High-Performance Liquid Chromatography (HPLC) Method Validation for Identifying and Quantifying Rebamipide in Ethosomes

Introduction The research aimed to develop a robust, high-performance liquid chromatography (HPLC) analytical method for the quantitative assessment of rebamipide encapsulated in ethosomes. Rebamipide, a quinolinone derivative, holds promise as a therapeutic agent for dry eye, but challenges such as low bioavailability and vision clouding post-installation have prompted innovative approaches. Encapsulation in ethosomes, lipid-based nanovesicles, offers a potential solution to enhance ocular bioavailability. Materials and methods The study focused on creating a specific, linear, accurate, precise, and robust HPLC method, addressing entrapment efficiency (%EE), drug content, and drug release of rebamipide in prepared ethosomes. Statistical validation followed International Conference of Harmonization (ICH) specifications. The method's parameters were evaluated within a concentration range of 4-24 µg/ml, with recovery rates indicating accuracy and low % relative standard deviation (RSD) values confirming precision. Limits of detection (LOD) and quantification (LOQ) for rebamipide were determined. Results After preparing the ethosome dosage form by film hydrating method for rebamipide, the rebamipide entrapment efficiency in ethosomes was established at 76% ± 7, while the drug content was found to be 93% ± 6. The drug release process demonstrated zero-order kinetics and five different models of kinetics were applied for a comprehensive analysis. The method exhibited excellent system suitability, specificity, and linearity. Recovery rates for rebamipide ranged from 90% to 100%, and repeatability was confirmed by low %RSD values. The LOD and LOQ for rebamipide were determined to be 1.04 μg/mL and 3.16 μg/mL, respectively. Conclusion The developed HPLC method proved suitable for the quantitative determination of rebamipide in ethosomes, offering rapid and accurate analysis. The results underscore the method's specificity, accuracy, and precision within the specified concentration range. Overall, the validated method contributes to the advancement of ocular drug delivery systems, providing a reliable analytical tool for pharmaceutical research.

Further insights into the impact of rebamipide on gentamicin-induced nephrotoxicity in rats: modulation of SIRT1 and β-catenin/cyclin D1 pathways

Gentamicin (GM) is an effective antibiotic administered to treat acute Gram-negative infections. Nevertheless, its clinical application is limited due to nephrotoxicity. Therefore, our research aimed to investigate the potential renoprotective impact of rebamipide (RBM), a gastroprotective drug, on GM-induced kidney damage in rats, as well as putative nephroprotective pathways. RBM was orally administered (100 mg/kg/d for 14 d) commencing 7 d before the administration of GM (100 mg/kg/d, intraperitoneally). Nephrotoxicity was elucidated, and the silent information regulator 1 (SIRT1) and β-catenin/cyclin D1 pathways were assessed. GM induced a significant elevation in the serum levels of creatinine, blood urea nitrogen (BUN), and kidney injury molecule-1 (KIM-1), as well as the relative kidney index. In addition, GM increased lipid peroxidation and lowered total antioxidant capacity (TAC) level and superoxide dismutase (SOD) activity. GM administration also demonstrated a significant amplification in tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), nuclear factor-κappa B p65 (NF-κB p65), p38 mitogen-activated protein kinase (p38 MAPK), and caspase-3 kidney levels, as well as B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax)/Bcl-2 ratio. Notably, RBM treatment amended all these changes induced by GM. Furthermore, the potential role of SIRT1 and β-catenin-dependent signaling pathways in GM-induced renal injury was assessed. Our findings showed that GM-treated rats demonstrated a substantial decrease in SIRT1, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) along with an increase in β-catenin, forkhead box O-3a (FOXO-3a), and cyclin D1 protein expressions. RMB treatment markedly attenuated the deterioration caused by GM on these pathways. Additionally, RBM alleviated the GM-induced deleterious kidney tissue histopathology. In conclusion, our findings have verified that RBM can halt GM-induced renal injury by partly modulating SIRT1 and β-catenin pathways.

Efficacy and safety of topical 2% rebamipide ophthalmic suspension in dry eye disease at tertiary care centre

Purpose

To evaluate the effect and side effects of topical 2% rebamipide ophthalmic suspension in dry eye disease.

Method

This prospective randomized case control study included total 80 patients (40 cases and 40 controls) of dry eye. Symptoms were graded according to OSDI scoring system and specific tests for dry eye included Tear film breakup time (TBUT), Schirmer's test, Fluorescein corneal staining (FCS), Rose Bengal staining) were performed. Case group received 2% rebamipide ophthalmic suspension four times daily and control group given carboxymethylcellulose 0.5% four times daily. The follow ups had done at two, six and twelve weeks.

Results

The maximum numbers of patients were between 45-60 years. Patient with mild moderate and severe OSDI Score shows marked improvement. Mild TBUT score showed improvement but statistically not significant (P value-0.34). In moderate and severe TBUT Score statistically significant improvement (P value- 0.0001, 0.0001). In all grade FCS shows statistically significant improvement with p value-0.0001, 0.0001, and 0.028 respectively. Schirmer's test score in all cases had shown improvement but statistically not significant and P value were 0.09, 0.07, and 0.07 respectively. In mild, moderate and severe Rose Bengal staining statistically significant improvement (P value -0.027, 0.0001, and 0.04) .The only side effect was dysgeusia (10% patients).

Conclusion

Rebamipide 2% ophthalmic suspension showed significant improvement in symptoms and signs of dry eye. It able to modify epithelial cell function, improve tear stability, and suppress inflammation suggests that it may be a first drug of choice for severe dry eye disease.

[Pharmacokinetics and pharmacodynamics of rebamipide. New possibilities of therapy: A review]

The MedLine database contains 570 publications, including 71 randomized clinical trials and 6 meta-analyses on the rebamipide molecule in 2022. Indications for the use of rebamipide are gastric ulcer, chronic gastritis with hyperacidityin the acute stage, erosive gastritis, prevention of damage to the gastrointestinal mucosa while taking non-steroidal anti-inflammatory drugs, eradication of Helicobacter pylori. Currently trials are studying the efficacy and safety of the drug in gouty and rheumatoid arthritis, osteoarthritis, Sjögren's syndrome, bronchial asthma, vitiligo, atherosclerosis, diseases of the kidneys and liver; using in traumatology to accelerate bone regeneration; in ophthalmology to improve the regeneration of corneal epithelium; in oncology to reduce inflammatory changes in the oral mucosa after chemoradiotherapy. The review article is about the main pharmacokinetic and pharmacodynamic characteristics of rebamipide. A detailed understanding of pharmacodynamics and pharmacokinetics allows for individual selection of therapy based on the characteristics of the patient's body - gender, age, comorbidities; choose the optimal route of administration and dosing regimen; predict adverse effects and drug interactions; be determined with new clinical indications.

Intra-Articular Injection of Rebamipide-Loaded Nanoparticles Attenuate Disease Progression and Joint Destruction in Osteoarthritis Rat Model: A Pilot Study

OBJECTIVE

Rebamipide has antioxidant effects and is a drug with a local rather than systemic mechanism of action. Oxidative stress and inflammation in chondrocytes are the major factors contributing to the development and progression of osteoarthritis (OA). Since OA is mainly developed in weight bearing or overused joints, the locally sustained therapy is effective for targeting inflammatory component of OA. We investigated the effects of intra-articular injection of rebamipide loaded nanoparticles (NPs) in OA rat model.

DESIGN

We fabricated rebamipide-loaded methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (mPEG-PDLLA) and poly(D, L-lactide-co-glycolide) (PLGA) NPs that allow the sustained release of rebamipide. In vitro, chondrocytes from rat were used to investigate the cytotoxicity and anti-inflammatory effect of rebamipide-loaded NPs. In vivo, monosodium iodoacetate (MIA)-induced OA rats were divided into 7 groups, consisting of healthy control rats and rats injected with MIA alone or in combination with NPs, rebamipide (1 mg)/NPs, rebamipide (10 mg)/NPs, rebamipide (10 mg) solution, or oral administration.

RESULTS

In vitro, rebamipide/NPs dose-dependently suppressed the mRNA levels of pro-inflammatory mediators, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, matrix metalloproteinase (MMP)-3, MMP-13, and cyclo-oxygenase-2. In vivo, the mRNA levels of pro-inflammatory components most markedly decreased in the intra-articularly injected rebamipide (10 mg)/NP group compared to other groups. Macroscopic, radiographic, and histological evaluations showed that the intra-articular injection of rebamipide/NPs inhibited cartilage degeneration more than rebamipide solution or rebamipide administration.

CONCLUSIONS

Using a chemically induced rat model of OA, intra-articular delivery of rebamipide was associated with decreased local and systemic inflammatory response decreased joint degradation and arthritic progression.

The risk of pulmonary adverse drug reactions of rebamipide and other drugs for acid-related diseases: An analysis of the national pharmacovigilance database in South Korea

OBJECTIVE

The objective of this case/non-case study was to detect rebamipide-related pulmonary adverse events (AE) compared with other drugs for acid-related disorders based on population-level data.

METHODS

From 2009 to 2018, AE reports on drugs for acid-related disorders, which are anatomical therapeutic chemical code A02B drugs, in the Korea Adverse Events Reporting System (KAERS) database were examined. The reporting odds ratio (ROR) was calculated, and the odds of reporting pulmonary AE for rebamipide and all other A02B drugs were compared. Furthermore, a stratified analysis according to patients' age and sex was conducted.

RESULTS

Altogether 13 (0.05%) and 157 (0.11%) cases of pulmonary AE were reported for rebamipide and all other A02B drugs, respectively. The risk of reporting pulmonary AE was significantly lower for rebamipide than for all other A02B drugs (ROR 0.49, 95% confidence interval [CI] 0.28-0.87). The number of reports of pulmonary AE for rebamipide was significantly higher among patients aged ≥65 years than those aged <65 years (ROR 19.36, 95% CI 2.50-149.97).

CONCLUSIONS

Rebamipide was less often reported for pulmonary AE. However, healthcare professionals need to be aware of the risk of pulmonary AE in elderly patients.

Effect of Rabeprazole and Rebamipide in the Treatment of Upper Gastrointestinal Hemorrhage Associated with Dual Antiplatelet Therapy in Elderly Patients with Coronary Heart Disease

To investigate the therapeutic effect of rabeprazole and rebamipide on patient age over 60 with dual antiplatelet therapy (DAPT)-related upper gastrointestinal hemorrhage following percutaneous coronary intervention (PCI). A total of 360 patients age over 60 undergoing PCI were recruited for antiplatelet therapy involving a combined treatment of aspirin (100 mg/d) and clopidogrel (75 mg/d). The enrolled patients were divided into 4 groups: the control group, the rabeprazole group, the rebamipide group, and the rabeprazole + rebamipide group. The incidence and severity of any upper gastrointestinal hemorrhage and the incidence of major adverse cardiac events (MACEs) were observed 6 months after the operation. The incidence of upper gastrointestinal hemorrhage in the 4 groups was 11.1%, 3.3%, 8.9%, and 1.1%, respectively, and the differences were statistically significant (P < 0.05). On comparing the groups, the differences between the control group and the rabeprazole group, those between the control group and the rabeprazole + rebamipide group, and those between the rebamipide group and the rabeprazole + rebamipide group were found to be statistically significant (P < 0.05). The severity of the upper gastrointestinal hemorrhage in the rabeprazole group and the rabeprazole + rebamipide group was significantly lower than that in the control group. The 4 groups exhibited no significant differences in the incidence of MACEs (P > 0.05). For patients age over 60 receiving DAPT following PCI in our study population, treatment with rabeprazole or a combination of rabeprazole and rebamipide could reduce the risk of upper gastrointestinal hemorrhage, as well as reduce its severity.

Preparation and Evaluation of a Powdered Rebamipide Mouthwash as In-Hospital Formulation: Considering Dispersion before Use in Patients

In Japan, rebamipide (RB) mouthwash (RB-MW) for oral mucositis induced by cancer chemotherapy has been prepared using in-hospital formulation. Usually, RB-MW is prepared by dispersing crushed commercial RB tablets in the dispersion medium; however, uniformity is difficult to obtain due to low solubility. The current study aims is to prepare homogenously dispersed formulations using the fine particles of crushed tablets by a method that is convenient for hospital use. Commercial RB tablets were pre-milled at different milling times as "RB-Ts". A ground mixture was then prepared by co-grinding the RB-Ts with HPC-L or PVP K30 via a benchtop ball milling machine (MM400). The physicochemical properties of samples were evaluated for PXRD, FTIR, turbidity, particle size, and solubility. Although the milling of RB tablets decreased the crystallinity, the length of milling time did not affect them. In contrast, grinding using MM400 significantly decreased RB crystallinity; their PXRD patterns showed a halo, suggesting the amorphization of RB crystals by grinding. Although solubility and turbidity seemed to be affected by the type of polymer rather than the particle size, every ground mixture showed high dispersibility. Thus, grinding the RB-Ts with polymers appeared to be the most promising way to obtain stable dispersion as an in-hospital formulation.

Efficacy of 2% Rebamipide Suspension for Vernal Keratoconjunctivitis: A Clinical Comparison with Topical Immune Modulators Cyclosporine and Tacrolimus

Purpose: To compare the efficacy of 2% rebamipide suspension with topical cyclosporine and tacrolimus for managing vernal keratoconjunctivitis (VKC)Methods: In this prospective, interventional study, 38 patients with moderate to severe VKC were allocated to receive either 2% rebamipide in one eye and 0.03% tacrolimus ointment in the contralateral eye (n = 19) or 2% rebamipide in one eye and 0.05% cyclosporine in the contralateral eye (n = 19) for 12 weeks. Ten ocular signs and 7 symptoms were graded on a scale of 0-3 each for each eye at every visit.Results: Total sign and symptom scores reduced significantly in all 4 subgroups (all p's <0.05) at 12 weeks. Reduction of mean sign scores between rebamipide and tacrolimus (- 4.67 ± 4.63 and - 2.80 ± 3.18 respectively) and between rebamipide and cyclosporine (-6.00 ± 3.74 and -5.42 ± 3.68 respectively) was comparable. Reduction in symptom scores was also comparable between subgroups.Conclusion: Our findings suggest that efficacy of topical rebamipide is comparable to topical cyclosporine and tacrolimus for managing moderate to severe VKC and it merits further evaluation as a novel steroid sparing alternative for this disorder.

Rebamipide potentially mitigates methotrexate-induced nephrotoxicity via inhibition of oxidative stress and inflammation: A molecular and histochemical study

Methotrexate (MTX) is a widely used chemotherapeutic agent; nevertheless, the nephrotoxicity associated with its use has limited its clinical use. Rebamipide (REB) is a gastro-protective agent with diverse promising biological activities. Here, we investigated the renoprotective effects of REB against MTX-induced nephrotoxicity in rats. Male Wistar rats were allocated into four groups: the normal control group, the REB group (100 mg kg^-1 day^-1 , PO, for 12 days), the MTX group (which received a single injection of 20 mg/kg, ip), and the REB + MTX group (which received 100 mg kg^-1 day^-1 REB for 7 days before and 5 days after being injected with 20 mg/kg MTX). Interestingly, MTX triggered kidney injury, characterized by renal dysfunction along with histopathological alterations. Moreover, increased reactive oxygen species level and inflammatory response were detected in the kidney of MTX-treated rats. However, REB prevented MTX-induced oxidative kidney injury and boosted an antioxidant balance. Mechanistically, REB markedly activated the NRF-2 protein and upregulated the expression of both SIRT-1 and FOXO-3 genes. Additionally, REB administration strongly inhibited the inflammatory response by downregulating both NF-κB-p65 and TLR-4. Finally, the coadministration of REB and MTX activated the mTOR/PI3K/AKT signaling pathway. Simultaneously, REB treatment attenuated the reduction in glomerular size, the widening of the capsular spaces, and the tubular cell damage due to MTX administration. Taken together, these results indicate the potential of REB as adjuvant therapy to prevent nephrotoxicity in patients receiving MTX treatment.

[Rebamipide: evidence base for use in gastroenterology]

Rebamipide is a cytoprotective drug that has been used in practical gastroenterology for 30 years. This article summarizes the main results of the most relevant clinical studies of rebamipide in diseases of various parts of the gastrointestinal tract, including the esophagus, stomach, small and large intestine.

[A new approach to understanding the pathogenesis and treatment of infectious and inflammatory diseases of the urogenital tract]

The current trends in understanding the pathogenesis of infectious and inflammatory urogenital disorders are highlighted in the review. The etiological and pathogenetic significance of increased intestinal permeability for pathogens in the development of various diseases has been convincedly proved. There is no doubt about the pathogenetic role of increased permeability of the bladder mucosa, which can result in interstitial cystitis (IC). The association of intestinal diseases with IC has been established. In rats, the induction of intestinal inflammation may cause increased permeability of the bladder mucosa. In the postoperative period, bacteria are translocated from the gastrointestinal tract to the urinary tract, which is associated with stress. Particular attention is paid to the therapy based on new knowledge about the pathogenesis of infectious and inflammatory diseases of the urogenital tract. Possibilities of decreasing intestinal and bladder permeability using rebamipide are described. Various therapeutic mechanisms of action made it possible to use this drug in endoscopy, ophthalmology, chemotherapy and rheumatology. The antioxidant and anti-inflammatory properties of rebamipide has been shown in-vitro. Intravesical instillation of rebamipide accelerates the recovery of damaged urothelium and its barrier function, and also influences on bladder hyperactivity. Thus, the first results of using rebamipide in urology are encouraging; however, further researches are required.

Effect of Polymers and Storage Relative Humidity on Amorphous Rebamipide and Its Solid Dispersion Transformation: Multiple Spectra Chemometrics of Powder X-Ray Diffraction and Near-Infrared Spectroscopy

This study aimed to investigate the effect of polymers and storage relative humidity on amorphous rebamipide (RB) and its solid dispersion phase transformation using chemometrics based on multiple datasets. The amorphous RB was prepared using particle mixture and grinding methods with hydroxypropyl cellulose, polyvinylpyrrolidone, and sodium dodecyl sulfate. Prepared amorphous RB and solid dispersion samples were stored under a relative humidity of 30% and 75% for four weeks. Infrared spectra of the dispersion samples suggested that the hydrogen bond network was constructed among quinolinone, carbonyl acid, and amide of RB and other polymers. The dataset combining near-infrared (NIR) spectra and powder X-ray diffractograms were applied to principal component analysis (PCA). The relationship between diffractograms and NIR spectra was evaluated using loadings and the PCA score. The multiple spectra analysis is useful for evaluating model amorphous active pharmaceutical ingredients without a standard sample.

Interspecies differences on pharmacokinetics of rebamipide following oral administration to rats and dogs

Rebamipide is used widely in East Asia for the treatment of gastric ulcers, acute gastritis, and exacerbated chronic gastritis. The objective of this study was to investigate the pharmacokinetic (PK) properties of rebamipide following single oral administration in rats and dogs. Eleven rats and dogs received single oral administrations of rebamipide (35 mg/kg and 100 mg, respectively). Blood samples were collected according to the assigned schedule, and the plasma concentration of rebamipide was determined using liquid chromatography-tandem mass spectrometry. A double-peak phenomenon was observed in the PK profile of rebamipide in rats. In contrast, rebamipide showed a conventional PK profile without double peaks in dogs. The half-life of rebamipide in rats (12.85 ± 7.86 h) was longer than that in dogs (5.62 ± 2.24 h), and the apparent total clearance (Cl_t /F) of rebamipide in rats (3.32 ± 1.18 L/h) was lower than that in dogs (105.01 ± 42.37 L/h). Simple allometric approaches showed that the correlation between body weight and Cl_t /F (R² = 0.9287) among rats, dogs, and humans appeared satisfactory. This finding will help not only in understanding the pharmacology of rebamipide but also in establishing a strategy for in vivo evaluation of novel rebamipide formulations.

Effects of rebamipide for chronic atrophic gastritis: A protocol for systematic review and meta-analysis

BACKGROUND

Chronic atrophic gastritis (CAG) is defined as an important precancerous disease with high risk of gastric cancer. Rebamipide is a mucosal protective agent widely used in the treatment of chronic gastritis. The aim of this systematic review is to assess the efficacy and safety of rebamipide for the treatment of patients with CAG.

METHODS AND ANALYSIS

We will perform a comprehensive retrieval in the following electronic databases: PubMed, Embase, MEDLINE, Cochrane Library Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI) database, Wanfang Data Knowledge Service Platform, Chinese Scientific Journals Database (VIP), Chinese Biomedical Literature Service System (SinoMed) and other sources. Two trained researchers will select the qualified studies for data extraction and assess the quality and risk of bias, independently. Then the meta-analyses will be conducted by using the RevMan 5.2 and stata 14.0. The heterogeneity of data will be investigated by Cochrane X and I tests. Sensitivity analysis will be conducted to evaluate the stability of the results. Funnel plot analysis and Egger test will be used to assess the publication bias. Finally, the quality of evidence will be assessed by the GRADE system.

RESULTS

The results of our research will be published in a peer-reviewed journal.

CONCLUSION

The conclusion of our systematic review will provide evidence to judge whether rebamipide is an effective intervention for patient with CAG.

OSF REGISTRATION NUMBER

10.17605/OSF.IO/BKC3E.

Hydrogel Formulations Incorporating Drug Nanocrystals Enhance the Therapeutic Effect of Rebamipide in a Hamster Model for Oral Mucositis

A mouthwash formulation of rebamipide (REB) is commonly used to treat oral mucositis; however, this formulation does not provide sufficient treatment or prevention in cases of serious oral mucositis. To improve treatment, we attempted to design a hydrogel incorporating REB nanocrystals (R-NPs gel). The R-NPs gel was prepared by a bead mill method using carbopol hydrogel, methylcellulose and 2-hydroxypropyl-β-cyclodextrin, and another hydrogel incorporating REB microcrystals (R-MPs gel) was prepared following the same protocol but without the bead mill treatment. The REB particle size in the R-MPs gel was 0.15–25 μm, and while the REB particle size was 50–180 nm in the R-NPs gel. Next, we investigated the therapeutic effect of REB nanocrystals on oral mucositis using a hamster model. Almost all of the REB was released as drug nanocrystals from the R-NPs gel, and the REB content in the cheek pouch of hamsters treated with R-NPs gel was significantly higher than that of hamsters treated with R-MPs gel. Further, treatment with REB hydrogels enhanced the healing of oral wounds in the hamsters. REB accumulation in the cheek pouch of hamsters treated with the R-NPs gel was prevented by an inhibitor of clathrin-dependent endocytosis (CME) (40 μM dynasore). In conclusion, we designed an R-NPs gel and found that REB nanocrystals are taken up by tissues through CME, where they provide a persistent effect resulting in an enhancement of oral wound healing.

Novel Sustained-Release Drug Delivery System for Dry Eye Therapy by Rebamipide Nanoparticles

The commercially available rebamipide ophthalmic suspension (CA-REB) was approved for clinical use in patients with dry eye; however, the residence time on the ocular surface for the traditional formulations is short, since the drug is removed from the ocular surface through the nasolacrimal duct. In this study, we designed a novel sustained-release drug delivery system (DDS) for dry eye therapy by rebamipide nanoparticles. The rebamipide solid nanoparticle-based ophthalmic formulation (REB-NPs) was prepared by a bead mill using additives (2-hydroxypropyl-β-cyclodextrin and methylcellulose) and a gel base (carbopol). The rebamipide particles formed are ellipsoid, with a particle size in the range of 40-200 nm. The rebamipide in the REB-NPs applied to eyelids was delivered into the lacrimal fluid through the meibomian glands, and sustained drug release was observed in comparison with CA-REB. Moreover, the REB-NPs increased the mucin levels in the lacrimal fluid and healed tear film breakup levels in an N-acetylcysteine-treated rabbit model. The information about this novel DDS route and creation of a nano-formulation can be used to design further studies aimed at therapy for dry eye.

Rebamipide-containing Film Using Chitosan and HPMC for Oral Mucositis Induced by Cancer Chemotherapy

BACKGROUND/AIM

Oral mucositis is a significant side effect in cancer treatment. In this study, we aimed to develop a rebamipide-containing film using chitosan and hydroxypropyl methylcellulose (HPMC) to efficiently treat oral mucositis.

MATERIALS AND METHODS

A 0.1% (w/v) rebamipide aqueous solution, a 1.4% (w/v) chitosan aqueous solution containing Pluronic® F-127, and a 1.0% (w/v) HPMC aqueous solution were mixed and dried using a square silicon frame to form a film. Cumulative release ratios of rebamipide from sample films were measured in a phosphate buffer (pH 6.8) at 37°C.

RESULTS

Chitosan suppressed the release of rebamipide from the film for up to 30 min. HPMC contributed to the sustained release of the film over a relatively long period of time and the maintenance of its shape.

CONCLUSION

The combined use of chitosan and HPMC is suitable as a base material for rebamipide-containing films.

Reactions of Rebamipide with Hypobromous Acid

Rebamipide is a therapeutic agent for gastric ulcers and chronic gastritis. Hypobromous acid (HOBr) is generated not only by eosinophils but also by neutrophils in the presence of bromide ions in the plasma. At inflammation sites, rebamipide may encounter and react with HOBr to generated various products. When rebamipide was incubated with reagent HOBr in potassium phosphate buffer at pH 4.7 and 37°C for 4 h, several products were generated. A major product was identified as 3-bromorebamipide, a novel compound. Rebamipide does not react with hypochlorous acid (HOCl). However, when rebamipide was incubated with HOCl in the presence of NaBr, 3-bromorebamipide was generated in a dose-dependent manner, probably because of formation of HOBr. These results suggest that 3-bromorebamipide may generate from rebamipide at inflammation sites in humans.

Solid Nanocrystals of Rebamipide Promote Recovery from Indomethacin-Induced Gastrointestinal Bleeding

Indomethacin (IMC)-induced gastrointestinal (GI) injuries are more common in rheumatoid arthritis (RA) patients than in other IMC users, and the overexpression of nitric oxide (NO) via inducible NO synthase (iNOS) is related to the seriousness of IMC-induced GI injuries. However, sufficient strategies to prevent IMC-induced GI injuries have not yet been established. In this study, we designed dispersions of rebamipide (RBM) solid nanocrystals (particle size: 30–190 nm) by a bead mill method (RBM-NDs), and investigated whether the oral administration of RBM-NDs is useful to prevent IMC-induced GI injuries. The RBM nanocrystals were spherical and had a solubility 4.71-fold greater than dispersions of traditional RBM powder (RBM-TDs). In addition, the RBM-NDs were stable for 1 month after preparation. The RBM contents in the stomach, jejunum, and ileum of rats orally administered RBM-NDs were significantly higher than in rats administered RBM-TDs. Moreover, the oral administration of RBM-NDs decreased the NO levels via iNOS and area of the GI lesions in IMC-stimulated RA (adjuvant-induced arthritis rat) rats in comparison with the oral administration of RBM-TDs. Thus, we show that the oral administration of RBM-NDs provides a high drug supply to the GI mucosa, resulting in a therapeutic effect on IMC-induced GI injuries. Solid nanocrystalline RBM preparations may offer effective therapy for RA patients.

Efficiency of the Inclusion of Rebamipide in the Eradication Therapy for Helicobacter pylori Infection: Meta-Analysis of Randomized Controlled Studies

Background: There has been a negative trend in the effectiveness of classic eradication therapy regimens for Helicobacter pylori (H. pylori), which has largely been determined from the emergence and spread of antibiotic resistance. Several studies have shown that adding rebamipide to eradication regimens leads to an increase in the effectiveness of treatment. Aim: To evaluate the efficacy and safety of including rebamipide in the eradication regimens for H. pylori infection. Methods: The literature search was conducted in the MEDLINE/PubMed, EMBASE, Cochrane Central Register, Korean Medical Citation Index, and Russian Science Citation Index databases. All identified randomized controlled trials comparing rebamipide supplementation with non-rebamipide-containing eradication regimens for the treatment of H. pylori infection were included in the final analysis. Results: We identified 11 randomized controlled trials (RCTs) involving 1227 patients (631 in groups with rebamipide and 596 in groups without rebamipide). The meta-analysis showed that the addition of rebamipide to eradication regimens significantly increased the effectiveness of treatment (odds ratio (OR) 1.753, 95% confidence interval (CI) 1.312–2.333, p < 0.001). The subgroup analysis demonstrated that rebamipide significantly increased the effectiveness of eradication when added to a dual therapy regimen (OR 1.766, 95% CI: 1.167–2.495, p = 0.006); however, no significant improvement in effectiveness was observed when it was added to the triple therapy regimen (OR 1.638, 95% CI 0.833–3.219, p = 0.152). Conclusion: This meta-analysis demonstrated that the addition of rebamipide to H. pylori eradication regimens significantly increases the effectiveness of treatment.

The Effects of Rebamipide 2% Ophthalmic Solution Application on Murine Subbasal Corneal Nerves After Environmental Dry Eye Stress

Rebamipide ophthalmic solution is a mucin secretagogue which is an important therapeutic agent in the treatment of dry eye. It has been noted that dry eye in office workers is associated with a decrease in secretory mucin. This study aimed to evaluate the effects of 2% rebamipide ophthalmic solution in mice subjected to environmental dry eye stress (EDES), which mimics the conditions of office workers. Thirty eyes from thirty BALB/c mice (eight-week-old males) were divided into three treatment groups: artificial tear (vehicle), 2% rebamipide ophthalmic solution, and 0.1% hyaluronic acid (HA) ophthalmic solution. After four days of pretreatment, mice were exposed to EDES for three days. The corneal subbasal nerve and inflammatory cells were then examined using in vivo confocal microscopy. Following EDES exposure, the lissamine green staining score was significantly lower and corneal sensitivity was more preserved in the 2% rebamipide group than in the HA group. In addition, the subbasal nerve fiber density was significantly higher and the DC density was significantly lower in the 2% rebamipide group than in the HA group. Overall, the topical rebamipide ophthalmic solution showed more favorable therapeutic effects when compared to the HA ophthalmic solution in a mouse model of EDES, likely owing to its anti-inflammatory and neuroprotective effects.

Intra-articular injection of rebamipide prevents articular cartilage degeneration in murine post-traumatic osteoarthritis models

Objectives: Rebamipide is a protective drug used for gastric mucosal injuries, and it also exerts protective effects for a variety of other tissues. In this study, murine post-traumatic (PT) osteoarthritis (OA) models in vivo and human OA chondrocytes in vitro were used to examine the effects of rebamipide on articular cartilage degeneration.Methods: Male BALB/c mice were used. The knee ligaments were transected in both knees. Mice were injected with rebamipide into the knee joint every week. Human chondrocytes were stimulated with IL-1β, then treated with or without rebamipide. The levels of mRNA expression of COL2A, IL-1β, TNFα, NF-κB, MMP3, MMP13, ADAMTS5, TIMP3, FGF2, and TGFβ were estimated using real-time PCR.Results: Histological scores were significantly better in the rebamipide 1 mg/mL and 10 mg/mL groups than in the control group. Rebamipide up-regulated the mRNA expressions of COL2A, TIMP3, TGFβ, and FGF2 in chondrocytes and down-regulated IL-1β, TNFα, NF-κB, MMP3, MMP13, and ADAMTS5.Conclusion: Intra-articular injection of rebamipide prevents articular cartilage degeneration for 6 weeks in murine models of OA in vivo. Rebamipide down-regulates inflammatory cytokines and catabolic factors and up-regulates anabolic factors in human chondrocytes in vitro. Rebamipide could be an important treatment for prevention of articular cartilage degeneration.

The Efficacy of 2% Topical Rebamipide on Conjunctival Squamous Metaplasia and Goblet Cell Density in Dry Eye Disease

Purpose: To clarify the pharmacological effects of 2% rebamipide eye drops on mucosal membrane functions of the ocular surface epithelium, we investigated keratoconjunctival alterations at the cellular level in this study.

Methods: Fifteen patients with definite dry eye disease were recruited from outpatient clinics of the Department of Ophthalmology, Ichikawa General Hospital. The patients received treatment with 2% rebamipide eye drops q.i.d for 12 weeks. Symptom score assessment, tear film breakup time, fluorescein and lissamine green ocular surface vital staining, grading of lid wiper epitheliopathy, Cochet–Bonnet corneal sensitivity, assessment of squamous metaplasia grades, and goblet cell density calculations from conjunctival impression cytology samples, as well as evaluation of nucleocytoplasmic ratios and corneal epithelial cells from in vivo confocal microscopy images before and 3 months after treatment were performed.

Results: The mean symptom scores, tear film breakup time values, ocular surface fluorescein and lissamine green vital staining scores, and lid wiper scores showed a significant improvement after treatment (P < 0.01). The mean squamous metaplasia grade also showed a significant improvement (1.2 ± 0.1 → 0.3 ± 0.1) 3 months after treatment (P = 0.004). There were similar significant improvements in the mean corneal epithelial cell density (660.1 ± 62.6 → 1015.5 ± 43.5 cells/mm²) (P = 0.002) and nucleocytoplasmic ratios (0.1 ± 0.0 → 0.2 ± 0.0) (P = 0.0042) after treatment.

Conclusions: Topical use of 2% rebamipide for 3 months was associated with improvements in ocular surface differentiation due to changes of mucosal functions at the cellular level. These alterations may explain objective and subjective improvements in dry eye disease.

Rebamipide ophthalmic solution modulates the ratio of T helper cell 17/regulatory T cells in dry eye disease mice

The aim of the present study was to confirm the effect of 2% rebamipide ophthalmic solution on a scopolamine‑induced dry eye (DE) mouse model, and to investigate its effect on the ratio of T helper cell 17 (Th17)/regulatory T cell (Treg) numbers. C57BL/6 mice received subcutaneous injections of scopolamine and were exposed to a low‑humidity environment in order to establish a DE model. Rebamipide eye drops (2%) administered four times daily for 2 weeks, significantly reduced the corneal staining scores and increased the tear film breakup time and tear production in the DE mice. Pathologically, the rebamipide restored the histological changes induced by DE in the cornea, conjunctiva and lacrimal gland. At a molecular level, it downregulated pro‑inflammatory and upregulated anti‑inflammatory cytokines in the conjunctiva and lacrimal gland. Furthermore, the increased Th17 and Treg levels were restored following treatment with rebamipide. In conclusion, the anti‑inflammatory and Th17/Treg balance‑preserving effects of rebamipide may contribute to the treatment of DE in mice.

Characterization of Amorphous Solid Dispersion of Pharmaceutical Compound with pH-Dependent Solubility Prepared by Continuous-Spray Granulator

A continuous-spray granulator (CTS-SGR) is a one-step granulation technology capable of using solutions or suspensions. The present research objectives were, (1) to reduce the manufacturing operations for solid dosage formulations, (2) to make amorphous solid dispersion (ASD) granules without pre-preparation of amorphous solids of active pharmaceutical ingredients (API), and (3) to characterize the obtained SGR granules by comprehensive pharmaceutical analysis. Rebamipide (RBM), a biopharmaceutical classification system class IV drug, that has low solubility or permeability in the stomach, was selected as a model compound. Five kind of granules with different concentrations of polyvinylpyrrolidone/vinyl acetate copolymer (PVP-VA) were prepared using a one-step SGR process. All of the SGR granules could be produced in amorphous or ASD form and their thermodynamic stability was very high because of high glass transition temperatures (>178 °C). They were unstable in 20 °C/75%RH; however, their stability was improved according to the proportion of polymer. The carboxy group of RBM was ionized in the granules and interactions appeared between RBM and PVP-VA, with the formation of an ASD confirmed and the solubility was enhanced compared with bulk RBM crystals. The SGR methodology has the possibility of contributing to process development in the pharmaceutical industry.

Lipid Nanoemulsions of Rebamipide: Formulation, Characterization, and In Vivo Evaluation of Pharmacokinetic and Pharmacodynamic Effects

Rebamipide has low oral bioavailability (10%) due to its low solubility and permeability. Lipid nanoemulsions (LNEs) were prepared in order to improve its oral bioavailability. Rebamipide-loaded lipid nanoemulsions were formulated by hot homogenization and ultrasonication method. Olive oil and egg lecithin in various concentrations as emulsifier were used in the preparation of LNEs. The lipid nanoemulsions were evaluated for various parameters. The globule size, polydispersity index (PDI), and zeta potential (ZP) of the formulations ranged from 230.3 ± 3.88 to 279.8 ± 5.76 nm, 0.204 ± 0.008 to 0.246 ± 0.029, and - 27.7 ± 2.05 to - 31.0 ± 1.87 mV, respectively. Entrapment efficiency and assay values ranged from 99.90 ± 0.006 to 99.92 ± 0.002% and 99.3 ± 0.808 to 99.6 ± 0.360, respectively. Physical stability test results revealed that the optimized LNEs were stable for 2 months at both room (25°C) and refrigerated temperature (4°C). The optimized LNE showed 4.32-fold improvement in the oral bioavailability in comparison to a marketed tablet suspension. In vivo anti ulcer activity of rebamipide LNE was studied by testing the prophylactic effect in preventing the mucosal damage in stomach region. The mucosa of stomach in animals was damaged by per oral administration of 80% alcohol. Maximum prophylactic antiulcer activity was observed by per oral delivery of rebamipide as LNE. Our results indicated that LNEs were a promising approach for the oral delivery of rebamipide for systemic effects along with local effects in protecting gastric region, which gets damaged during peptic ulcers.

Rebamipide alleviates radiation-induced colitis through improvement of goblet cell differentiation in mice

BACKGROUND AND AIM

Radiation-induced colitis is a common clinical problem associated with radiotherapy and accidental exposure to ionizing radiation. Goblet cells play a pivotal role in the intestinal barrier against pathogenic bacteria. Rebamipide, an anti-gastric ulcer drug, has the effects to promote goblet cell proliferation. The aim of this study was to investigate whether radiation-induced colonic injury could be alleviated by rebamipide.

METHODS

This study orally administered rebamipide for 6 days to mice, which were subjected to 13 Gy abdominal irradiation, to evaluate the therapeutic effects of rebamipide against radiation-induced colitis. To confirm the effects of rebamipide on irradiated colonic epithelial cells, this study used the HT29 cell line.

RESULTS

Rebamipide clearly alleviated the acute radiation-induced colitis, as reflected by the histopathological data, and significantly increased the number of goblet cells. The drug also inhibited intestinal inflammation and protected from bacterial translocation during acute radiation-induced colitis. Furthermore, rebamipide significantly increased mucin 2 expression in both the irradiated mouse colon and human colonic epithelial cells. Additionally, rebamipide accelerated not only the recovery of defective tight junctions but also the differentiation of impaired goblet cells in an irradiated colonic epithelium, which indicates that rebamipide has beneficial effects on the colon.

CONCLUSIONS

Rebamipide is a therapeutic candidate for radiation-induced colitis, owing to its ability to inhibit inflammation and protect the colonic epithelial barrier.

Efficacy of rebamipide 2% ophthalmic solution in the treatment of dry eyes

AIM

The aim of this study is to evaluate the efficacy of 2% rebamipide ophthalmic solution on the tear functions and ocular surface status in patients with dry eyes.

MATERIALS AND METHODS

A prospective study was carried out on forty eyes of patients having signs and symptoms of dry eye. Two percent rebamipide ophthalmic solution was applied four times a day for a period of 4 weeks. Patients were evaluated on the basis of dry eye-related symptom score, tear film break-up time (TFBUT), tear meniscus height, fluorescein ocular surface staining score (FOSS), and the Schirmer's test at the end of 2, 4, 6, and 12 weeks and their values were compared with the baseline.

RESULTS

Significant improvement was noted in the mean dry eye-related symptom score, TBUT, and the FOSS values from the baseline at the end of 2, 4, 8, and 12 weeks. The values of tear meniscus height and Schirmer's test were improved at the end of 8 weeks but were not statistically significant.

CONCLUSION

Nearly 2% rebamipide ophthalmic solution provided relief in the symptoms of patients having dry eyes. It also prevented further ocular surface damage and aided in stabilizing the tear film.

Rebamipide suppresses TNF-α production and macrophage infiltration in the conjunctiva

PURPOSE

To evaluate the anti-inflammatory effect of rebamipide during corneal epithelial wound healing using a mouse wound repair model.

METHODS

A 2-mm circular disc of the central cornea was demarcated in the right eye of C57BL/6 mice and the epithelium removed. Rebamipide 2% eyedrop was instilled onto the wounded eye 5 times a day (n = 26). Phosphate-buffered saline (PBS) was used in the control group (n = 26). Corneal and conjunctival IL-1β and TNF-α levels were measured at 6 h and 24 h postinjury by ELISA. The wounded area was evaluated by fluorescein staining at 24 h postinjury. Macrophage infiltration was assessed immunohistochemically, and TNF-α secretion from macrophages was examined in vitro.

RESULTS

Conjunctival IL-1β and corneal IL-1β levels were not significantly different between PBS-treated and rebamipide-treated groups. However, conjunctival TNF-α level was significantly lower in the rebamipide-treated group compared with the PBS-treated group. Macrophage migration into the conjunctiva, but not into the cornea, was suppressed by rebamipide treatment. In addition, TNF-α secretion from cultured macrophages was suppressed by rebamipide in a concentration-dependent manner. Rebamipide treatment significantly accelerated corneal epithelial wound healing at 24 h postinjury.

CONCLUSIONS

In a mouse corneal epithelial wound model, rebamipide suppressed TNF-α secretion and macrophage infiltration in the conjunctiva, which might have contributed to accelerated corneal epithelial wound healing in the first 24 h following injury.

Implementation of Quality by Design for Formulation of Rebamipide Gastro-retentive Tablet

The purpose of the present study was to develop a rebamipide (RBM) gastro-retentive (GR) tablet by implementing quality by design (QbD). RBM GR tablets were prepared using a sublimation method. Quality target product profile (QTPP) and critical quality attributes (CQAs) of the RBM GR tablets were defined according to the preliminary studies. Factors affecting the CQAs were prioritized using failure mode and effects analysis (FMEA). Design space and optimum formulation were established through a mixture design. The validity of the design space was confirmed using runs within the area. The QTPP of the RBM GR tablets was the orally administered GR tablet containing 300 mg of RBM taken once daily. Based on the QTPP, dissolution rate, tablet friability, and floating property were chosen as CQAs. According to the risk assessment, the amount of sustained-release agent, sublimating material, and diluent showed high-risk priority number (RPN) values above 40. Based on the RPN, these factors were further investigated using mixture design methodology. Design space of formulations was depicted as an overlaid contour plot and the optimum formulation to satisfy the desired responses was obtained by determining the expected value of each response. The similarity factor (f2) of the release profile between predicted response and experimental response was 89.463, suggesting that two release profiles are similar. The validity of the design space was also confirmed. Consequently, we were able to develop the RBM GR tablets by implementing the QbD concept. These results provide useful information for development of tablet formulations using the QbD.

[Chronic gastritis: Instructions for use of medications]

The paper highlights the features of drug use in the legal aspect. It analyzes instructions for medical use of proton pump inhibitors (PPIs) and gastric protective agents. Taking into account the characteristics of indications registered in the instruction, the authors discuss the possibility of using various PPIs. The instruction for medical application is an official document approved by the Ministry of Health, the basis of which is the data of trials carried out by a manufacturer, and it should be a key or fundamental source for a physician in choosing a medication. The use of a drug with no indications given in the manual (the so-called 'off-label' use in foreign practice), is a clinical trial of a sort conducted by a physician individually, by taking upon himself/herself a legal liability. If arguments break out over the correct choice of this or that drug in treating the specific patient, the instruction containing the indications for use of specific medications to treat a specific disease is one of the proofs that the physician has correctly chosen the drug or a criterion for skilled medical care. The inclusion of chronic gastritis as a primary and only diagnosis into the primary documentation substantially limits the possibilities of using PPIs. When a PPI is indicated for therapy of erosive gastritis, a formal rationale is contained only in the instruction for use of Controloc. There are no registered indications for PPI use to treat chronic non-erosive gastritis; the gastric protective agent Rebagit is indicated.

Effect of topical rebamipide on goblet cells in the lid wiper of human conjunctiva

It has been demonstrated that topical administration of rebamipide, which is an antiulcer agent, increases the mucin level of the tear film and ameliorates ocular surface conditions such as lid wiper epitheliopathy. The aim of the present study was to analyze the changes in goblet cell number, cell proliferation, and epidermal growth factor receptor (EGFR) induced by topical rebamipide addition to the lid wiper of humans. A total of 30 eyelid tissue samples were obtained during involutional entropion surgeries, fixed in paraformaldehyde, embedded in paraffin and divided into two groups: Rebamipide or non-rebamipide. The tissues in the rebamipide group were obtained from patients who had a medical history of topical rebamipide use prior to surgery. The number of goblet cells was counted under light microscopy. A total of 22 eyelid tissue samples were further examined using immunohistochemistry with anti-Ki-67 and anti-EGFR antibodies to evaluate cell proliferation and EGFR expression, respectively. Histologically, the lid wiper and palpebral conjunctiva were clearly identified in the tissues. The number of goblet cells was significantly higher in the rebamipide group compared with the non-rebamipide group (P=0.0367). There was no significant difference in lid wiper cell proliferation between the rebamipide and non-rebamipide groups. Immunohistochemistry revealed that EGFR levels in the lid wiper epithelial cells were significantly higher in the rebamipide group compared with the non-rebamipide group (P=0.0237). These results suggest that topical rebamipide application increases the number of goblet cells in the lid wiper, which in turn upregulates the expression of EGFR. These findings may be clinically relevant and provide a therapeutic basis for the treatment of ocular disease such as dry eye and lid wiper epitheliopathy.

Comparison of Short-Term Effects of Diquafosol and Rebamipide on Mucin 5AC Level on the Rabbit Ocular Surface

PURPOSE

To investigate the short-term effects of 2 new secretagogue eye drops for dry eye, 3% diquafosol tetrasodium ophthalmic solution (diquafosol) and 2% rebamipide ophthalmic suspension (rebamipide), on the concentration of mucin 5AC (MUC5AC) in rabbit tear fluid and conjunctival goblet cells.

METHODS

One dose of artificial tears, diquafosol or rebamipide, was instilled into 8 eyes of Japanese white rabbits. MUC5AC concentration in the tear fluid was examined using the enzyme-linked immunosorbent assay 15 min after instillation and compared with 8 untreated controls. Impression cytology was performed to measure the number of periodic acid Schiff (PAS)-positive cells and the ratio of the PAS-positive area using image analysis software. Statistical comparison was performed using ANOVA with post hoc analysis with the Tukey's test.

RESULTS

After 15 min, only diquafosol significantly (P ≤ 0.01) increased the MUC5AC level in the tear fluid. Although no drug affected the number of PAS-positive cells, the ratio of the PAS-positive area decreased significantly (P ≤ 0.01) only in the diquafosol group.

CONCLUSIONS

These data indicated that more PAS-positive MUC5AC was released into the tear fluid from the goblet cells by diquafosol than by rebamipide. There is a difference in the induction pattern of MUC5AC into the tears from the goblet cells between these eye drops.

Rebamipide, an anti-ulcerative drug, inhibits induction of salivary dysfunction by benzodiazepines

OBJECTIVES

The purpose of this study was to determine whether rebamipide, an antistomach ulcer agent, ameliorated benzodiazepine-induced hyposalivation in rat parotid gland (PG) and submandibular gland (SMG).

METHODS

Saliva was collected from PG and SMG through a capillary cannula inserted into the parotid duct and sublingual papillae, respectively, every 15 min for 1 h after stimulation with pilocarpine dissolved in physiological saline and intraperitoneally administered at 1 mg kg^-1 . Diazepam (DZP) was administered intraperitoneally at a dose of 0.2 mg kg^-1 twice daily for 7 days. Rebamipide was administered at 10, 20, 30, or 100 mg kg^-1 concomitantly with DZP to determine its effect on hyposalivation. The effect of rebamipide on movement of intracellular calcium ([Ca²⁺ ]i) in isolated parotid acinar cells was analyzed using Fluo4, a fluorescent dye used to detect Ca²⁺ .

RESULTS

Repetitive administration of DZP decreased salivary secretion in PG and SMG. This inhibitory effect was weakened by administration of rebamipide. Prior administration of DZP (10^-6 M) significantly suppressed carbachol (10^-7 M)-induced increase in [Ca²⁺ ]i. This inhibitory effect was ameliorated by combined use with rebamipide (5 × 10^-4 M).

CONCLUSION

This findings suggest that rebamipide weakens the downregulatory effect of DZP on salivary secretion by preventing DZP-induced suppression of increase in [Ca²⁺ ]i.

Rebamipide Suppresses Monosodium Urate Crystal-Induced Interleukin-1β Production Through Regulation of Oxidative Stress and Caspase-1 in THP-1 Cells

This study investigated the effect of rebamipide on activation of the NLRP3 inflammasome and generation of reactive oxygen species (ROS) in monosodium urate (MSU) crystal-induced interleukin-1β (IL-1β) production. Human monocyte cell line THP-1 and human umbilical venous endothelial cells (HUVECs) were used to assess the inflammatory response to MSU crystals. NADP/NADPH activity assays were used as a marker of ROS generation. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were performed to evaluate levels of IL-1β, caspase-1, NLRP3, associated speck-like protein (ASC), nuclear factor-κB (NF-κB), p65, IκBα, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). Experimental pharmaceuticals included rebamipide, colchicine, dexamethasone, and ascorbic acid. In THP-1 cells, treatment with MSU crystals increased NADP/NADPH ratios and IL-1β expression, and both of these responses were potently inhibited by addition of rebamipide. Rebamipide also attenuated enhanced expression of caspase-1 gene by MSU crystals (p < 0.05). Western blotting demonstrated that MSU crystals stimulated caspase-1 but not NLRP3 and ASC activation. Similarly, MSU crystals activated the NF-κB pathway, which in turn was blocked by rebamipide. Stimulation of HUVECs with MSU crystals increased expression of VCAM-1 and ICAM-1, which were markedly inhibited by both rebamipide and dexamethasone. This study demonstrated that rebamipide inhibits IL-1β activation through suppression of ROS-mediated NF-κB signaling pathways and caspase-1 activation in MSU crystal-induced inflammation.

Determination of the adequate dosage of rebamipide, a gastric mucoprotective drug, to prevent low-dose aspirin-induced gastrointestinal mucosal injury

Small intestinal mucosal injury caused by low-dose aspirin is a common cause of obscure gastrointestinal bleeding. We aimed to investigate the protective effects and optimal dose of rebamipide for low-dose aspirin-induced gastrointestinal mucosal injury. In this prospective randomized trial, 45 healthy volunteers (aged 20–65 years) were included and divided into three groups. The groups received enteric-coated aspirin 100 mg (low-dose aspirin) plus omeprazole 10 mg (Group A: proton pump inhibitor group), low-dose aspirin plus rebamipide 300 mg (Group B: standard-dose group), or low-dose aspirin plus rebamipide 900 mg (Group C: high-dose group). Esophagogastroduodenoscopy and video capsule endoscopy were performed, and the fecal occult blood reaction and fecal calprotectin levels were measured before and two weeks after drug administration. Although the fecal calprotectin levels increased significantly in Group A, they did not increase in Groups B and C. The esophagogastroduodenoscopic and video capsule endoscopic findings and the fecal occult blood test findings did not differ significantly among the three groups. In conclusion, standard-dose rebamipide is sufficient for preventing mucosal injury of the small intestine induced by low-dose aspirin, indicating that high-dose rebamipide is not necessary.

Persistent corneal epithelial defect responding to rebamipide ophthalmic solution in a patient with diabetes

Objective

Rebamipide ophthalmic suspension was developed for the treatment of dry eyes and for other corneal diseases, promoting the secretion of both mucin in tear fluid and membrane-associated mucin, increasing the number of goblet cells, and restoring the barrier function of the corneal epithelium. We report a case of a persistent corneal epithelial defect in a patient with diabetes treated with topical application of rebamipide ophthalmic suspension.

Case presentation

A 73-year-old woman had a history of type 2 diabetes for 35 years and nonproliferative diabetic retinopathy for 23 years. She presented to our department with discharge and ophthalmalgia in the left eye. A corneal ulcer was detected, and culture of corneal scrapings was performed, with Staphylococcus aureus and Streptococcus canis being isolated. The infection was treated with levofloxacin eye drops and ofloxacin ophthalmic ointment based on the sensitivity profile of the isolate. However, a corneal epithelial defect persisted for approximately 2 months despite continuing treatment with 0.1% hyaluronic acid ophthalmic suspension and 0.3% ofloxacin eye ointment. Her hemoglobin A1c was 7.3%. The persistent corneal epithelial defect showed improvement at 2 weeks after treatment with rebamipide unit dose 2% ophthalmic suspension, and it did not recur even when vitrectomy was subsequently performed for vitreous hemorrhage due to progression of diabetic retinopathy.

Conclusion

This is the first report about efficacy of rebamipide unit dose 2% ophthalmic suspension for presenting persistent corneal epithelial defect in a patient with diabetes. In the present case, the suggested mechanisms are the following: improving the corneal barrier function, stabilization of mucin on the keratoconjunctival epithelium, and improving the wettability and stability of the tear film, which resulted in the promotion of healing of the corneal epithelial defect in a short time period.

Is the main lacrimal gland indispensable? Contributions of the corneal and conjunctival epithelia

The ocular surface system is responsible for ensuring that the precorneal tear film is sufficient in both quality and quantity to preserve optimal vision. Tear secretion is a complex, multifactorial process, and dysfunction of any component of the ocular surface system can result in tear film instability and hyperosmolarity with resultant dry eye disease. The tear film is primarily composed of lipids, aqueous, and mucins, with aqueous accounting for most of its thickness. The aqueous is produced by the main lacrimal gland, accessory lacrimal glands, and corneal and conjunctival epithelia. Although the main lacrimal gland has long been considered an indispensable source of the aqueous component of tears, there is evidence that adequate tear secretion can exist in the absence of the main lacrimal gland. We review and discuss the basics of tear secretion, the tear secretory capacity of the ocular surface, and emerging treatments for dry eye disease.

Rebamipide retards CCl4-induced hepatic fibrosis in rats: Possible role for PGE2

Prostaglandin E2 (PGE2) is a potent physiological suppressor of liver fibrosis. Because the anti-ulcer drug rebamipide can induce the formation of endogenous PGE2, this study investigated the potential effects of rebamipide on development of a hepatic fibrosis that was inducible by carbon tetrachloride (CCl4). Groups of Wistar rats received intraperitoneal (IP) injections of CCl4 (0.45 ml/kg [0.72 g CCl4/kg]) over the course of for 4 weeks. Sub-sets of CCl4-treated rats were also treated concurrently with rebamipide at 60 or 100 mg/kg. At 24 h after the final treatments, liver function and oxidative stress were indirectly assessed. The extent of hepatic fibrosis was evaluated using two fibrotic markers, hyaluronic acid (HA) and pro-collagen-III (Procol-III); isolated liver tissues underwent histology and were evaluated for interleukin (IL)-10 and PGE2 content. The results indicated that treatment with rebamipide significantly inhibited CCl4-induced increases in serum ALT and AST and also reduced oxidative stress induced by CCl4. Fibrotic marker assays revealed that either dose of rebamipide decreased the host levels of Procol-III and HA that had become elevated due to the CCl4. At the higher dose tested, rebamipide appeared to be able to permit the hosts to have a normal liver histology and to minimize any CCl4-induced collagen precipitation in the liver. Lastly, the use of rebamipide was seen to be associated with significant increases in liver levels of both PGE2 and the anti-inflammatory cytokine IL-10. Based on these findings, it is concluded that rebamipide can retard hepatic fibrosis induced by CCl4 and that this effect may, in part, be mediated by an induction of PGE2 and IL-10 in the liver itself.

[Small bowel injuries due to nonsteroidal anti-inflammatory drugs and antiplatelet therapy. Approaches to prevention and treatment]

Nonsteroidal anti-inflammatory drug (NSAID)-induced small bowel injuries (NSAID enteropathies) become clinically important. Videocapsule endoscopy shows that the small bowel is involved in NSAID-related gastrointestinal tract (GIT) injury in almost two-thirds of all cases. Due to a large number of patients who receive NSAIDs, combined antiplatelet therapy, or long use anticoagulants, GIT injury prevention becomes an actual problem. Treatment for NSAID enteropathy is different from that for NSAID gastropathy. In NSAID enteropathy, it is advisable to use drugs that are able to increase the production of prostaglandins and mucus, to restore intestinal epithelial permeability, and to exert anti-inflammatory and antioxidant effects. Rebamipide that produces many pleiotropic effects and also has cytoprotective properties may become the drug of choice for treating patients with NSAID enteropathy. In addition, rebamipide has no effects on various cytochrome P-450 enzyme systems, by reducing the risk of drug interactions.

Rebamipide suppresses mite-induced asthmatic responses in NC/Nga mice

Allergic asthma caused by continuous allergen exposure evokes allergen-specific Th2 responses and is characterized by chronic airway inflammation and hyperresponsiveness. A previous report showed that rebamipide improved asthmatic symptoms in an ovalbumin/trypsin mice model. However, it is still unclear how rebamipide exerts its effects in asthma. In this study, rebamipide improved the asthmatic responses induced by mite exposure in NC/Nga mice, revealing the mechanism of this therapeutic effect. Rebamipide suppressed the infiltration of eosinophils into the airways and lung as well as attenuating the production of reactive oxygen species in tissues. In addition to these anti-inflammatory effects, rebamipide inhibited the production of IL-33, a member of the IL-1 family that drives the subsequent production of Th2-associated cytokines. These observations identify the point where rebamipide exerts its suppressive action on asthma and suggest that rebamipide has therapeutic potential in preventing mite-induced asthma.

Rebamipide suppresses TNF-α mediated inflammation in vitro and attenuates the severity of dermatitis in mice

Rebamipide is a routine drug for the treatment of gastritis in a clinical setting. Recently, it has been shown to protect against various inflammatory diseases, and has provided a potential therapy for these diseases. However, whether rebamipide has a role in dermatitis remains to be elucidated. Here, we found that rebamipide alleviated the inflammatory reaction induced by tumor necrosis factor-α in RAW264.7, a stable macrophage cell line. Furthermore, rebamipide treatment repressed activation of nuclear factor-kappaB signaling, a well-established inflammatory signaling pathway. Moreover, an oxazolone-induced dermatitis mouse model was established to investigate the role of rebamipide in vivo. PBS control group exhibited typical skin inflammation, whereas treatment with rebamipide remarkably attenuated a dermatitis phenotype in this mouse model. The protective role of rebamipide in dermatitis in vivo was probably due to its inhibition of nuclear factor-kappaB signaling. Collectively, rebamipide may represent a promising molecular target for the prevention and treatment of inflammatory skin diseases.

Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.57-3.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy.

Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.57–3.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy.

Histological observation of goblet cells following topical rebamipide treatment of the human ocular surface: A case report

The topical administration of rebamipide (Mucosta®), an antiulcer agent, clinically increases the mucin level of tear film. The aim of this study was to report the histological changes of goblet cells following the topical administration of rebamipide to a patient with nevus of the lacrimal caruncle. A 62-year-old male exhibited a pigmented nodule located in the lacrimal caruncle in the left eye. An excisional biopsy and subsequent surgical resection were conducted at the caruncle, prior to and three months after topical rebamipide administration. Histologically, a biopsy specimen revealed a pigmented nevus beneath the caruncle epithelium containing a few goblet cells [4 cells/high power field (HPF)]. A few nevus cells were present at the surgical margin. By contrast, the secondary resected specimen obtained three months after the initiation of topical rebamipide treatment revealed the epithelium and nevus, where numerous goblet cells were present (28 cells/HPF), and mucin-like substances were markedly secreted from the goblet cells. Topical rebamipide markedly increased the number of goblet cells and stimulated the secretion of mucin-like substances in the caruncular tissue of a human patient. These results suggest that topical rebamipide is useful in patients following surgery and/or biopsy to support tissue repair of the ocular surface.

Effect of supplementation with rebamipide for Helicobacter pylori eradication therapy: a systematic review and meta-analysis

BACKGROUND AND AIM

Several studies have reported that the application of rebamipide during the eradication of Helicobacter pylori can improve the eradication rate. However, the efficacy and safety are controversial. The present study systematically evaluated whether rebamipide improves the eradication rate of H. pylori by conducting a meta-analysis based on randomized controlled trials (RCTs).

METHODS

Literature searches were conducted in the following database: PubMed, the Cochrane Library, and the Igaku-chuo-zasshi database in Japan. A meta-analysis of all RCTs comparing rebamipide supplementation with non-rebamipide-containing therapy was performed.

RESULTS

We identified six randomized trials (611 patients). Pooled H. pylori eradication rates by per-protocol analysis were 73.3% and 61.4% for patients with or without rebamipide, respectively. The odds ratio was 1.74 (95% confidence interval. 1.19-2.53).

CONCLUSIONS

Supplementation with rebamipide might be effective in increasing the H. pylori eradication rates of proton-pump inhibitor-amoxicillin dual therapy.

Effect of rebamipide on gastric bleeding and ulcerogenic responses induced by aspirin plus clopidogrel under stimulation of acid secretion in rats

BACKGROUND AND AIM

We examined the prophylactic effect of rebamipide on gastric bleeding induced by the perfusion of aspirin (acetylsalicylic acid [ASA]) plus clopidogrel under the stimulation of acid secretion in rats.

METHODS

Under urethane anesthesia, acid secretion was stimulated by the i.v. infusion of histamine (8 mg/kg/h), and the stomach was perfused with 25 mmol/L ASA at a rate of 0.4 mL/min. Gastric bleeding was evaluated as the concentration of hemoglobin in the perfusate. Clopidogrel (30 mg/kg) was given p.o. 24 h before the perfusion. Rebamipide (3-30 mg/kg) or other antiulcer drugs were given i.d. before the ASA perfusion.

RESULTS

Slight gastric bleeding or damage was observed with the perfusion of ASA under the stimulation of acid secretion, whereas these responses were significantly increased in the presence of clopidogrel. Both omeprazole and famotidine inhibited acid secretion and prevented these responses to ASA plus clopidogrel. Rebamipide had no effect on acid secretion, but dose-dependently prevented gastric bleeding in response to ASA plus clopidogrel, with the degree of inhibition being almost equivalent to that of the antisecretory drugs, and the same effects were obtained with the gastroprotective drugs, irsogladine and teprenone. These agents also reduced the severity of gastric lesions, although the effects were less than those of the antisecretory drugs.

CONCLUSIONS

These results suggest that the antiplatelet drug, clopidogrel, increases gastric bleeding induced by ASA under the stimulation of acid secretion, and the gastroprotective drug, rebamipide, is effective in preventing the gastric bleeding induced under such conditions, similar to antisecretory drugs.

Rebamipide protects small intestinal mucosal injuries caused by indomethacin by modulating intestinal microbiota and the gene expression in intestinal mucosa in a rat model

The effect of rebamipide, a mucosal protective drug, on small intestinal mucosal injury caused by indomethacin was examined using a rat model. Indomethacin administration (10 mg/kg, p.o.) induced intestinal mucosal injury was accompanied by an increase in the numbers of intestinal bacteria particularly Enterobacteriaceae in the jejunum and ileum. Rebamipide (30 and 100 mg/kg, p.o., given 5 times) was shown to inhibit the indomethacin-induced small intestinal mucosal injury and decreased the number of Enterococcaceae and Enterobacteriaceae in the jejunal mucosa to normal levels. It was also shown that the detection rate of segmented filamentous bacteria was increased by rebamipide. PCR array analysis of genes related to inflammation, oxidative stress and wound healing showed that indomethacin induced upregulation and downregulation of 14 and 3 genes, respectively in the rat jejunal mucosa by more than 5-fold compared to that of normal rats. Rebamipide suppressed the upregulated gene expression of TNFα and Duox2 in a dose-dependent manner. In conclusion, our study confirmed that disturbance of intestinal microbiota plays a crucial role in indomethacin-induced small intestinal mucosal injury, and suggests that rebamipide could be used as prophylaxis against non-steroidal anti-inflammatory drugs -induced gastrointestinal mucosal injury, by modulating microbiota and suppressing mucosal inflammation in the small intestine.

Evaluation of dacryocystorhinostomy using optical coherence tomography and rebamipide ophthalmic suspension

Purpose

To evaluate the surgical outcome of dacryocystorhinostomy (DCR) by measuring the tear meniscus, using optical coherence tomography and rebamipide ophthalmic suspension.

Methods

Patients with nasolacrimal obstruction and chronic dacryocystitis who were scheduled for an endonasal DCR underwent tear meniscus examinations before and 2 months after surgery. Vertical scans of the inferior menisci were performed before and at 1, 3, 5, 7, and 10 minutes after the instillation of rebamipide ophthalmic suspension. The tear menisci areas were measured with imaging software. Ten young adults without epiphora formed the control group.

Results

Anatomical success was achieved on 22 sides of 21 patients. The patients’ postoperative tear menisci were significantly smaller than the preoperative menisci at all points during the test, and the response to volume loading in the postoperative patients was corrected to nearly that of the young, healthy adults. Nevertheless, the postoperative meniscus area tended to be larger than that of the young adults at all points.

Conclusion

The reduced tear meniscus area after DCR reflected the success of the surgical procedure. However, incomplete recovery of the meniscus after the test might suggest a residual disorder of the lacrimal drainage system after DCR.