Riluzole oral suspension in amyotrophic lateral sclerosis: a guide to its use

Controlling the Solubility, Release Rate and Permeation of Riluzole with Cyclodextrins

Riluzole (RLZ), a sodium channel-blocking benzothiazole anticonvulsant BCS class II drug, is very slightly soluble in aqueous medium. To improve aqueous solubility and modulate dissolution rate and membrane permeability, complex formation of RLZ with two cyclodextrin, α-cyclodextrin (α-CD) and sulfobutylether-β-cyclodextrin (SBE-β-CD), was studied. The stability constants demonstrated a greater affinity of SBE-β-CD towards RLZ compared to α-CD. A solubility growth of 1.7-fold and 3.7-fold with α-CD and SBE-β-CD, respectively, was detected in the solutions of 1% cyclodextrins and accompanied by the permeability reduction. For 1% CD solutions, several biopolymers (1% w/v) were tested for the membrane permeability under static conditions. The synergistic positive effect of α-CD and polymer on the solubility accompanied by unchanged permeability was revealed in RLZ/α-CD/PG, RLZ/α-CD/PEG400, and RLZ/α-CD/PEG1000 systems. Solid RLZ/CD complexes were prepared. Dynamic dissolution/permeation experiments for the solid samples disclosed the characteristic features of the release processes and permeation rate through different artificial membranes. The maximal permeation rate was determined across the hydrophilic semi-permeable cellulose membrane followed by the lipophilic PermeaPad barrier (model of intestinal and buccal absorption) and polydimethylsiloxane-polycarbonate membrane (simulating transdermal delivery way). Different mode of the permeation between the membranes was estimated and discussed.

Riluzole Oral Suspension for the Treatment of Amyotrophic Lateral Sclerosis: Texture and Compatibility with Food Thickeners Evaluation

Riluzole 5 mg/mL oral suspension is the only licensed liquid medicine to treat Amyotrophic Lateral Sclerosis (ALS) orally. As more than 80% of ALS patients develop dysphagia, an oral liquid formulation provides an important therapeutic option. The Riluzole 5 mg/mL oral suspension is administered by means of the graduated oral dosing syringe included in the medicine package. Its concentration (5 mg/mL) is consistent with a small and easy to measure volume (10 mL) to deliver the prescribed 50-mg dose twice daily. This work had a dual objective. The first was to evaluate the texture of the Riluzole 5 mg/mL oral suspension according to the International Dysphagia Diet Standardisation Initiative (IDDSI) flow test. Results of this experiment indicated that Riluzole 5 mg/mL oral suspension would basically fall under the “mildly thick” IDDSI descriptors. This is an important feature because thick fluids facilitate a safer swallow in patients with dysphagia. As a second objective, we evaluated for scientific purposes the compatibility of Riluzole 5 mg/mL oral suspension with some of the most common food thickeners available on the market. Intimate mixtures of the Riluzole 5 mg/mL oral suspension with thickeners were evaluated for appearance, pH, Riluzole assay and Riluzole related substances immediately after preparation and after two hours at room temperature. Riluzole 5 mg/mL oral suspension resulted to be compatible with all the marketed thickeners tested.

Ketogenic therapy in neurodegenerative and psychiatric disorders: From mice to men

Ketogenic diet is a low carbohydrate and high fat diet that has been used for over 100 years in the management of childhood refractory epilepsy. More recently, ketogenic diet has been investigated for a number of metabolic, neurodegenerative and neurodevelopmental disorders. In this comprehensive review, we critically examine the potential therapeutic benefits of ketogenic diet and ketogenic agents on neurodegenerative and psychiatric disorders in humans and translationally valid animal models. The preclinical literature provides strong support for the efficacy of ketogenic diet in a variety of diverse animal models of neuropsychiatric disorders. However, the evidence from clinical studies, while encouraging, particularly in Alzheimer's disease, psychotic and autism spectrum disorders, is limited to case studies and small pilot trials. Firm conclusion on the efficacy of ketogenic diet in psychiatric disorders cannot be drawn due to the lack of randomised, controlled clinical trials. The potential mechanisms of action of ketogenic therapy in these disorders with diverse pathophysiology may include energy metabolism, oxidative stress and immune/inflammatory processes. In conclusion, while ketogenic diet and ketogenic substances hold promise pre-clinically in a variety of neurodegenerative and psychiatric disorders, further studies, particularly randomised controlled clinical trials, are warranted to better understand their clinical efficacy and potential side effects.

Dysphagia in Amyotrophic Lateral Sclerosis: Impact on Patient Behavior, Diet Adaptation, and Riluzole Management

This retrospective study aimed to investigate the clinical features associated with deteriorated swallow in amyotrophic lateral sclerosis (ALS) patients with spinal and bulbar onset, describe the modification of diet and liquid intake, and assess the impact of dysphagia on the use of riluzole. One hundred forty-five patients were observed periodically every 3–6 months. They underwent routinely fiberoptic endoscopic evaluation of swallowing (FEES) and spirometry; dysphagia severity was classified according to the Penetration Aspiration Scale and the Pooling score (P-score) integrated with other parameters such as sensation, collaboration, and age (P-SCA score). During a mean follow-up period of about 2 years, the percentage of ALS patients suffering from dysphagia increased to 85 (rising from 35 to 73% in patients with spinal onset and from 95 to 98% in those with bulbar onset). Also, 8% of patients with dysphagia by FEES did not perceive the disorder. The frequency of normal and semi-solid diets decreased over time, while that of pureed diets and percutaneous endoscopic gastrostomy (PEG) prescription increased. Forty-four percent of dysphagic patients refused thickeners or PEG. A significant difference was observed in the mortality rate between patients untreated with riluzole and patients treated with riluzole oral suspension (p < 0.05). Disease duration mainly impacted on the frequency of dysphagia in spinal onset patients, appearing very early in those with bulbar onset. Riluzole oral suspension would allow the safe administration in dysphagic ALS patients to avoid tablet crushing and consequent dispersion in food, common practices that are inconsistent with the safe and effective use of the drug.