, plain EDR showed 2-fold and 3-fold reduced Cmax (P<0.0001) and AUC (P=0.0094) in the fed condition, respectively. The Cmax and AUC of EDR COAM were improved in fasted (AUC: 2.56-fold) and fed states (AUC: 5.74-fold) than plain EDR, suggesting better oral absorption of COAM than crystalline EDR without having the effect of food.

CONCLUSIONS

The unique structural attributes of NaTC had the potential to inhibit the recrystallization of EDR in GIT, while concurrently reducing the impact of food on the oral absorption of EDR.

Oral edaravone ameliorates behavioral deficits and pathologies in a valproic acid-induced rat model of autism spectrum disorder

Autism spectrum disorder (ASD) is neurodevelopmental disorder with a high incidence rate, characterized by social deficits and repetitive behaviors. There is currently no effective management available to treat the core symptoms of ASD; however, oxidative stress has been implicated in its pathogenesis. Edaravone (EDA), a free-radical scavenger, is used to treat amyotrophic lateral sclerosis (ALS) and acute ischemic stroke (AIS). Here, we hypothesized that an oral formula of EDA may have therapeutic efficacy in the treatment of core ASD symptoms. A rat model of autism was established by prenatal exposure to valproic acid (VPA), and the offsprings were orally treated with EDA at low (3 mg/kg), medium (10 mg/kg), and high (30 mg/kg) doses once daily for 28 days starting from postnatal day 25 (PND25). Oral EDA administration alleviated the core symptoms in VPA rats in a dose-dependent manner, including repetitive stereotypical behaviors and impaired social interaction. Furthermore, oral administration of EDA significantly reduced oxidative stress in a dose-dependent manner, as evidenced by a reduction in oxidative stress markers and an increase in antioxidants in the blood and brain. In addition, oral EDA significantly attenuated downstream pathologies, including synaptic and mitochondrial damage in the brain. Proteomic analysis further revealed that EDA corrected the imbalance in brain oxidative reduction and mitochondrial proteins induced by prenatal VPA administration. Overall, these findings demonstrate that oral EDA has therapeutic potential for ASD by targeting the oxidative stress pathway of disease pathogenesis and paves the way towards clinical studies.

Oral antioxidant edaravone protects against cognitive deficits induced by chronic hypobaric hypoxia at high altitudes

Chronic hypobaric hypoxia at high altitudes can impair cognitive functions, especially causing deficits in learning and memory, which require therapeutic intervention. Here, we showed that mice subjected to hypobaric hypoxia (simulating an altitude of 5000 m) for one month experienced significant cognitive impairment, accompanied by increased biomarker levels of oxidative stress in the brain and blood. Oral administration of a novel formulation of edaravone, a free radical scavenger approved for the treatment of ischaemic stroke and amyotrophic lateral sclerosis, significantly alleviated oxidative stress and cognitive impairments caused by chronic hypobaric hypoxia. Furthermore, oral edaravone treatment also mitigated neuroinflammation and restored hippocampal neural stem cell exhaustion. Additionally, periostin (Postn) is vital in the cognitive deficits caused by chronic hypobaric hypoxia and may be a molecular target of edaravone. In conclusion, our results suggest that oxidative stress plays a crucial role in the cognitive deficits caused by chronic hypobaric hypoxia and that oral edaravone is a potential medicine for protecting against cognitive deficits caused by chronic hypobaric hypoxia in high-altitude areas.

Self-nanomicellizing solid dispersion: A promising platform for oral drug delivery

Amorphous solid dispersion (ASD) has been widely used to enhance the oral bioavailability of water-insoluble drugs for oral delivery because of its advantages of enhancing solubility and dissolution rate. However, the problems related to drug recrystallization after drug dissolution in media or body fluid have constrained its application. Recently, a self-nanomicellizing solid dispersion (SNMSD) has been developed by incorporating self-micellizing polymers as carriers to settle the problems, markedly improving the ability of supersaturation maintenance and enhancing the oral bioavailability of drug. Spontaneous formation and stability of the self-nanomicelle (SNM) have been proved to be the key to supersaturation maintenance of SNMSD system. This offers a novel research direction for maintaining supersaturation and enhancing the bioavailability of ASDs. To delve into the advantages of SNMSDs, we provide a concise review introducing the formation mechanism, characterization methods and stability of SNMs, emphasizing the advantages of SNMSDs for oral drug delivery facilitated by SNM formation, and discussing relevant research prospects.

Edaravone for the Treatment of Motor Neurone Disease: A Critical Review of Approved and Alternative Formulations against a Proposed Quality Target Product Profile

Edaravone is one of two main drugs for treating motor neurone disease (MND). This review proposes a specific quality target product profile (QTPP) for edaravone following an appraisal of the issues accounting for the poor clinical uptake of the approved IV and oral liquid edaravone formulations. This is followed by a review of the alternative oral formulations of edaravone described in the published patent and journal literature against the QTPP. A total of 14 texts published by six research groups on 18 novel oral formulations of edaravone for the treatment of MND have been reviewed. The alternative oral formulations included liquid and solid formulations developed with cyclodextrins, lipids, surfactants, co-surfactants, alkalising agents, tablet excipients, and co-solvents. Most were intended to deliver edaravone for drug absorption in the lower gastrointestinal tract (GIT); however, there were also four formulations targeting the oral mucosal absorption of edaravone to avoid first-pass metabolism. All the novel formulations improved the aqueous solubility, stability, and oral bioavailability (BA) of edaravone compared to an aqueous suspension of edaravone. A common limitation of the published formulations is the lack of MND-patient-centred data. Except for TW001, no other formulations have been trialled in MND patients. To meet the QTPP of an oral edaravone formulation for MND patients, it is recommended that a tablet of appropriate size and with acceptable taste and stability be designed for the effective sublingual or buccal absorption of edaravone. This tablet should be designed with input from the MND community.

Self-micellizing solid dispersion of tacrolimus: Physicochemical and pharmacokinetic characterization

The present study was undertaken to develop a self-micellizing solid dispersion (SMSD) of tacrolimus (TAC) to improve the biopharmaceutical properties of TAC. An SMSD formulation of TAC (SMSD/TAC) and amorphous solid dispersion formulation of TAC (ASD/TAC) were prepared with Soluplus® , an amphiphilic copolymer, and hydroxypropyl cellulose, respectively. Physicochemical properties were characterized in terms of morphology, crystallinity, storage stability, interaction of TAC with Soluplus® , and micelle-forming potency; pharmacokinetic behavior was also evaluated in rats. Tacrolimus in both formulations was in an amorphous state. After storage at 40°C/75% relativity humidity for 4 weeks, there were no significant changes in the crystallinity of TAC between nonaged and aged SMSD/TAC, whereas slight recrystallization was observed in aged ASD/TAC. The results of circular dichroism (CD) and infrared spectroscopic analyses were indicative of the potent drug-polymer interaction in SMSD/TAC, possibly leading to the prevention of recrystallization. Compared with other TAC samples, SMSD/TAC exhibited significant improvement in the dissolution behavior of TAC through the immediate formation of fine micelles. After the oral administration of TAC samples (10 mg TAC/kg) to rats, there was marked enhancement in systemic exposure to TAC with both formulations; in particular, SMSD/TAC achieved an increase in bioavailability ca. 20-fold higher than crystalline TAC. The SMSD approach might provide an effective dosage form for TAC with enhanced physicochemical stability and oral absorption.

Intranasal administration of edaravone nanoparticles improves its stability and brain bioavailability

The clinical application of EDV, a potent antioxidant drug approved for amyotrophic lateral sclerosis (ALS), is limited by its short biological half-life and poor water solubility necessitating hospitalization during intravenous infusion. Nanotechnology-based drug delivery constitutes a powerful tool through inferring drug stability and targeted drug delivery improving drug bioavailability at the diseased site. Nose-to-brain drug delivery offers direct access to the brain bypassing the blood brain barrier and reducing systemic biodistribution. In this study, we designed EDV-loaded poly(lactic-co-glycolic acid) (PLGA)-based polymeric nanoparticles (NP-EDV) for intranasal administration. NPs were formulated by the nanoprecipitation method. Morphology, EDV loading, physicochemical properties, shelf-life stability, in vitro release and pharmacokinetic assessment in mice were conducted. EDV was efficiently loaded into ∼90 nm NPs, stable up to 30 days of storage, at ∼3% drug loading. NP-EDV reduced H2O2-induced oxidative stress toxicity in mouse microglial cell line BV-2. Optical imaging and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) showed that intranasal delivery of NP-EDV offered higher and more sustained brain uptake of EDV compared to intravenous administration. This study is the first of its kind to develop an ALS drug in a nanoparticulate formulation for nose-to-brain delivery raising hope to ALS patients where currently treatment options are limited to two clinically approved drugs only.

In silico and in vitro investigation of bile salts as coformers for edaravone coamorphous dispersion- Part I

In the present study, we aimed to design the spray-dried coamorphous dispersion (COAM) of a neuroprotective agent-edaravone (EDR) with bile salts to improve oral bioavailability. After the initial screening of different bile salts, EDR-sodium taurocholate (NaTC) COAM showed 4-fold solubility than a pure drug in 1-7pH range. In silico studies to select coformer for COAM revealed a narrow energy gap, easy charge transfer and high chemical reactivity between EDR and NaTC. The optimized EDR-NaTC COAM in a 1:1 molar ratio was characterized for solid state characterizations and in vitro release study. Hydrogen bond formation between the pyrazolone ring of EDR and the -OH group of the phenanthrene ring of NaTC was observed in the ATR-FTIR spectra of COAM. The DSC and XRPD data indicated the formation of an amorphous halo, whereas SEM photographs demonstrated porous, spherical particles of COAM. The pH-independent in vitro drug release of COAM was observed in 0.1N HCl, pH 4.5 and 6.8 buffers which was 3-fold higher than EDR. The COAM was stable for 6 months at accelerated condition without showing a change in drug content or devitrification (Initial: 98.002±0.942%; Accelerated condition: 97.016±1.110%). Although coamorphous form and hydrogen bonding between EDR-NaTC dispersion were primarily responsible for improved dissolution, NaTC, an exceptional surfactant, has also contributed to it. Moreover, its exclusive structural characteristics could prevent the recrystallization of the drug in supersaturated conditions of the GIT and also minimize the effect of food on oral absorption of EDR which will be studied in animals in the second part of this work.

Preclinical validation of a novel oral Edaravone formulation for treatment of frontotemporal dementia

Oxidative stress is a key factor in the pathogenesis of several neurodegenerative disorders and is involved in the accumulation of amyloid beta plaques and Tau inclusions. Edaravone (EDR) is a free radical scavenger that is approved for motor neuron disease and acute ischemic stroke. EDR alleviates pathologies and cognitive impairment of AD via targeting multiple key pathways in transgenic mice. Herein, we aimed to study the effect of EDR on Tau pathology in P301L mice; an animal model of frontotemporal dementia (FTD), at two age time points representing the early and late stages of the disease. A novel EDR formulation was utilized in the study and the drug was delivered orally in drinking water for 3 months. Then, behavioral tests were conducted followed by animal sacrifice and brain dissection. Treatment with EDR improved the reference memory and accuracy in the probe trial as evaluated in Morris water maze, as well as novel object recognition and significantly alleviated motor deficits in these mice. EDR also reduced the levels of 4-hydroxy-2-nonenal and 3-nitrotyrosine adducts. In addition, immunohistochemistry showed that EDR reduced tau phosphorylation and neuroinflammation and partially rescued neurons against oxidative neurotoxicity. Moreover, EDR attenuated downstream pathologies involved in Tau hyperphosphorylation. These results suggest that EDR may be a potential therapeutic agent for the treatment of FTD.

Drug Repurposing: Promises of Edaravone Target Drug in Traumatic Brain Injury

Edaravone is a potent free-radical scavenger that has been in the market for more than 30 years. It was originally developed in Japan to treat strokes and has been used there since 2001. Aside from its anti-oxidative effects, edaravone demonstrated beneficial effects on proinflammatory responses, nitric oxide production, and apoptotic cell death. Interestingly, edaravone has shown neuroprotective effects in several animal models of diseases other than stroke. In particular, edaravone administration was found to be effective in halting amyotrophic lateral sclerosis (ALS) progression during the early stages. Accordingly, after its success in Phase III clinical studies, edaravone has been approved by the FDA as a treatment for ALS patients. Considering its promises in neurological disorders and its safety in patients, edaravone is a drug of interest that can be repurposed for traumatic brain injury (TBI) treatment. Drug repurposing is a novel approach in drug development that identifies drugs for purposes other than their original indication. This review presents the biochemical properties of edaravone along with its effects on several neurological disorders in the hope that it can be adopted for treating TBI patients.

Synthesis and radioprotective effects of novel hybrid compounds containing edaravone analogue and 3-n-butylphthalide ring-opening derivatives

As the potential risk of radiation exposure is increasing, radioprotectors studies are gaining importance. In this study, novel hybrid compounds containing edaravone analogue and 3-n-butylphthalide ring-opening derivatives were synthesized, and their radioprotective effects were evaluated. Among these, compound 10a displayed the highest radioprotective activity in IEC-6 and HFL-1 cells. Its oral administration increased the survival rates of irradiated mice and alleviated total body irradiation (TBI)-induced hematopoietic damage by mitigating myelosuppression and improving hematopoietic stem/progenitor cell frequencies. Furthermore, 10a treatment prevented abdominal irradiation (ABI)-induced structural damage to the small intestine. Experiment results demonstrated that 10a increased the number of Lgr5⁺ intestinal stem cells, lysozyme⁺ Paneth cells and Ki67⁺ transient amplifying cells, and reduced apoptosis of the intestinal epithelium cells in irradiated mice. Moreover, in vitro and in vivo studies demonstrated that the radioprotective activity of 10a is associated to the reduction of oxidative stress and the inhibition of DNA damage. Furthermore, compound 10a downregulated the expressions of p53, Bax, caspase-9 and caspase-3, and upregulated the expression of Bcl-2, suggesting that it could prevent irradiation-induced intestinal damage through the p53-dependent apoptotic pathway. Collectively, these findings demonstrate that 10a is beneficial for the prevention of radiation damage and has the potential to be a radioprotector.

Quality-by-Design Approach for the Development of Nano-Sized Tea Tree Oil Formulation-Impregnated Biocompatible Gel with Antimicrobial Properties

Despite the promising properties of tea tree oil (TTO) as potential therapeutics for several superficial skin conditions, certain limitations such as physical instability and skin irritation have restricted its widespread use. This study focuses on developing a rationally designed lipid-based nanoformulation (TTO-LNF) in accordance with the US Food and Drug Administration standard using a well-recognized quality-by-design (QbD) approach. Using a mixture experimental design, TTO-LNF has been optimized with 5% TTO, 10% surfactant, 5% co-surfactant, and 80% water, which showed a 14.4 ± 4.4 nm droplet size and 0.03 ± 0.01 polydispersity index (PDI). To ease the topical administration, the TTO-LNF gel formulation was further developed using xanthan gum to achieve the desired viscosity and form a gel. The in vitro antibacterial tests of TTO-LNF showed promising inhibitory effects toward both Gram-negative and Gram-positive bacteria. In fact, a complete growth inhibition of S. epidermidis was observed when exposed to TTO-LNF and TTO-LNF gel for 24 h, showing better activity than antibiotic kanamycin (25 µg/mL). Additionally, the in vitro release study showed a sustained release profile with a 50% release in 24 h, which could be beneficial to reduce the toxicity and thereby improve the therapeutic efficacy for long-acting applications. Furthermore, the formulations were remarkably stable at 40 °C/75% Relative humidity (RH) for at least 4 weeks. Therefore, this study presents a promising strategy to develop a biocompatible and stable formulation that can be used for the topical treatment of skin infections.

Expression and Cellular Distribution of P-Glycoprotein and Breast Cancer Resistance Protein in Amyotrophic Lateral Sclerosis Patients

For amyotrophic lateral sclerosis (ALS), achieving and maintaining effective drug levels in the brain is challenging due to the activity of ATP-binding cassette (ABC) transporters which efflux drugs that affect drug exposure and response in the brain. We investigated the expression and cellular distribution of the ABC transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) using immunohistochemistry in spinal cord (SC), motor cortex, and cerebellum from a large cohort of genetically well characterized ALS patients (n = 25) and controls (n = 14). The ALS group included 17 sporadic (sALS) and 8 familial (fALS) patients. Strong P-gp expression was observed in endothelial cells in both control and ALS specimens. Immunohistochemical analysis showed higher P-gp expression in reactive astroglial cells in both gray (ventral horn) and white matter of the SC, as well as in the motor cortex of all ALS patients, as compared with controls. BCRP expression was higher in glia in the SC and in blood vessels and glia in the motor cortex of ALS patients, as compared with controls. P-gp and BCRP immunoreactivity did not differ between sALS and fALS cases. The upregulation of both ABC transporters in the brain may explain multidrug resistance in ALS patients and has implications for the use of both approved and experimental therapeutics.

A Review on Solid Dispersion and Carriers Used Therein for Solubility Enhancement of Poorly Water Soluble Drugs

A large number of hydrophilic and hydrophobic carriers in pharmaceutical excipients are available today which are used for formulation of solid dispersions. Depending on nature of carriers the immediate release solid dispersions and/or controlled release solid dispersions can be formulated. Initially crystalline carriers were used which are transformed into amorphous solid dispersions with enhanced properties. The carriers used previously were mostly synthetic one. Recent trend towards the use of natural carriers have replaced the use of synthetic carriers. This review is the overview of various synthetic, natural, semisynthetic, modified natural hydrophilic carriers used for formulation of solid dispersions.

Nanoformulation strategies for improving intestinal permeability of drugs: A more precise look at permeability assessment methods and pharmacokinetic properties changes

The therapeutic efficacy of orally administered drugs is often restricted by their inherent limited oral bioavailability. Low water solubility, limited permeability through the intestinal barrier, instability in harsh environment of the gastrointestinal (GI) tract and being substrate of the efflux pumps and the cytochrome P450 (CYP) can impair oral drug bioavailability resulting in erratic and variable plasma drug profile. As more drugs with low membrane permeability are developed, new interest is growing to enhance their intestinal permeability and bioavailability. A wide variety of nanosystems have been developed to improve drug transport and absorption. Sufficient evidence exists to suggest that nanoparticles are able to increase the transepithelial transport of drug molecules. However, key questions remained unanswered. What types of nanoparticles are more efficient? What are preclinical (or clinical) achievements of each type of nanoformulation in terms of pharmacokinetic (PK) parameters? Addressing this issue in this paper, we have reviewed the current literature regarding permeability enhancement, permeability assessment methods and changes in PK parameters following administration of various nanoformulations. Although permeability enhancement by various nanoformulations holds great promise for oral drug delivery, many challenges still need to be addressed before development of more clinically successful nanoproducts.

Curcumin-loaded self-nanomicellizing solid dispersion system: part I: development, optimization, characterization, and oral bioavailability

Curcumin (CUR) is considered as one of the most bioactive molecules ever discovered from nature due to its proven anti-inflammatory and antioxidant in both preclinical and clinical studies. Despite its proven safety and efficacy, the clinical translation of CUR into a useful therapeutic agent is still limited due to its poor oral bioavailability. To overcome its limitation and enhance oral bioavailability by improving its aqueous solubility, stability, and intestinal permeability, a novel CUR formulation (NCF) was developed using the self-nanomicellizing solid dispersion strategy. From the initial screening of polymers for their potential to improve the solubility and stability, Soluplus (SOL) was selected. The optimized NCF demonstrated over 20,000-fold improvement in aqueous solubility as a result of amorphization, hydrogen bonding interaction, and micellization determined using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance, dynamic light scattering, and transmission electron microscopy. Moreover, the greater stabilizing effect in alkaline pH and light was observed. Furthermore, significant enhancement of dissolution and permeability of CUR across everted sacs of rat small intestine were noticed. Pharmacokinetic studies demonstrated that the oral bioavailability of CUR was increased 117 and 17-fold in case of NCF and physical mixture of CUR and SOL compared to CUR suspension. These results suggest NCF identified as a promising new approach for repositioning of CUR for pharmaceutical application by enhancing the oral bioavailability of CUR. The findings herein stimulate further in vivo evaluations and clinical tests of NCF.

Curcumin-loaded self-nanomicellizing solid dispersion system: part II: in vivo safety and efficacy assessment against behavior deficit in Alzheimer disease

Curcumin (CUR), a natural polyphenolic compound, is considered as one of the most potential candidates against Alzheimer disease (AD) by targeting multiple pathologies such as amyloid-beta, tau phosphorylation, and oxidative stress. Poor physicochemical profile and oral bioavailability (BA) are the major contributors to its failure in clinical trials. Lack of success in numerous drug clinical trials for the treatment of AD urges the need of repositioning of CUR. To overcome its limitation and enhance oral BA, Novel CUR Formulation (NCF) was developed using self-nanomicellizing solid dispersion strategy which displayed 117-fold enhancement in oral BA of CUR. NCF was tested using SH-SY5Y695 APP human neuroblastoma cell line against the cytotoxicity induced by copper metal ion, H₂O₂, and Aβ42 oligomer and compared with CUR control. The safety and efficacy of NCF on mice AD-like behavioral deficits (open field, novel objective recognition, Y-maze, and Morris water maze tests) were assessed in transgenic AD (APPSwe/PS1deE9) mice model. In SH-SY5Y695 APP human neuroblastoma cell line, NCF showed better safety and efficacy against the cytotoxicity due to the significantly enhancement of cellular uptake. It not only prevents the deterioration of cognitive functions of the aged APPSwe/PS1deE9 mice during aging but also reverses the cognitive functions to their much younger age which is also better than the currently available approved options. Moreover, NCF was proved as well tolerated with no appearance of any significant toxicity via oral administration. The results of the study demonstrated the potential of NCF to improve the efficacy of CUR without compromising its safety profile, and pave the way for clinical development for AD.