A cochleate formulation optimized by D-optimal mixture design enhances oral bioavailability of Revaprazan.

A cochleate formulation was developed to enhance the oral bioavailability of revaprazan (RVP). Dimyristoyl phosphatidylcholine (DMPC) liposome containing dicetyl phosphate (DCP) successfully formed a cochleate after treatment with CaCl2, whereas that containing sodium deoxycholate did not. Cochleate was optimised using a D-optimal mixture design with three independent variables-DMPC (X1, 70.58 mol%), cholesterol (X2, 22.54 mol%), and DCP (X3, 6.88 mol%)-and three response variables: encapsulation efficiency (Y1, 76.92%), released amount of free fatty acid at 2 h (Y2, 39.82%), and released amount of RVP at 6 h (Y3, 73.72%). The desirability function was 0.616, showing an excellent agreement between the predicted and experimental values. The cylindrical morphology of the optimised cochleate was visualised, and laurdan spectroscopy confirmed the dehydrated membrane interface, showing an increased generalised polarisation value (approximately 0.5) over small unilamellar vesicle of RVP (RVP-SUV; approximately 0.1). The optimised cochleate showed greater resistance to pancreatic enzyme than RVP-SUV. RVP was released in a controlled manner, achieving approximately 94% release in 12 h. Following oral administration in rats, the optimised cochleate improved the relative bioavailability of RVP by approximately 274%, 255%, and 172% compared to RVP suspension, a physical mixture of RVP and the cochleate, and RVP-SUV, respectively. Thus, the optimised cochleate formulation might be a good candidate for the practical development of RVP.

Sodium alginate-based smart gastro-retentive drug delivery system of revaprazan loaded SLNs; Formulation and characterization.

Revaprazan (REV), a novel reversible Proton Pump Inhibitor (PPI) used to treat peptic ulcers, faces challenges in therapeutic efficacy due to its poor dissolution properties and a short half-life. Solid lipid nanoparticles (SLNs) have emerged as a drug delivery system capable of enhancing dissolution and bioavailability of lipid soluble drugs. Here, we report on the development and optimization of a smart gastro-retentive raft system of REV-loaded SLNs (GRS/REV-SLNs) to enhance drug bioavailability and gastric retention. The optimized REV-SLNs had a particle size of 120 nm, a Polydispersity Index (PDI) of 0.313, a zeta potential of -20.7 mV, and efficient drug incorporation of 88 %. Transmission Electron Microscopy (TEM) affirmed the spherical morphology of these REV-SLNs, while Fourier Transform Infrared Spectroscopy (FTIR) revealed no chemical interactions among components. In-vitro assessment of the final GRS/REV-SLNs demonstrated sustained gelation and buoyancy for over 12 h, which would significantly enhance REV retention and its release within the stomach. Further assessments in rats confirmed successful gel transformation within the stomach, resulting in the improved bioavailability of REV. Thus, the development of GRS/REV-SLNs significantly improved the delivery and bioavailability of REV within the stomach, and offers a potentially improved method of treating peptic ulcers.

Enhanced dissolution and bioavailability of revaprazan using self-nanoemulsifying drug delivery system.

A self-nanoemulsifying drug delivery system (SNEDDS) was developed to enhance the dissolution and oral bioavailability (BA) of revaprazan (RVP). Various SNEDDSs containing 200 mg of RVP were formulated using Capmul MCM, Tween 80, and Brij L4, and they were characterized according to their size, polydispersity index, and dissolution behavior. Dissolution rates of all SNEDDS formulations significantly (p < 0.05) improved with the formation of nanoemulsion with monodispersity. Formulation D resulted in RVP dissolution exceeding 70% at 2 h. Compared to raw RVP, SNEDDS exhibited a 4.8- to 7.4-fold improved effective permeability coefficient (Peff) throughout the intestine in the in situ single pass intestinal permeability study and a 5.1-fold increased oral BA in the in vivo oral absorption assessment in rats. To evaluate the degree of lymphatic uptake, cycloheximide (CYC), a chylomicron flowing blocker, was pretreated prior to the experiment. This pretreatment barely affected the absorption of raw RVP; however, it greatly influenced the absorption of SNEDDS, resulting in an approximately 40% reduction in both the Peff value and oral BA representing lymphatic transport. Thus, we suggest that the SNEDDS formulation is a good candidate for improving oral absorption of RVP through enhanced lymphatic uptake.

Development of a Solid Supersaturable Micelle of Revaprazan for Improved Dissolution and Oral Bioavailability Using Box-Behnken Design.

PURPOSE: To enhance the oral bioavailability of revaprazan (RVP), a novel solid, supersaturable micelle (SSuM) was developed. METHODS: Surfactants and solid carriers were screened based on a solubility and a flowability test, respectively. Supersaturating agents, including Poloxamer 407 (P407), were screened. The SSuM was optimized using a Box-Behnken design with three independent variables, including Gelucire 44/14:Brij L4 (G44/BL4; X1) and the amounts of Florite PS-10 (FLO; X2) and Vivapur 105 (VP105; X3), and three response variables, ie, dissolution efficiency at 30 min (Y1), dissolution enhancing capacity (Y2), and Carr's index (Y3). The solid state property was evaluated, and a dissolution test was conducted. RVP, Revanex®, solid micelle (P407-free from the composition of SSuM), and SSuM were orally administrated to rats (RVP 20 mg equivalent/kg) for in vivo pharmacokinetic study. RESULTS: G44 and BL4 showed great solubility, with a critical micelle concentration range of 119.2-333.0 µg/mL. P407 had an excellent supersaturating effect. FLO and VP105 were selected as solid carriers, with a critical solidifying ratio (g/mL) of 0.30 and 0.91, respectively. With optimized values of X1 (-0.41), X2 (0.31), and X3 (-0.78), RVP (200 mg)-containing SSuM consisting of G44 (253.8 mg), BL4 (106.2 mg), FLO (99.3 mg), VP105 (199.8 mg), and P407 (40 mg) was developed, resulting in Y1 (40.3%), Y2 (0.008), and Y3 (12.3%). RVP existed in an amorphous state in the optimized SSuM, and the SSuM formed a nanosized dispersion in the aqueous phase, with approximately 71.7% dissolution at 2 h. The optimized SSuM improved the relative bioavailability of RVP in rats by approximately 478%, 276%, and 161% compared to raw RVP, Revanex®, and solid micelle, respectively. CONCLUSION: The optimized SSuM has great potential for the development of solidified formulations of poorly water-soluble drugs with improved oral absorption.

Revaprazan prevented indomethacin-induced intestinal damages by enhancing tight junction related mechanisms.

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed medications for alleviating pain and inflammation but may cause gastrointestinal tract damage. Proton pump inhibitors (PPI) prevent NSAID-induced gastric damage but may aggravate intestinal damage via dysbiosis and intestinal permeability alteration. Currently, there is growing interest regarding the influence of potassium competitive acid blockers (PCAB) on NSAID-induced enteropathy. Here, we investigated the relative changes in indomethacin-induced enteropathy by combining indomethacin with pantoprazole (as PPI) or revaprazan (as PCAB). We examined intestinal permeability-related molecular changes in in vitro Caco-2 cell models and in an in vivo indomethacin-induced enteropathy rat model. Indomethacin alone or in combination with pantoprazole significantly increased relative lucifer yellow dye flux and decreased relative trans-epithelial electrical resistance and tight junction protein (TJP) expression compare to normal cells. In contrast, indomethacin combined with revaprazan significantly preserved TJPs compare to indomethacin-treated cells. MLC phosphorylation, Rho activation, and ERK activation responsible for TJP were significantly increased by indomethacin alone or a combination of indomethacin and pantoprazole but not by a combination of indomethacin and revaprazan. Intestinal damage scores significantly increased with indomethacin and pantoprazole combination but not with indomethacin and revaprazan combination. Indomethacin and pantoprazole combination significantly activated Rho-GTPase, p-MLC, and p-ERK but significantly decreased TJP expression. However, indomethacin and revaprazan combination significantly preserved TJPs and inactivated Rho-GTPase, MLC, and ERK. Hence, revaprazan rather than PPIs should be co-administered with NSAIDs to mitigate NSAID-induced intestinal damage.

Identification of Three Antimicrobials Activating Serotonin Receptor 4 in Colon Cells.

The serotonin receptor 4b (5-HTR4b) is expressed throughout the gastrointestinal tract, and its agonists are used in the treatment of irritable bowel syndrome with constipation (IBS-C). Today, there are no rapid assays for the identification of 5-HTR4b agonists. Here, we developed a luciferase-based 5-HTR4b assay capable of assessing one compound per second with a 38-fold dynamic range and nM limit of detection for serotonin. We used the assay to screen more than 1000 natural products and anti-infection agents and identified five new 5-HTR4b ligands: hordenine, halofuginone, proflavine, ethacridine, and revaprazan. We demonstrate that hordenine (antibiofilm), halofuginone (antiparasitic), and revaprazan (gastric acid reducer) activate 5-HTR4b in human colon epithelial cells, leading to increased cell motility or wound healing. The 5-HTR4b assay can be used to screen larger pharmaceutical libraries to identify novel treatments for IBS-C. This work shows that antimicrobials interact not only with the gut microbiota, but also with the human host.

Revaprazan-loaded surface-modified solid dispersion: physicochemical characterization and in vivo evaluation.

The purpose of this research was to develop a novel revaprazan-loaded surface-modified solid dispersion (SMSD) with improved drug solubility and oral bioavailability. The impact of carriers on aqueous solubility of revaprazan was investigated. HPMC and Cremophor A25 were selected as an appropriate polymer and surfactant, respectively, due to their high drug solubility. Numerous SMSDs were prepared with various concentrations of carriers, using distilled water, and the drug solubility of each was assessed. Moreover, the physicochemical properties, dissolution and pharmacokinetics of selected SMSD in rats were assessed in comparison to revaprazan powder. Of the SMSDs assessed, the SMSD composed of revaprazan/HPMC/Cremophor A25 at the weight ratio of 1:0.28:1.12 had the most enhanced drug solubility (∼6000-fold). It was characterized by particles with a relatively rough surface, suggesting that the carriers were attached onto the surface of the unchanged crystalline revaprazan powder. It had a significantly higher dissolution rate, AUC and Cmax, and a faster Tmax value in comparison to revaprazan powder, with a 5.3-fold improvement in oral bioavailability of revaprazan. Therefore, from an environmental perspective, this SMSD system prepared with water, and without organic solvents, should be recommended as a revaprazan-loaded oral pharmaceutical alternative.

Novel revaprazan-loaded gelatin microsphere with enhanced drug solubility and oral bioavailability.

To develop a novel revaprazan-loaded gelatine microsphere with enhanced solubility and oral bioavailability, numerous gelatine microspheres were prepared using a spray-drying technique. The impact of gelatine amount on drug solubility in the gelatine microspheres was investigated. The physicochemical properties of the selected gelatine microsphere, such as shape, particle size and crystallinity, were evaluated. Moreover, its dissolution and pharmacokinetics in rats were assessed in comparison with revaprazan powder. Amongst the gelatine microspheres tested, the gelatine microsphere consisting of revaprazan and gelatine (1:2, w/w), which gave about 150-fold increased solubility, had the most enhanced drug solubility. It provided a spherical shape, amorphous drug and reduced particle size. Furthermore, it gave a higher dissolution rate and plasma concentration than did revaprazan powder. Particularly, it gave about 2.3-fold improved oral bioavailability in comparison with revaprazan powder. Therefore, this novel gelatine microsphere system is recommended as an oral pharmaceutical product of poorly water-soluble revaprazan.

Comparison of a revaprazan-loaded solid dispersion, solid SNEDDS and inclusion compound: Physicochemical characterisation and pharmacokinetics.

The aim of this research was to compare three strategies for enhancing the solubility of poorly water-soluble revaprazan hydrochloride: solid dispersion, solid SNEDDS and inclusion compound. The influence of polymers, surfactants and oils on the drug solubility was assessed, and via the chosen carriers, the three types of formulations were prepared utilising spray drying technique. Their physicochemical properties, solubility, dissolution and pharmacokinetics in rats were performed compared with revaprazan powder. Among the liquid SNEDDS formulations assessed, the compositions of revaprazan, peceol, Tween 80 and Labrasol (10:15:55:30, weight ratio) provided the smallest emulsion size. Moreover, this liquid SNEDDS and dextran were suspended/dissolved in distilled water, and spray-dried, producing an optimal revaprazan-loaded solid SNEDDS. The appropriate solid dispersion and inclusion compound were composed of revaprazan, hydroxypropylmethylcellulose and cremophor A25 (5:1.4:5.6) and drug and hydroxyl-ß-cyclodextrin (2.5:8.77), respectively. The crystalline drug was converted to an amorphous state in all formulations. In the solid dispersion, the drug was attached to the hydrophilic carrier. The solid SNEDDS and inclusion compound contained aggregate microspheres and separate microspheres, respectively. All formulations significantly increased the drug solubility, dissolution, plasma concentration and AUC compared with revaprazan powder. These properties were ranked in the order solid dispersion ≥ solid SNEDDS > inclusion compound. Particularly, the solid dispersion improved about 9500-fold drug solubility and 10-fold oral bioavailability. Thus, the improved properties were considerably dependent upon these techniques, although all of the techniques employed similar mechanisms. Among the strategies checked, the solid dispersion system would be recommended as an oral revaprazan-loaded pharmaceutical product.

Revaprazan, a novel acid pump antagonist, exerts anti-inflammatory action against Helicobacter pylori-induced COX-2 expression by inactivating Akt signaling.

Chronic gastric inflammation developing after Helicobacter pylori (H. pylori) infection is responsible for either dyspeptic symptom relevant to gastritis/peptic ulcer or gastric tumorigenesis, in which acid suppressants, especially proton pump inhibitors (PPIs), play role in relieving dyspepsia as well as the eradication regimen. Among several mediators engaged in propagating gastric inflammation after H. pylori infection, cyclooxygenase-2 (COX-2) might be the principal one, and several prescriptions have been made for decreasing the COX-2 levels. Multiple line of evidence are available for anti-inflammatory action of PPIs beyond acid suppression, but revaprazan, a novel acid pump antagonist launched in clinic, has also been suggested to exert significant anti-inflammatory actions as much as PPI. In the current study, we hypothesized that revaprazan could regulate H. pylori-driven COX-2 expression as one of its anti-inflammatory pharmacological actions. The changes of gastric COX-2 expression as well as responsible transcription factors were measured after H. pylori infection in the presence or absence of revaprazan. Infection of AGS cells with H. pylori induced significant up-regulation of COX-2 in time- and concentration-dependent manners, which was mediated by Akt phosphorylation. Revaprazan treatment significantly inhibited IkappaB-alpha degradation as well as Akt inactivation, resulting in attenuation of H. pylori-induced COX-2 expression. Additional rescuing action of revaprazan against H. pylori-induced cytotoxicity was noted. In conclusion, revaprazan imposed significant anti-inflammatory actions on H. pylori infection beyond acid suppression.

The Efficacy of Short-term Administration of Revaprazan on Gastroesophageal Reflux Symptoms: Comparison with Half Dose Esomeprazole, a Pilot Study

BACKGROUND/AIMS: Revaprazan, an acid pump antagonist, is a kind of gastric acid suppressant and is prescribed for the treatment of peptic ulcers and gastritis. However, the efficacy of revaprazan on gastroesophageal reflux symptoms has not been established. The aim of this study was to evaluate the short-term efficacy of revaprazan on gastroesophageal reflux symptoms. MATERIALS AND METHODS: Patients who complained of gastroesophageal reflux symptoms without any specific diseases except gastritis on esophagogastroduodenoscopy were included in this study. Patients were randomized to receive revaprazan 200 mg or esomeprazole 20 mg for 2 weeks. Symptoms were assessed by using the frequency score questionnaire before and after treatment. RESULTS: Fifteen patients received revaprazan and 19 patients received esomeprazole. The changes of the symptom frequency score before and after treatment were 7.0 in revaprazan group and 8.6 in esomeprazole group (P=0.778). CONCLUSIONS: Revaprazan is not inferior to esomeprazole in therapeutic efficacy for gastroesophageal reflux symptoms and is a safe and useful therapeutic agent to reduce the frequency of gastroesophageal reflux symptoms.

A matched case-control study of a novel Acid-pump antagonist and proton-pump inhibitor for the treatment of iatrogenic ulcers caused by endoscopic submucosal dissection.

BACKGROUND/AIMS: Revaprazan, a novel acid-pump antagonist, and proton-pump inhibitors (PPIs) have pH-independent effects on ulcer healing. The addition of a PPI promotes the cell restitution rate as well as vessel regeneration and maturation for ulcer repair. Revaprazan is known to protect the mucosa by increasing the prostaglandin concentration. METHODS: We reviewed the medical records of patients who underwent endoscopic submucosal dissection (ESD) for gastric neoplasia at Yeungnam University Hospital between January 2008 and May 2009. We conducted a matched case-control study to compare the healing rates effected by revaprazan and rabeprazole. RESULTS: Each group consisted of 30 patients. The baseline characteristics did not differ significantly between the two groups. Stage S1 disease was observed in 97% and 100% of patients after 8 weeks of treatment in the revaprazan and rabeprazole groups, respectively. In the revaprazan group, only one patient had stage H2 disease: a 54-year-old man with a 5.5-cm lesion after ESD of the ulcer, type IIa early gastric cancer, and adenocarcinoma. No serious adverse effects occurred during the treatment period in either group. CONCLUSIONS: The safety and efficacy profiles of revaprazan and rabeprazole are similar for the treatment of ESD-induced ulcers.

A Matched Case-Control Study of a Novel Acid-Pump Antagonist and Proton-Pump Inhibitor for the Treatment of Iatrogenic Ulcers Caused by Endoscopic Submucosal Dissection

BACKGROUND/AIMS: Revaprazan, a novel acid-pump antagonist, and proton-pump inhibitors (PPIs) have pH-independent effects on ulcer healing. The addition of a PPI promotes the cell restitution rate as well as vessel regeneration and maturation for ulcer repair. Revaprazan is known to protect the mucosa by increasing the prostaglandin concentration. METHODS: We reviewed the medical records of patients who underwent endoscopic submucosal dissection (ESD) for gastric neoplasia at Yeungnam University Hospital between January 2008 and May 2009. We conducted a matched case-control study to compare the healing rates effected by revaprazan and rabeprazole. RESULTS: Each group consisted of 30 patients. The baseline characteristics did not differ significantly between the two groups. Stage S1 disease was observed in 97% and 100% of patients after 8 weeks of treatment in the revaprazan and rabeprazole groups, respectively. In the revaprazan group, only one patient had stage H2 disease: a 54-year-old man with a 5.5-cm lesion after ESD of the ulcer, type IIa early gastric cancer, and adenocarcinoma. No serious adverse effects occurred during the treatment period in either group. CONCLUSIONS: The safety and efficacy profiles of revaprazan and rabeprazole are similar for the treatment of ESD-induced ulcers.

Phase III Clinical Trial of Revaprazan (Revanex(R)) for Gastric Ulcer / 대한소화기내시경학회지

BACKGROUND/AIMS: This randomized, double-blind, phase III, multicenter trial was carried out to compare the efficacy and safety of revaprazan, a novel acid pump antagonist, with that of omeprazole in patients with more than one of gastric ulcers. METHODS: Two hundred and ninety two subjects were randomized to 4~8 weeks of treatment with either revaprazan 200 mg or omeprazole 20 mg. The primary efficacy parameter was the cumulative healing rate determined by endoscopy after 4 and 8 weeks of treatment, and the secondary efficacy parameter was an improvement rate of pain. RESULTS: The intention-to-treat analysis revealed revaprazan and omeprazole to have similar cumulative healing rates (93.0% and 89.6%, respectively; p=0.3038). The per-protocol analysis revealed revaprazan and omeprazole to also have similar cumulative healing rates (99.1% and 100%, respectively; p= 0.3229). In both analyses, there were no significant differences in an improvement rate of pain between the two groups. Both drugs were well tolerated. CONCLUSIONS: Revaprazan has similar efficacy to omeprazole in the treatment of patients with gastric ulcer with a once a day application of revaprazan 200 mg or omeprazole 20 mg over a 4 to 8-week period. In terms of safety, revaprazan was well tolerated.

Phase III Clinical Trial of Revaprazan (Revanex(R)) for Gastritis / 대한소화기내시경학회지

BACKGROUND/AIMS: We performed a randomized, double-blind, phase III, multicenter trial to assess the comparative efficacy and safety of revaprazan, which is a novel acid pump antagonist in comparison with ranitidine for treating patients suffering with acute gastritis and acute aggravation of chronic gastritis. METHODS: Five hundred and twelve subjects were randomized to 2 weeks of treatment with either revaprazan 200 mg q.d. or ranitidine 150 mg b.i.d. The primary efficacy parameter was the estimated improvement rate according to endoscopy, and the secondary efficacy parameter was the improvement rate for the subjects' symptoms. RESULTS: The estimated improvement rates at 2 weeks (intention-to-treat analysis) were 79.9% with revaprazan and 60.5% with ranitidine; a significant difference was found between the two groups (p<0.0001). On the per-protocol analysis, the estimated improvement rates for revaprazan and ranitidine were 79.4% and 60.2%, respectively. There was a significant difference in the estimated improvement rates between the two groups (p<0.0001). On both analyses, there were no significant differences between the two groups for the improvement rates of the subjects' symptoms. Both drugs were well tolerated. CONCLUSIONS: The efficacy of revaprazan was higher than that of ranitidine for the estimated improvement rate according to endoscopy and also for the symptomatological improvement rate, and revaprazan was well tolerated by the subjects suffering with gastritis.

Revaprazan (Revanex(R)), a Novel Acid Pump Antagonist, for Duodenal Ulcer: Results of a Double-Blind, Randomized, Parallel, Multi-Center Phase III Clinical Trial / 대한소화기내시경학회지

BACKGROUND/AIMS: To assess the comparative efficacy and safety of revaprazan, a novel acid pump antagonist, versus omeprazole in patients with duodenal ulcer, we performed a randomized, double-blind, phase III, multicenter trial. METHODS: Two hundred and twenty eight patients were randomized to 4 weeks of treatment with either revaprazan 200 mg or omeprazole 20 mg once daily. Primary efficacy parameter was complete ulcer healing by endoscopy, and secondary parameter was the improvement in the severity of daytime and nighttime pain. RESULTS: Healing rates at 4 weeks (intention-to-treat analysis) were 91.7% with revaprazan 200 mg and 91.3% with omeprazole 20 mg; there were no significant differences between two groups (p=0.9228). In per-protocol analysis, healing rates of revaprazan 200 mg and omeprazole 20 mg were 94.4% and 92.3%, respectively. There was no significant difference in healing rate between two groups (p=0.5666). There was no significant difference between two groups in improvement rates of daytime and nighttime pain. Both drugs were well tolerated. CONCLUSIONS: Revaprazan 200 mg was equivalent to omeprazole 20 mg for both ulcer healing and symptom relief, and was well tolerated in patients with duodenal ulcer.