Eluxadoline in the treatment of diarrhea-predominant irritable bowel syndrome

Pharmacokinetic considerations for drugs that treat diarrhea-predominant irritable bowel syndrome: what's new?

INTRODUCTION

Irritable bowel syndrome (IBS), which presents a significant healthcare and socioeconomic burden, is one of the main issues in the field of therapy. Hence, it is imperative to tackle this matter by evaluating the safety and efficacy of the available treatments and determining the ideal approach for each patient.

AREAS COVERED

We reviewed the pharmacokinetics and safety of pharmacologic interventions administered in diarrhea-predominant IBS (IBS-D) patients. PubMed, Google Scholar and the USFDA databases were searched up to November 2023 to include all updated information on eluxadoline, alosetron, and rifaximin.

EXPERT OPINION

The most effective way to treat IBS-D is to focus on managing the most common symptoms. However, healthcare providers face a challenge when it comes to identifying the right treatment for each patient, and the root cause of this is the diversity of IBS-D population. Studies have shown that there are differences in how men and women metabolize drugs, which may lead to gender-specific adverse reactions. Women tend to have higher drug concentrations in their bloodstream and take longer to eliminate them. Therefore, healthcare providers may need to reduce the dosage for female patients. Integrating IBS care into sustainable development efforts can indirectly contribute to achieving SDGs and promote health and well-being for all.

Eluxadoline-Loaded Eudragit Nanoparticles for Irritable Bowel Syndrome with Diarrhea: Formulation, Optimization Using Box-Behnken Design, and Anti-Diarrheal Activity

Eluxadoline (ELD), a recently approved drug, exhibits potential therapeutic effects in the management and treatment of IBS-D. However, its applications have been limited due to poor aqueous solubility, leading to a low dissolution rate and oral bioavailability. The current study's goals are to prepare ELD-loaded eudragit (EG) nanoparticles (ENPs) and to investigate the anti-diarrheal activity on rats. The prepared ELD-loaded EG-NPs (ENP1-ENP14) were optimized with the help of Box-Behnken Design Expert software. The developed formulation (ENP2) was optimized based on the particle size (286 ± 3.67 nm), PDI (0.263 ± 0.01), and zeta potential (31.8 ± 3.18 mV). The optimized formulation (ENP2) exhibited a sustained release behavior with maximum drug release and followed the Higuchi model. The chronic restraint stress (CRS) was successfully used to develop the IBS-D rat model, which led to increased defecation frequency. The in vivo studies revealed a significant reduction in defecation frequency and disease activity index by ENP2 compared with pure ELD. Thus, the results demonstrated that the developed eudragit-based polymeric nanoparticles can act as a potential approach for the effective delivery of eluxadoline through oral administration for irritable bowel syndrome diarrhea treatment.

An Open-Label Study to Evaluate the Effect of Eluxadoline on the Single-Dose Pharmacokinetics of Midazolam in Healthy Participants

Eluxadoline is a mixed μ-opioid, κ-opioid receptor agonist, and δ-opioid receptor antagonist, approved in the United States for adults with diarrhea-predominant irritable bowel syndrome. This phase 1, single-center, open-label, single-sequence study was conducted on 30 healthy participants to establish whether steady-state eluxadoline increases systemic exposure of the cytochrome P450 (CYP) 3A4 substrate midazolam. Participants received oral midazolam 4 mg on day 1 with a 7-day washout period. On days 8-16, oral eluxadoline 100 mg was administered twice daily. On day 15, midazolam 4 mg was coadministered with the eluxadoline 100-mg morning dose. Primary outcome measures were pharmacokinetic parameters of midazolam and 1-hydroxy-midazolam. The midazolam and 1-hydroxy-midazolam geometric mean ratios and 90%CIs for maximum plasma drug concentration were 99.0% (91.6-107.0) and 113.8% (104.9-123.5), respectively, and area under the plasma concentration-time curves were 90.5% (83.9-97.6) and 105.1% (99.8-110.7), respectively, demonstrating the 2 treatments were bioequivalent, and there was no clinically significant drug interaction. All treatment-emergent adverse events were treatment related, mild in intensity, with no serious adverse events. These results suggest that eluxadoline has no clinically significant effect on CYP3A4 activity and is, therefore, unlikely to affect the pharmacokinetics of other CYP3A4 substrates.

Eluxadoline Versus Antispasmodics in the Treatment of Irritable Bowel Syndrome: An Adjusted Indirect Treatment Comparison Meta-analysis

Objective: Eluxadoline is a newly approved drug for irritable bowel syndrome (IBS), but it has rarely been compared with positive controls. We aimed to compare eluxadoline with antispasmodics in the treatment of IBS. Methods: We searched the OVID Medline, Embase, and the Cochrane Central Register of Controlled Trials databases for randomized controlled trials (RCTs) comparing eluxadoline or antispasmodics with placebo. The search was conducted from 1 January 1980, to 1 September 2020, without any language restrictions. The primary efficacy outcome was the relief of abdominal pain, defined by a reduction of pain scores of at least 30% from baseline. The secondary efficacy outcome was the relief of global IBS symptoms, defined by a composite response of a decrease in abdominal pain and improvement in stool consistency on the same day for at least 50% of the days assessed. The data were pooled using a random-effects model. Outcome estimates were pooled by using Risk Ratios (RRs) and P-scores. Results: Forty-two trials with 8,457 participants were included from 45 articles. Compared with placebo, each of drotaverine, pinaverium, alverine combined with simethicone (ACS) and eluxadoline 100 mg was highly effective in the relief of abdominal pain, with drotaverine [RR, 2.71 (95% CI, 1.70 to 4.32), P-score = 0.95] ranking first. Drotaverine, otilonium, cimetropium, pinaverium, and eluxadoline 100 mg had significantly high the relief of global IBS symptomss, for which drotaverine [RR, 2.45 (95% CI, 1.42 to 4.22), P-score = 0.95] was ranked first. No significant difference was found between these interventions. Pinaverium had a significantly higher the relief of global IBS symptoms than eluxadoline [RR, 1.72 (95% CI, 1.33 to 2.21)] on sensitivity analysis. However, no significant difference was found in the number of adverse events between each intervention and the placebo. Conclusion: Our network meta-analysis showed that eluxadoline 100 mg was at least as effective as antispasmodics in relieving abdominal pain in IBS. But eluxadoline had more reported adverse events. Antispasmodics are still the first choice for the treatment of IBS.

Validation of the HPLC–PDA method for detection of eluxadoline and rifaximin in rat plasma and application in a pharmacokinetic study

Background

A precise, simple, accurate, and quick HPLC–PDA method for the determination of eluxadoline and rifaximin in rat plasma was developed and validated in this study. In this method, Loperamide hydrochloride was used as the internal standard and plasma samples were prepared using a liquid–liquid extraction technique for which acetonitrile was a solvent. An Agilent Symmetry C8 column (5 µm, 250 mm × 4.6 mm) at 283 nm and isocratic elution using HPLC grade acetonitrile and 7 mM TEA (pH 2.5) with a ratio of (40: 60 v/v) was used as a mobile phase and the flow rate employed was 1 mL min−1. A satisfactory chromatographic separation was accomplished.

Results

An HPLC–PDA method for the determination of eluxadoline and rifaximin with retention times of 3.06 and 7.82 min, respectively, was developed. The calibration curves appear linear for both eluxadoline and rifaximin in the range of 5–200 ng mL−1 and 10–400 ng mL−1, and the corresponding correlation coefficient values were found to be 0.9999 and 0.9998 respectively. Lower limits of quantification (LLOQ) for eluxadoline and rifaximin were evaluated to be 5.0 ng mL−1 and 10.0 ng mL−1, respectively. The accuracy and precision results in all validation experiments were within the acceptance limits of FDA guidelines.

Conclusion

The developed HPLC–PDA approach was fully validated to meet the USFDA guidelines for bioanalytical method validation in terms of precision, accuracy, and stability. The presented approach could be beneficial for the determination of ELX and RFX in rat plasma, according to validation parameters. This is one of the efficient method to study the pharmacokinetics of ELX and RFX in rats.

Graphical abstract

Importance of Non-pharmacological Approaches for Treating Irritable Bowel Syndrome: Mechanisms and Clinical Relevance

Chronic visceral pain represents a major unmet clinical need with the severity of pain ranging from mild to so severe as to prevent individuals from participating in day-to-day activities and detrimentally affecting their quality of life. Although chronic visceral pain can be multifactorial with many different biological and psychological systems contributing to the onset and severity of symptoms, one of the major triggers for visceral pain is the exposure to emotional and physical stress. Chronic visceral pain that is worsened by stress is a hallmark feature of functional gastrointestinal disorders such as irritable bowel syndrome (IBS). Current pharmacological interventions for patients with chronic visceral pain generally lack efficacy and many are fraught with unwanted side effects. Cognitive behavioral therapy (CBT) has emerged as a psychotherapy that shows efficacy at ameliorating stress-induced chronic visceral pain; however, the molecular mechanisms underlying CBT remain incompletely understood. Preclinical studies in experimental models of stress-induced visceral pain employing environmental enrichment (EE) as an animal model surrogate for CBT are unraveling the mechanism by which environmental signals can lead to long-lasting changes in gene expression and behavior. Evidence suggests that EE signaling interacts with stress and nociceptive signaling. This review will (1) critically evaluate the behavioral and molecular changes that lead to chronic pain in IBS, (2) summarize the pharmacological and non-pharmacological approaches used to treat IBS patients, and (3) provide experimental evidence supporting the potential mechanisms by which CBT ameliorates stress-induced visceral pain.