μ/κ-opioid receptor

Eluxadoline (ELD) is local-acting and exhibits diverse pharmacological effects, including m-OR and kappa opioid receptor agonists and delta opioid receptor antagonists. It exerts negligible oral bioavailability yet is officially approved by the United States Food and Drug Administration for IBS-D treatment. Due to its collective pharmacological properties, ELD significantly decreases the gut motility and reduces the probabilities of drug-induced constipation issues [1].

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 [1].

A Box–Behnken response surface approach experimental design (Design-Expert® Software Version 13) was used to optimize the eluxadoline-loaded eudragit nanoparticles (ENPs) (3 factors, 3 levels). The independent variables selected were: the weight of the eudragit polymer (X1), %w/v, PVA (X2), and sonication time (X3), with their high, medium, and low levels for the preparation of 14 formulations, as shown in Table 1. Particle size (Y1), polydispersity index (Y2), and zeta potential (Y3) were the responses that were examined. Additionally, 3D response surface graphs were plotted to show how the specified factors affected the responses that were measured [1].

In Vitro Drug Release Studies [1]
In vitro drug release studies were performed to analyze the drug release behavior and the release mechanism of the optimized formulation. The analysis of pure ELD and the optimized formulation (ENP2) were determined using the dialysis membrane method. The pure ELD and ENP2 (5 mL) were loaded into the dialysis bag (Spectra/Por® Standard RC Tubing, MWCO 12 KDa) and tied at both ends. Then, the bags were dipped into a beaker containing a dissolution medium of pH 1.2 and pH 6.8 (200 mL), maintained at a temperature of 37 ± 2 °C, and kept under stirring at 100 rpm. At pre-estimated time intervals, 0.5 mL aliquots were withdrawn from each beaker and the sink condition was maintained by adding fresh media [31]. Furthermore, the aliquots were analyzed for drug content by the HPLC method and the percent drug release was calculated and plotted against the time. [30]. All the studies were performed in triplicate (n = 3). Additionally, the drug release mechanism of ELD from the optimized formulation at pH (1.2 and 6.8) was estimated by fitting the drug release results into different mathematical modeling, including zero order, first order, Higuchi, and Korsmeyer–Peppas kinetics models

In this study, the IBS rat model was induced by chronic restraint stress (CRS) as described by Lu et al. All rats were randomly divided into two groups (24 rats in the model group and 6 rats in the control group) after 7 days of adaptation. The rats in the model group were subjected to CRS using an elastic bandage to restrict the movement of the upper body and forelimbs and then anesthetized with ether. Their fore shoulders, upper forelimbs, and thoracic trunk were wrapped in elastic bandage for 2 h each day for 14 days to produce a steady and consistent amount of stimulation to restrict but not prevent movement. The control animals were anesthetized with ether but not restrained. [1]
Grouping and Administration
The rats were divided into five groups (n = 6) as follows:
Normal control group (NC): normal rats received saline (1 mL/kg).
IBS control group (IBS-C): CRS rats received saline (1 mL/kg).
Reference group (REF): CRS rats received loperamide (LRD) at 10 mg/kg.
Pure drug group (ELD-std): CRS rats received (20 mg/kg).
Formulation group (ENP2): CRS rats received (20 mg/kg).
Treatments were administered orally, started 6 h after IBS induction, and continued for 14 consecutive days. Body weights were recorded daily.

Absorption, Distribution and Excretion
Iruzadolin has a low oral absorption rate, estimated at 1.02%, which may be attributed to its poor in vitro gastrointestinal permeability and its zwitterionic nature, resulting in a negative charge across the entire gastrointestinal pH range. 82% is excreted in feces, and <1% in urine. Metabolism/Metabolites The metabolism of iruzadolin is currently unclear, but there is evidence that its limited glucuronidation forms acyl glucuronide metabolites, which are then excreted in urine. Biological Half-Life The mean plasma elimination half-life is 3.7 to 6 hours.

Hepatotoxicity
Elevated serum transaminase levels were uncommon during elushadolin treatment in pre-registration clinical trials. A pooled analysis showed that 2% to 3% of patients in the elushadolin treatment group had ALT levels exceeding three times the upper limit of normal, compared to 1% in the placebo group. More detailed analysis revealed rare cases of significantly elevated ALT and AST levels in the elushadolin treatment group, which were not observed in the placebo group. These more significant elevations were sometimes accompanied by signs of abdominal pain and sphincter of Oddi spasm (as can occur with opioid therapy) or pancreatitis. These abnormalities also primarily occurred in patients without a gallbladder or with a history of pancreatitis or hepatobiliary disease. Following the approval and widespread use of elushadolin, the U.S. Food and Drug Administration (FDA) received over one hundred reports of pancreatitis (including two deaths), leading the FDA to add a "black box warning" to elushadolin, indicating that it is not suitable for patients without a gallbladder. The clinical characteristics of these adverse reactions are not fully described, but they usually occur within the first few weeks of treatment, manifesting as severe abdominal pain and vomiting, sometimes accompanied by significant elevations in ALT and AST, and possibly elevated amylase and lipase. Jaundice is rare, and abnormal liver function is likely due to partial bile duct obstruction. There are currently no reports of severe acute hepatitis or acute liver failure caused by taking irusadolin. Probability score: C (likely a cause of acute liver injury, possibly due to bile duct spasm or obstruction). Effects during pregnancy and lactation: ◉ Overview of use during lactation: There is currently no information regarding the use of irusadolin during lactation. Due to its opioid agonist activity, the use of other medications is recommended, especially in breastfed newborns or premature infants. ◉ Effects on breastfed infants: No relevant published information was found as of the revision date. ◉ Effects on lactation and breast milk: No relevant published information was found as of the revision date.

---

Protein binding rate
81%

[1]. Pharmaceutics. 2023 May 10;15(5):1460.

Elushadolin is an amino acid amide formed by the condensation of the carboxyl group of 4-carbamoyl-2,6-dimethyl-L-phenylalanine and the secondary amino group of 2-methoxy-5-({[(1S)-1-(4-phenylimidazol-2-yl)ethyl]amino}methyl)benzoic acid. It possesses mixed opioid receptor activity and is used to treat diarrhea-predominant irritable bowel syndrome. It can function as a μ-opioid receptor agonist, δ-opioid receptor antagonist, κ-opioid receptor agonist, and gastrointestinal drug. It belongs to the imidazole, methoxybenzoic acid, benzamide, L-phenylalanine derivative, and amino acid amide classes. Elushadolin is a Category IV controlled substance under the U.S. Drug Enforcement Administration (DEA). Compared to Category III controlled substances, Category IV controlled substances have a lower potential for abuse. It belongs to the Others category. Elushadolin is a mixed-action μ-opioid receptor agonist, κ-opioid receptor agonist, and α-δ-opioid receptor antagonist indicated for diarrhea-predominant irritable bowel syndrome (IBS-D). μ, κ, and δ-opioid receptors mediate endogenous and exogenous opioid responses in the central nervous system and peripheral gastrointestinal system. Peripheral μ-opioid receptor agonists reduce colonic motility, while central δ-opioid receptor antagonists enhance analgesia; therefore, elushadolin can be used to relieve pain and diarrhea symptoms in IBS-D. Elushadolin (brand name: Viberzi, FDA approved) is an antidiarrheal medication that reduces intestinal motility, inhibits colonic transit, and reduces fluid/ion secretion, thereby improving abdominal pain symptoms and lowering the Bristol stool classification score. Elushadolin is a μ-opioid receptor agonist. Its mechanism of action is as a μ-opioid receptor agonist. Eloxadolin is a mixed-type opioid receptor agonist (μ) and antagonist (δ) used to treat irritable bowel syndrome (IBS) with diarrhea as the predominant symptom. Eloxadolin is associated with a lower incidence of elevated serum transaminases, which appears to be due to occasional sphincter of Oddi spasm and/or pancreatitis, most commonly seen in patients without a gallbladder.

---

Drug Indications
For the treatment of diarrhea-predominant Irritable Bowel Syndrome (IBS-D).
FDA Label
Truberzi is indicated for the treatment of diarrhea-predominant IBS-D in adults.
Truberzi Treatment of Diarrhea-Predominant IBS

---

Mechanism of Action
Eloxadolin is a μ-opioid receptor agonist, κ-opioid receptor agonist, and δ-opioid receptor antagonist. Eloxadolin is used to treat diarrhea-predominant IBS because it reduces intestinal contractility and accelerates the return to normal of stress-induced upper gastrointestinal transit. Its antagonistic effect on delta receptors minimizes the constipation side effect that is commonly seen when μ-opioid receptor agonists are used alone. Due to its limited systemic bioavailability, erusadolin may have fewer side effects compared to other therapies used to treat diarrhea-predominant IBS.

C32H35N5O5

569.66

569.263

C, 67.47; H, 6.19; N, 12.29; O, 14.04

864821-90-9

864825-13-8 (HCl);864821-90-9;

11250029

Solid powder

1.3±0.1 g/cm3

834.2±65.0 °C at 760 mmHg

458.3±34.3 °C

0.0±3.2 mmHg at 25°C

1.640

4.35

4

7

11

42

917

2

N(C(=O)[C@@H](N)CC1C(C)=CC(C(=O)N)=CC=1C)(CC1C=CC(OC)=C(C(=O)O)C=1)[C@H](C1=NC=C(C2C=CC=CC=2)N1)C

QFNHIDANIVGXPE-FNZWTVRRSA-N

InChI=1S/C32H35N5O5/c1-18-12-23(29(34)38)13-19(2)24(18)15-26(33)31(39)37(17-21-10-11-28(42-4)25(14-21)32(40)41)20(3)30-35-16-27(36-30)22-8-6-5-7-9-22/h5-14,16,20,26H,15,17,33H2,1-4H3,(H2,34,38)(H,35,36)(H,40,41)/t20-,26-/m0/s1

5-(((S)-2-amino-3-(4-carbamoyl-2,6-dimethylphenyl)-N-((S)-1-(5-phenyl-1H-imidazol-2-yl)ethyl)propanamido)methyl)-2-methoxybenzoic acid

JNJ 27018966; JNJ27018966; JNJ-27018966; Trade name: Viberzi

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

---

Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

View More

Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

---

Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

View More

Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

---

Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

---

 (Please use freshly prepared in vivo formulations for optimal results.)