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.

Pre-Clinical Pharmacokinetic Characterization, Tissue Distribution, and Excretion Studies of Novel Edaravone Oral Prodrug, TEJ-1704

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a free radical scavenger approved for the treatment of amyotrophic lateral sclerosis, a fatal neuromuscular disease. Edaravone is administered as an intravenous infusion over 60 min for several treatment cycles. To ease the burden of patients and caregivers, the oral formulation of edaravone has been developed. The purpose of this study was to evaluate pharmacokinetics and tissue distribution of TEJ-1704, an edaravone oral prodrug, in male Sprague Dawley rats and beagle dogs. Animal experiments were conducted using Sprague Dawley rats and beagle dogs to evaluate pharmacokinetics, tissue distribution, and excretion of TEJ-1704. Blood, tissues, cerebrospinal fluid, urine, and feces samples were collected at designated sampling time after intravenous (IV) or oral (PO) administration of edaravone or TEJ-1704. A modified bioanalysis method was developed to quantify edaravone in samples including plasma, tissues, cerebrospinal fluid, urine, and feces. The bioanalysis method was validated and successfully applied to pharmacokinetics, tissue distribution, and excretion studies of the novel edaravone prodrug. Although plasma C_max of TEJ-1704 was low, groups administered with TEJ-1704 had high AUC_inf, suggesting continuous metabolism of TEJ-1704 into edaravone. Groups treated with TEJ-1704 also showed lower CSF distribution than the control groups. After the administration of TEJ-1704, the majority of edaravone was distributed to the heart, lung, and kidney. It was excreted equally via urine and feces. The pharmacokinetics, tissue distribution, and excretion of TEJ-1704, a novel edaravone oral prodrug, were successfully characterized. Additional studies are needed to fully understand the difference between TEJ-1704 and edaravone and determine the potency of TEJ-1704.

Predicting the Pharmacokinetic Characteristics of Edaravone Intravenous Injection and Sublingual Tablet Through Modeling and Simulation

PURPOSE

Edaravone is a free-radical scavenger with relatively favorable properties of brain penetration. It has been approved for the indications of acute ischemic stroke and amyotrophic lateral sclerosis (ALS). This study aimed to establish a pharmacokinetic (PK) model to fit the PK profile of edaravone after a single sublingual (SL) dose of a novel edaravone tablet and single IV infusion of injectable edaravone in healthy Chinese volunteers participating in a bioavailability study. The model is expected to be useful for predicting the concentration-time profiles of edaravone following different dosing regimens in a healthy Chinese population. The purposes were to identify an optimal dose and dosing regimen for the new SL formulation and to support future clinical exploration of this tablet product in its approved indications and other therapeutic fields being developed.

METHODS

The PK profiles after a single SL dose or IV infusion of edaravone 30 mg can be well described by a 3-compartment linear disposition model, on which a first-order absorption model with a lag time and a parameter for bioavailability was incorporated to fit the absorption phase of the SL dose. Performance of these PK models was evaluated for goodness of fit, residual trends, visual predictive checks, as well as precision of model predictions against external data. The validated models were employed for simulating the PK profiles of edaravone after a single SL dose of 60 mg and IV infusion of 60 mg for 60 min.

FINDINGS

The resultant estimates support the possibility and feasibility of demonstrating bioequivalence between an SL administration of edaravone 60 mg and the currently approved dosing regimen for ALS (ie, 60 mg IV over 60 min) once per day. The calculation of sample size suggested that the requirement for subject number was acceptable considering the general capacity of a Phase I study center, and so were the procedures defined in the protocol.

IMPLICATION

The models can be further applied to simulate favorable concentration-time profiles in diseases with different underlying courses of oxidative stress, and hence facilitate the optimization of current dosing regimens.

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.