Capmul MCM/Solutol HS15-Based Microemulsion for Enhanced Oral Bioavailability of Rebamipide

[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.

Evaluation of Safety, Tolerability and Pharmacokinetic Characteristics of SA001 and Its Active Metabolite Rebamipide after Single and Multiple Oral Administration

Dry eye disease (DED) is one of the most common eye diseases caused by multiple factors. Rebamipide, which is currently used to treat peptic ulcer disease, was shown to enhance secretory function and modulate inflammation in animal disease models. Considering the pathophysiology of DED, SA001 was developed expecting enhanced systemic exposure of rebamipide. Clinical trials to evaluate the safety, tolerability and pharmacokinetic (PK) characteristics of SA001 and its active metabolite rebamipide were conducted. After oral administration of SA001, blood and urine samples were collected for PK analysis of SA001 and rebamipide. PK parameters were compared between SA001 and conventional rebamipide (Bamedin^®) and also between fasted and fed. Safety and tolerability were evaluated throughout the study based on adverse events (AEs), physical examinations, vital signs, 12-lead electrocardiography and clinical laboratory tests. SA001 was rapidly absorbed and quickly converted to rebamipide. The systemic exposure of rebamipide was dose-proportional after single and multiple doses. The plasma concentration of rebamipide after administration of SA001 was higher with a dose adjusted AUC_last and C_max 2.20 and 5.45 times higher in the 240 mg dose group and 4.73 and 11.94 times higher in the 600 mg dose group compared to conventional rebamipide. The favorable PK and tolerability profiles support further clinical development.

Bedaquiline fumarate microemulsion: formulation optimization, rheological characterization and in vitro studies

Aim: Bedaquiline fumarate (BQF), an antitubercular drug, shows limited bioavailability due to solubility-limited intestinal absorption. In this research, the authors formulated a BQF-loaded microemulsion to improve BQF's oral bioavailability. Methods: Microemulsion was prepared by a spontaneous emulsification method and evaluated for thermodynamic stability, size, dispersibility, transmittance, rheology, microrheology, drug release, cytotoxicity and cellular uptake. Results: Microemulsion showed an average globule size of 26.50 ± 6.29 nm with spherical geometry and revealed gel-sol-gel behavior in microrheological studies. Cytotoxicity and cell uptake studies in Caco-2 cells showed that BQF microemulsion was cytocompatible at the highest concentration of 500 μg/ml with significantly higher cellular uptake than control. Conclusion: The present study indicates that BQF microemulsion could be explored further for effective treatment of multidrug-resistant tuberculosis.

Fundamental Aspects of Lipid-Based Excipients in Lipid-Based Product Development

Poor aqueous solubility of drugs is still a foremost challenge in pharmaceutical product development. The use of lipids in designing formulations provides an opportunity to enhance the aqueous solubility and consequently bioavailability of drugs. Pre-dissolution of drugs in lipids, surfactants, or mixtures of lipid excipients and surfactants eliminate the dissolution/dissolving step, which is likely to be the rate-limiting factor for oral absorption of poorly water-soluble drugs. In this review, we exhaustively summarize the lipids excipients in relation to their classification, absorption mechanisms, and lipid-based product development. Methodologies utilized for the preparation of solid and semi-solid lipid formulations, applications, phase behaviour, and regulatory perspective of lipid excipients are discussed.

Crotamiton-loaded tea tree oil containing phospholipid-based microemulsion hydrogel for scabies treatment: in vitro, in vivo evaluation, and dermatokinetic studies

Crotamiton (CRT) is a commonly approved drug prescribed for the scabies treatment in many countries across the globe. However, poor aqueous solubility and low bioavailability, and side effects restrict its use. To avoid such issues, an appropriate carrier system is necessary which can address the aforementioned challenges for attaining enhanced biopharmaceutical attributes. The current study intends to provide a detailed account on the development and evaluation of CRT-loaded microemulsion (ME) hydrogel formulation containing tea tree oil (TTO) for improved drug delivery for scabies treatment in a safe and effective manner. Pseudo-ternary phase diagrams were constructed with TTO as the oily phase, and Cremophor^®EL was used as the surfactant in a mass ratio 2:1 with co-surfactants (mixture of phospholipid 90G and Transcutol^®P), and aqueous solution as the external phase. The optimized drug-loaded ME formulation was evaluated for skin penetration, retention, compliance, and dermatokinetics. The nonirritant behavior of the formulation was revealed by skin histopathology, which showed no changes in normal skin histology. In comparison to the conventional product, dermatokinetic experiments revealed that CRT has greater penetration and distribution in the epidermis of the mice skin. The findings imply that the proposed lipid-based ME hydrogel can aid in the resolution of CRT issues by providing a better and safer delivery option to epidermis and deeper epidermis in substantial quantities.

Development of rebamipide-loaded spray-dried microsphere using distilled water and meglumine: physicochemical characterization and pharmacokinetics in rats

In this study, a novel rebamipide-loaded spray-dried microsphere (RSM) with enhanced drug solubility and oral bioavailability has been developed utilizing meglumine, an alkalizing agent. The influence of carriers on the drug solubility alone, and the solubility and dissolution of the drug in the RSM was investigated. Among the alkalizing agents and hydrophilic polymers tested, meglumine and polyvinyl alcohol (PVA) showed the highest drug solubility and dissolution rate, respectively. Many RSMs were manufactured with various amounts of meglumine and PVA using distilled water, and their drug solubility and dissolution were determined. The physicochemical properties, dissolution and pharmacokinetics of the chosen RSM in rats were assessed compared to the rebamipide powder and commercial tablet. Among the RSMs tested, the one composed of rebamipide, meglumine and PVA at a weight ratio of 3:1.75:6 showed the highest drug solubility and dissolution. This RSM with a smooth spherical form significantly decreased the particle size and modified the amorphous rebamipide. Furthermore, the drug solubility, dissolution, plasma concentrations, AUC and C_max values of RSM were significantly higher than those of drug powder and commercial tablet. Thus, this RSN system developed with distilled water and meglumine is recommended as an oral water-soluble rebamipide-loaded pharmaceutical product.

Formulation of a Self-Nanoemulsifying Drug Delivery System of Buckwheat Flavonoids and Evaluation of Its Antimicrobial Activity

This study was aimed at constructing a self-nanoemulsifying drug delivery system of buckwheat flavonoids and evaluating its antimicrobial activity. The construction of the nanoemulsion followed a pseudo-ternary phase diagram, and its particle properties (particle size, zeta potential, and surface morphology) and physicochemical parameters (turbidity, surface tension, pH value, conductivity, encapsulation efficiency, and stability) were evaluated. The antimicrobial potential of buckwheat flavonoids nanoemulsion was determined against Staphylococcus aureus, Escherichia coli, and Candida albicans and compared to the buckwheat flavonoids suspension. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) exhibited that the antimicrobial activity of the nanoemulsions and suspension increased while enhancing the drug concentration, and the antimicrobial activity of nanoemulsion was significantly higher than that of the suspension against those three bacteria. Agar disc diffusion test demonstrated that the inhibition zone diameter of the suspension was about 50% of the nanoemulsion against three bacteria. The time killing assay indicated that the IC₅₀ of the nanoemulsion was significantly lower than that of the suspension. These results indicate that nanoemulsion is a promising drug delivery system, which can improve the antimicrobial activity of buckwheat flavonoids.

Pharmacological and clinical feature of rebamipide: new therapeutic targets

Rebamipide is a cytoprotector developed in Japan where it has been successfully used for the treatment of stomach diseases for 30 years. Initially discovered effects of the drug included the induction of prostaglandins and the elimination of free oxygen radicals. Recent studies discovered new therapeutic targets of the drug, its new forms that made possible using rebamipid for the treatment of such diseases as NSAID enteropathy, ulcerative colitis, radiation colitis, pouchitis, enteropathy with impaired membrane digestion. It is used in endoscopy, ophthalmology, chemotherapy, rheumatology. The aim of this review is to present current information about the pharmacological and clinical feature of rebamipide and to study its therapeutic potential.

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.

Microemulsion-based hydrogels for enhancing epidermal/dermal deposition of topically administered 20(S)-protopanaxadiol: in vitro and in vivo evaluation studies

BACKGROUND

20(S)-Protopanaxadiol (20S-PPD) is a fully deglycosylated ginsenoside metabolite and has potent dermal antiaging activity. However, because of its low aqueous solubility and large molecular size, a suitable formulation strategy is required to improve its solubility and skin permeability, thereby enhancing its skin deposition. Thus, we optimized microemulsion (ME)-based hydrogel (MEH) formulations for the topical delivery of 20S-PPD.

METHODS

MEs and MEHs were formulated and evaluated for their particle size distribution, morphology, drug loading capacity, and stability. Then, the deposition profiles of the selected 20S-PPD-loaded MEH formulation were studied using a hairless mouse skin model and Strat-M membrane as an artificial skin model.

RESULTS

A Carbopol-based MEH system of 20S-PPD was successfully prepared with a mean droplet size of 110 nm and narrow size distribution. The formulation was stable for 56 d, and its viscosity was high enough for its topical application. It significantly enhanced the in vitro and in vivo skin deposition of 20S-PPD with no influence on its systemic absorption in hairless mice. Notably, it was found that the Strat-M membrane provided skin deposition data well correlated to those obtained from the in vitro and in vivo mouse skin studies on 20S-PPD (correlation coefficient r 2 = 0.929‒0.947).

CONCLUSION

The MEH formulation developed in this study could serve as an effective topical delivery system for poorly soluble ginsenosides and their deglycosylated metabolites, including 20S-PPD.

Self-nanoemulsifying drug delivery system of bruceine D: a new approach for anti-ulcerative colitis

Background

Bruceine D (BD) is a major bioactive component isolated from the traditional Chinese medicinal plant Brucea javanica which has been widely utilized to treat dysentery (also known as ulcerative colitis [UC]).

Methods

To improve the water solubility and absolute bioavailability of BD, we developed a self-nanoemulsifying drug delivery system (SNEDDS) composing of MCT (oil), Solutol HS-15 (surfactant), propylene glycol (co-surfactant) and BD. The physicochemical properties and pharmacokinetics of BD-SNEDDS were characterized, and its anti-UC activity and potential mechanism were evaluated in TNBS-induced UC rat model.

Results

The prepared nanoemulsion has multiple beneficial aspects including small mean droplet size, low polydispersity index (PDI), high zeta potential (ZP) and excellent stability. Transmission electron microscopy showed that nanoemulsion droplets contained uniform shape and size of globules. Pharmacokinetic studies demonstrated that BD-SNEDDS exhibited enhanced pharmacokinetic parameters as compared with BD-suspension. Moreover, BD-SNEDDS significantly restored the colon length and body weight, reduced disease activity index (DAI) and colon pathology, decreased histological scores, diminished oxidative stress, and suppressed TLR4, MyD88, TRAF6, NF-κB p65 protein expressions in TNBS-induced UC rat model.

Conclusion

These results demonstrated that BD-SNEDDS exhibited highly improved oral bioavailability and advanced anti-UC efficacy. In conclusion, our current results provided a foundation for further research of BD-SNEDDS as a potential complementary therapeutic agent for UC treatment.