Self-Microemulsifying Drug Delivery Systems: An Attractive Strategy for Enhanced Therapeutic Profile

Lipid-Based Self-Microemulsion of Niclosamide Achieved Enhanced Oral Delivery and Anti-Tumor Efficacy in Orthotopic Patient-Derived Xenograft of Hepatocellular Carcinoma in Mice

Introduction

We previously identified niclosamide as a promising repurposed drug candidate for hepatocellular carcinoma (HCC) treatment. However, it is poorly water soluble, limiting its tissue bioavailability and clinical application. To overcome these challenges, we developed an orally bioavailable self-microemulsifying drug delivery system encapsulating niclosamide (Nic-SMEDDS).

Methods

Nic-SMEDDS was synthesized and characterized for its physicochemical properties, in vivo pharmacokinetics and absorption mechanisms, and in vivo therapeutic efficacy in an orthotopic patient-derived xenograft (PDX)-HCC mouse model. Niclosamide ethanolamine salt (NEN), with superior water solubility, was used as a positive control.

Results

Nic-SMEDDS (5.6% drug load) displayed favorable physicochemical properties and drug release profiles in vitro. In vivo, Nic-SMEDDS displayed prolonged retention time and plasma release profile compared to niclosamide or NEN. Oral administration of Nic-SMEDDS to non-tumor bearing mice improved niclosamide bioavailability and Cmax by 4.1- and 1.8-fold, respectively, compared to oral niclosamide. Cycloheximide pre-treatment blocked niclosamide absorption from orally administered Nic-SMEDDS, suggesting that its absorption was facilitated through the chylomicron pathway. Nic-SMEDDS (100 mg/kg, bid) showed greater anti-tumor efficacy compared to NEN (200 mg/kg, qd); this correlated with higher levels (p < 0.01) of niclosamide, increased caspase-3, and decreased Ki-67 in the harvested PDX tissues when Nic-SMEDDS was given. Biochemical analysis at the treatment end-point indicated that Nic-SMEDDS elevated lipid levels in treated mice.

Conclusion

We successfully developed an orally bioavailable formulation of niclosamide, which significantly enhanced oral bioavailability and anti-tumor efficacy in an HCC PDX mouse model. Our data support its clinical translation for the treatment of solid tumors.

Simplex Lattice Design and Machine Learning Methods for the Optimization of Novel Microemulsion Systems to Enhance p-Coumaric Acid Oral Bioavailability: In Vitro and In Vivo Studies

Novel p-coumaric acid microemulsion systems were developed to circumvent its absorption and bioavailability challenges. Simplex-lattice mixture design and machine learning methods were employed for optimization. Two optimized formulations were characterized using in vitro re-dispersibility and cytotoxicity on various tumor cell lines (MCF-7, CaCO2, and HepG2). The in vivo bioavailability profiles of the drug loaded in the two microemulsion systems and in the suspension form were compared. The optimized microemulsions composed of Labrafil M1944 CS (5.67%)/Tween 80 (38.71%)/Labrasol (38.71%)/water (16.92%) and Capryol 90 (0.50%)/Transcutol P (26.67%)/Tween 80 (26.67%)/Labrasol (26.67%)/water (19.50%), respectively. They revealed uniform and stable p-coumaric acid-loaded microemulsion systems with a droplet size diameter of about 10 nm. The loaded microemulsion formulations enhanced the drug re-dispersibility in contrast to the drug suspension which exhibited 5 min lag time. The loaded formulae were significantly more cytotoxic on all cell lines by 11.98-16.56 folds on MCF-7 and CaCo2 cells and 47.82-98.79 folds on HepG2 cells higher than the pure drug. The optimized microemulsions were 1.5-1.8 times more bioavailable than the drug suspension. The developed p-coumaric acid microemulsion systems could be considered a successful remedy for diverse types of cancer.

Preparation and Evaluation of a Self-Emulsifying Drug Delivery System for Improving the Solubility and Permeability of Ticagrelor

Ticagrelor (TCG) is a BCS class IV antiplatelet drug used to prevent platelet aggregation in patients with acute coronary syndrome, having poor solubility and permeability. The goal of this study was to develop a self-nanoemulsifying drug delivery system (SNEDDS) of TCG to improve its solubility and permeability. The excipients were selected based on the maximum solubility of TCG and observed by UV spectrophotometer. Different combinations of oil, surfactant, and co-surfactant (1:1, 2:1, and 3:1) were used to prepare TCG-SNEDDS formulations, and pseudo-ternary phase diagrams were plotted. The nanoemulsion region was observed. Clove oil (10-20%), Tween-80 (45-70%), and PEG-400 (20-45%) were used as an oil, surfactant, and co-surfactant, respectively. The selected formulations (F1, F2, F3, F4, F5, and F6) were analyzed for ζ potential, polydispersity index (PDI), ζ size, self-emulsification test, cloud point determination, thermodynamic studies, entrapment efficiency, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), in vitro dissolution, ex vivo permeation, and pharmacodynamic study. The TCG-SNEDDS formulations exhibited ζ potential from -9.92 to -6.23 mV, a ζ average of 11.85-260.4 nm, and good PDI. The in vitro drug release in phosphate buffer pH 6.8 from selected TCG-SNEDDS F4 was about 98.45%, and F6 was about 97.86%, displaying improved dissolution of TCG in 0.1 N HCl and phosphate buffer pH 6.8, in comparison to 28.05% of pure TCG suspension after 12 h. While the in vitro drug release in 0.1 N HCl from F4 was about 62.03%, F6 was about 73.57%, which is higher than 10.35% of the pure TCG suspension. In ex vivo permeability studies, F4 also exhibited an improved apparent permeability of 2.7 × 10-6versus 0.6708 × 10-6 cm2/s of pure drug suspension. The pharmacodynamic study in rabbits demonstrated enhanced antiplatelet activity from TCG-SNEDDS F4 compared to that from pure TCG suspension. These outcomes imply that the TCG-SNEDDS may serve as an effective means of enhancing TCG's antiplatelet activity by improving the solubility and permeability of TCG.

Croton cajucara: Patents and Nanotechnological Advances

Croton cajucara Benth showed several pharmacological properties such as: antiinflammatory, antinociceptive hypoglycemic, lipid-lowering, antiulcer, antiestrogenic, antitumor, antigenotoxic, antimutagenic, and cardiovascular. The 19-nor-clerodane diterpene transdehydrocrotonin (t-DCTN or DCTN) is the major bioactive constituent extracted from the bark of this Croton. Patents for Croton cajucara Benth in the period 2015 to 2022 comprises 14 published documents. Among them 4 patents are colloidal systems (SM/SNEDDS) loading t-DCTN for pharmacological applications. Patent registrations highlighted the huge promising biotechnological potential of Croton cajucara Benth especially in the phytotherapy field, and the correlation with its bioactive constituents of which t-DCTN showed the foremost results, so this herbal could become an alternative in the treatment of COVID-19. However, investigation of more recently published patents for clerodane diterpenes with similar chemical structure of t-DCTN, who previously showed antiviral property must be carried out and should be searched on several patent data bases.

Exploring LIPIDs for their potential to improves bioavailability of lipophilic drugs candidates: A review

This review aims to provide a thorough examination of the benefits, challenges, and advancements in utilizing lipids for more effective drug delivery, ultimately contributing to the development of innovative approaches in pharmaceutical science. Lipophilic drugs, characterized by low aqueous solubility, present a formidable challenge in achieving effective delivery and absorption within the human body. To address this issue, one promising approach involves harnessing the potential of lipids. Lipids, in their diverse forms, serve as carriers, leveraging their unique capacity to enhance solubility, stability, and absorption of these challenging drugs. By facilitating improved intestinal solubility and selective lymphatic absorption of porously permeable drugs, lipids offer an array of possibilities for drug delivery. This versatile characteristic not only bolsters the pharmacological efficacy of drugs with low bioavailability but also contributes to enhanced therapeutic performance, ultimately reducing the required dose size and associated costs. This comprehensive review delves into the strategic formulation approaches that employ lipids as carriers to ameliorate drug solubility and bioavailability. Emphasis is placed on the critical considerations of lipid type, composition, and processing techniques when designing lipid-based formulations. This review meticulously examines the multifaceted challenges that come hand in hand with lipid-based formulations for lipophilic drugs, offering an insightful perspective on future trends. Regulatory considerations and the broad spectrum of potential applications are also thoughtfully discussed. In summary, this review presents a valuable repository of insights into the effective utilization of lipids as carriers, all aimed at elevating the bioavailability of lipophilic drugs.

Oral Drug Delivery Systems Applied to Launched Products: Value for the Patients and Industrial Considerations

Drug delivery systems (DDS) control the amount, rate, and site of administration of drug substances in the body as well as their release and ADME (absorption, distribution, metabolism, excretion). Among the various types of DDS, amount-controlled DDS for solubilization and absorption increase the bioavailability. Time- and amount-controlled DDS are controlled release formulations classified as (1) membrane-type, (2) matrix-type, (3) osmotic-type, and (4) ion-exchange type. Timed-release formulations also control the time and amount of release and the absorption of drugs. Site- and amount-controlled DDS are characterized by colonic delivery and intestinal lymph-targeting to improve release and ADME of drug substances. Finally, site-, time-, and amount-controlled DDS are gastroretentive formulations and local delivery in the oral cavity to improve site retention, release, and ADME of drugs. DDS can enhance efficacy, reduce adverse effects, and optimize the dosing frequency of various drug products to increase patient value. This review focuses on patient value and industrial considerations of launched oral DDS. We provide a technological overview of candidate and marketed DDS, as well as the pros/cons of the technologies for industrialization with consideration to excipients, manufacturing, and storage stability. Moreover, to demonstrate the usefulness of the technology and support the selection and development of the best technologies for patients, we also describe patient value from clinical studies and analyses, particularly with regard to increased new medical options, higher efficacy, reduced adverse effects, reduced number of doses and clinic visits, easier administration, higher quality of life, greater adherence, and satisfaction.

Celecoxib Oral Solution and the Benefits of Self-Microemulsifying Drug Delivery Systems (SMEDDS) Technology: A Narrative Review

INTRODUCTION

The oral route of drug delivery is the most widespread and preferred route of administration, but it has several limitations, including variable pharmacokinetics (PK), reduced dissolution and absorption, and gastrointestinal irritation. Further, many compounds have low aqueous solubility, which also limits intestinal absorption.

METHODS

For this narrative review, we conducted a literature search of PubMed until August 2022, focusing on emulsions, microemulsions, nanoemulsions, and self-emulsifying drug delivery systems.

RESULTS

The self-microemulsifying drug delivery system (SMEDDS) overcomes these limitations of hydrophobic compounds to enhance their bioavailability. A SMEDDS formulation is a clear, thermodynamically stable, oil-in-water emulsion of lipid, solubilized drug, and two surfactants, which spontaneously forms droplets < 100 nm in diameter. These components help deliver presolubilized drugs to the gastrointestinal tract, while protecting them from degradation in gastric acid or first-pass hepatic metabolism. SMEDDS formulations have improved oral drug delivery in the treatment of cancer (paclitaxel), viral infections (ritonavir), and migraine headache (ibuprofen and celecoxib oral solution). The American Headache Society recently updated their consensus statement for the acute treatment of migraine and included a selective cyclo-oxygenase-2 selective inhibitor formulated in SMEDDS, celecoxib oral solution. This SMEDDS formulation showed pronounced improvement in bioavailability compared with celecoxib capsules, allowing for a low dose of celecoxib in the oral solution to provide safe and effective acute migraine treatment. Here, we will focus on SMEDDS formulations, what differentiates them from other analogous emulsions as vehicles for poorly soluble drugs, and their clinical application in the acute treatment of migraine.

CONCLUSIONS

Oral drugs reformulated in SMEDDS have shown accelerated times to peak plasma drug concentrations and increased maximum plasma concentrations, compared with capsules, tablets, or suspensions. SMEDDS technology increases both drug absorption and bioavailability of lipophilic drugs, compared with other formulations. Clinically, this allows the use of lower doses with improved PK profiles without compromising efficacy, as shown with celecoxib oral solution for the acute treatment of migraine.

Oral insulin delivery: Barriers, strategies, and formulation approaches: A comprehensive review

Diabetes Mellitus is characterized by a hyperglycemic condition which can either be caused by the destruction of the beta cells or by the resistance developed against insulin in the cells. Insulin is a peptide hormone that regulates the metabolism of carbohydrates, proteins, and fats. Type 1 Diabetes Mellitus needs the use of Insulin for efficient management. However invasive methods of administration may lead to reduced adherence by the patients. Hence there is a need for a non-invasive method of administration. Oral Insulin has several merits over the conventional method including patient compliance, and reduced cost, and it also mimics endogenous insulin and hence reaches the liver by the portal vein at a higher concentration and thereby showing improved efficiency. However oral Insulin must pass through several barriers in the gastrointestinal tract. Some strategies that could be utilized to bypass these barriers include the use of permeation enhancers, absorption enhancers, use of suitable polymers, use of suitable carriers, and other agents. Several formulation types have been explored for the oral delivery of Insulin like hydrogels, capsules, tablets, and patches which have been described briefly by the article. A lot of attempts have been made for developing oral insulin delivery however none of them have been commercialized due to numerous shortcomings. Currently, there are several formulations from the companies that are still in the clinical phase, the success or failure of some is yet to be seen in the future.

Application of Design of Experiments in the Development of Self-Microemulsifying Drug Delivery Systems

Oral delivery has become the route of choice among all other types of drug administrations. However, typical chronic disease drugs are often poorly water-soluble, have low dissolution rates, and undergo first-pass metabolism, ultimately leading to low bioavailability and lack of efficacy. The lipid-based formulation offers tremendous benefits of using versatile excipients and has great compatibility with all types of dosage forms. Self-microemulsifying drug delivery system (SMEDDS) promotes drug self-emulsification in a combination of oil, surfactant, and co-surfactant, thereby facilitating better drug solubility and absorption. The feasible preparation of SMEDDS creates a promising strategy to improve the drawbacks of lipophilic drugs administered orally. Selecting a decent mixing among these components is, therefore, of importance for successful SMEDDS. Quality by Design (QbD) brings a systematic approach to drug development, and it offers promise to significantly improve the manufacturing quality performance of SMEDDS. Furthermore, it could be benefited efficiently by conducting pre-formulation studies integrated with the statistical design of experiment (DoE). In this review, we highlight the recent findings for the development of microemulsions and SMEDDS by using DoE methods to optimize the formulations for drugs in different excipients with controllable ratios. A brief overview of DoE concepts is discussed, along with its technical benefits in improving SMEDDS formulations.

Improved oral bioavailability of poorly water-soluble vorinostat by self-microemulsifying drug delivery system

Background

Vorinostat is a histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) with anticancer properties. However, it is plagued by low water solubility, low permeability (BCS class IV drug), and suboptimal pharmacokinetics. The purpose of the present study was to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the oral bioavailability of vorinostat. Capryol 90, labrasol, and polyethylene glycol (PEG 400) were selected as oil phase, surfactant, and co-surfactant, respectively. The vorinostat self-microemulsifying drug delivery systems were tested for self-microemulsifying time, phase separation, effect of pH, droplet size, zeta potential, dilution study, Fourier-transform infrared (FT-IR) spectroscopy analysis, and field emission scanning electron microscopy (FESEM). A rat model in vivo pharmacokinetic study was conducted for the optimized formulation against vorinostat pure drug powder.

Results

The results from the characterization studies showed that the optimized formulation (F7) self-microemulsification time was 1.4 ± 0.05 min and no precipitation or phase separation was observed. The mean droplet size, polydispersity index (PDI), and zeta potential of the optimized formulation (F7) were found to be 272.9 ± 82.7 nm, 0.415, and − 57.2 mV, respectively. The pharmacokinetic parameters of the optimized formulation (F7) showed a 1.6-fold increase in maximum concentration (Cmax) and a 3.6-fold increase in area under the curve (AUC(0−∞)), in comparison with pure drug in suspension.

Conclusions

The findings suggest that SMEDDS formulation could be an effective method for increasing the oral bioavailability of vorinostat, which is poorly water soluble.

Dihydroartemesinin and Curcumin Based Self-Microemulsifying Drug Delivery System for Antimalarial Activity

Malaria is a significant global problem which still persists despite the development of various effective antimalarial drugs. It is challenging to treat this disease due to the parasite's complex life cycle and high recrudensce of antimalarial drugs. A new self-micro emulsifying drug delivery system has been developed to improve the solubility of dihydroartemisinin and curcumin. The prepared formulation contained Dihydroartemesinin, curcumin, Groundnut Oil, Cremephor RH, and Tween 80. Self-micro emulsification time, zeta potential, droplet size, polydispersity index, transmission electron microscopy, drug release, and in-vivo studies were performed for characterization. The globule size was found to be 25.59±0.40 nm and the zeta potential was-5.75±0.18 mV. The globules prepared were spherical in shape. The in-vitro dissolution performance of formulation of dihydroartemisinin and curcumin self emulsifying drug delivery system showed significantly (p<0.05, Origin Pro 8.5) higher release as compared to the pure drugs. The results of the study suggested that the prepared self emulsifying drug delivery system combination of Dihydroartemesinin and curcumin has a better potential to cure parasitemia as compared to the individual drug.

Adapting Clofazimine for Treatment of Cutaneous Tuberculosis by Using Self-Double-Emulsifying Drug Delivery Systems

Although chemotherapeutic treatment regimens are currently available, and considerable effort has been lavished on the development of new drugs for the treatment of tuberculosis (TB), the disease remains deeply intractable and widespread. This is due not only to the nature of the life cycle and extraordinarily disseminated habitat of the causative pathogen, principally Mycobacterium tuberculosis (Mtb), in humans and the multi-drug resistance of Mtb to current drugs, but especially also to the difficulty of enabling universal treatment of individuals, immunocompromised or otherwise, in widely differing socio-economic environments. For the purpose of globally eliminating TB by 2035, the World Health Organization (WHO) introduced the "End-TB" initiative by employing interventions focusing on high impact, integrated and patient-centered approaches, such as individualized therapy. However, the extraordinary shortfall in stipulated aims, for example in actual treatment and in TB preventative treatments during the period 2018-2022, latterly and greatly exacerbated by the COVID-19 pandemic, means that even greater pressure is now placed on enhancing our scientific understanding of the disease, repurposing or repositioning old drugs and developing new drugs as well as evolving innovative treatment methods. In the specific context of multidrug resistant Mtb, it is furthermore noted that the incidence of extra-pulmonary TB (EPTB) has significantly increased. This review focusses on the potential of utilizing self-double-emulsifying drug delivery systems (SDEDDSs) as topical drug delivery systems for the dermal route of administration to aid in treatment of cutaneous TB (CTB) and other mycobacterial infections as a prelude to evaluating related systems for more effective treatment of CTB and other mycobacterial infections at large. As a starting point, we consider here the possibility of adapting the highly lipophilic riminophenazine clofazimine, with its potential for treatment of multi-drug resistant TB, for this purpose. Additionally, recently reported synergism achieved by adding clofazimine to first-line TB regimens signifies the need to consider clofazimine. Thus, the biological effects and pharmacology of clofazimine are reviewed. The potential of plant-based oils acting as emulsifiers, skin penetration enhancers as well as these materials behaving as anti-microbial components for transporting the incorporated drug are also discussed.

Gastroretentive Sustained-Release Tablets Combined with a Solid Self-Micro-Emulsifying Drug Delivery System Adsorbed onto Fujicalin®

Gastroretentive drug delivery systems (GRDDS) get retained in the stomach for a long time, thus facilitating the absorption of drugs in the upper gastrointestinal tract. However, drugs that are difficult to dissolve or unstable in an acidic environment are not suitable for GRDDS. The current study designs GRDDS combined with a self-micro-emulsifying drug delivery system (SMEDDS) for drugs with solubility or stability problems in the stomach. The model drug fenofibrate was formulated into the optimized liquid SMEDDS composed of 50 w/w% Capryol^® PGMC, 40 w/w% Kolliphor^® RH40, and 10 w/w% Transcutol^® HP and solidified through adsorption on several porous adsorbents. In a dissolution medium at pH 1.2, the powdered SMEDDS using Fujicalin^® dissolved quickly and achieved higher drug dissolution than other adsorbents. Based on these results, a gastroretentive bilayer tablet consisting of a drug release layer and a swelling layer was designed. The drug release layer was formulated with the powdered SMEDDS and hydroxypropyl methylcellulose (HPMC) as a release modifier. HPMC was also added to the swelling layer as a water-swellable polymer. The dissolution rate depended on the viscosity of the HPMC in the drug release layer. The time for 90% drug release was extended from 3.7 to 12.0 h by increasing the viscosity grade of HPMC from 0.1 to 100 K. Moreover, the tablet swelled and maintained a size comparable to a human pylorus diameter or more for at least 24 h. This GRDDS could apply to a broader range of drug candidates.

A Comprehensive Insight on Self Emulsifying Drug Delivery Systems

BACKGROUND

The oral route is a highly recommended route for the delivery of a drug. But most lipophilic drugs are difficult to deliver via this route due to their low aqueous solubility. Selfemulsifying drug delivery systems (SEDDS) have emerged as a potential approach of increasing dissolution of a hydrophobic drug due to spontaneous dispersion in micron or nano sized globules in the GI tract under mild agitation.

OBJECTIVE

The main motive of this review article is to describe the mechanisms, advantages, disadvantages, factors affecting, effects of excipients, possible mechanisms of enhancing bioavailability, and evaluation of self-emulsifying drug delivery systems.

RESULTS

Self emulsifying systems incorporate the hydrophobic drug inside the oil globules, and a monolayer is formed by surfactants to provide the low interfacial tension, which leads to improvement in the dissolution rate of hydrophobic drugs. The globule size of self-emulsifying systems depends upon the type and ratio of excipients in which they are used. The ternary phase diagram is constructed to find out the range of concentration of excipients used. This review article also presents recent and updated patents on self-emulsifying drug delivery systems. Self-emulsifying systems have the ability to enhance the oral bioavailability and solubility of lipophilic drugs.

CONCLUSION

This technique offers further advantages such as bypassing the first pass metabolism via absorption of drugs through the lymphatic system, easy manufacturing, reducing enzymatic hydrolysis, inter and intra subject variability, and food effects.

Chinese Herbal Medicine for Primary Liver Cancer Therapy: Perspectives and Challenges

Primary liver cancer (PLC) is one of the most common solid malignancies. However, PLC drug development has been slow, and first-line treatments are still needed; thus, studies exploring and developing alternative strategies for effective PLC treatment are urgently needed. Chinese herbal medicine (CHM) has long been applied in the clinic due to its advantages of low toxicity and targeting of multiple factors and pathways, and it has great potential for the development of novel natural drugs against PLC.

Purpose: This review aims to provide an update on the pharmacological mechanisms of Chinese patent medicines (CPMs) and the latest CHM-derived compounds for the treatment of PLC and relevant clinical evaluations.

Materials and Methods: A systematic search of English literature databases, Chinese literature, the Clinical Trials Registry Platform, and the Chinese Clinical Trial Registry for studies of CHMs for PLC treatment was performed.

Results: In this review, we summarize the clinical trials and mechanisms of CPMs for PLC treatment that have entered the clinic with the approval of the Chinese medicine regulatory authority. These CPMs included Huaier granules, Ganfule granules, Fufang Banmao capsules, Jinlong capsules, Brucea javanica oil emulsions, and compound kushen injections. We also summarize the latest in vivo, in vitro, and clinical studies of CHM-derived compounds against PLC: icaritin and ginsenoside Rg3. Dilemmas facing the development of CHMs, such as drug toxicity and low oral availability, and future developments are also discussed.

Conclusion: This review provides a deeper the understanding of CHMs as PLC treatments and provides ideas for the development of new natural drugs against PLC.

A Customized Screening Tool Approach for the Development of a Self-Nanoemulsifying Drug Delivery System (SNEDDS)

The present study focused on establishing a novel, (pre-)screening approach that enables the development of promising performing self-nanoemulsifying drug delivery systems (SNEDDSs) with a limited number of experiments. The strategic approach was based on first identifying appropriate excipients (oils/lipids, surfactants, and co-solvents) providing a high saturation solubility for lipophilic model compounds with poor aqueous solubility. Excipients meeting these requirements were selected for SNEDDS development, and a special triangular mixture design was applied for determining excipient ratios for the SNEDDS formulations. Celecoxib and fenofibrate were used as model drugs. Formulations were studied applying a specific combination of in vitro characterization methods. Specifications for a promising SNEDDS formulation were self-imposed: a very small droplet size (< 50 nm), a narrow size distribution of these droplets (PDI < 0.15) and a high transmittance following SNEDDS dispersion in water (> 99% in comparison with purified water). Excipients that provided a nanoemulsion after dispersion were combined, and ratios were optimized using a customized mapping method in a triangular mixture design. The best performing formulations were finally studied for their in vitro release performance. Results of the study demonstrate the efficiency of the customized screening tool approach. Since it enables successful SNEDDS development in a short time with manageable resources, this novel screening tool approach could play an important role in future SNEDDS development.

Drug Delivery Strategies for Curcumin and Other Natural Nrf2 Modulators of Oxidative Stress-Related Diseases

Oxidative stress is associated with a wide range of diseases characterised by oxidant-mediated disturbances of various signalling pathways and cellular damage. The only effective strategy for the prevention of cellular damage is to limit the production of oxidants and support their efficient removal. The implication of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the cellular redox status has spurred new interest in the use of its natural modulators (e.g., curcumin, resveratrol). Unfortunately, most natural Nrf2 modulators are poorly soluble and show extensive pre-systemic metabolism, low oral bioavailability, and rapid elimination, which necessitates formulation strategies to circumvent these limitations. This paper provides a brief introduction on the cellular and molecular mechanisms involved in Nrf2 modulation and an overview of commonly studied formulations for the improvement of oral bioavailability and in vivo pharmacokinetics of Nrf2 modulators. Some formulations that have also been studied in vivo are discussed, including solid dispersions, self-microemulsifying drug delivery systems, and nanotechnology approaches, such as polymeric and solid lipid nanoparticles, nanocrystals, and micelles. Lastly, brief considerations of nano drug delivery systems for the delivery of Nrf2 modulators to the brain, are provided. The literature reviewed shows that the formulations discussed can provide various improvements to the bioavailability and pharmacokinetics of natural Nrf2 modulators. This has been demonstrated in animal models and clinical studies, thereby increasing the potential for the translation of natural Nrf2 modulators into clinical practice.

Microemulsions: Unique Properties, Pharmacological Applications, and Targeted Drug Delivery

Microemulsions, comprising oil, water and a surfactant, in association with some co-surfactant, are thermodynamically stable systems. They have found applications in a large number of chemical and pharmacological processes due to their unique properties such as large interfacial area, low interfacial tension, and most importantly, the ability to solubilize and deliver hydrophobic drugs. In addition to the oral and intravenous route, they are suitable for drug delivery through the ophthalmic, vaginal, pulmonary, dental, and topical routes. This review highlights the properties and several recent developments in the use of microemulsions for medical treatment purposes including targeted drug delivery.

Self-nanoemulsifying Drug Delivery System: A Versatile Carrier for Lipophilic Drugs

BACKGROUND

Lipid-based systems such as self-nanoemulsifying drug delivery systems (SNEDDS) have resurged the eminence of nanoemulsions and offer many useful drug delivery opportunities. In the modern drug discovery era, there is a constant increase in the number of poorly soluble new chemical entities that suffer from poor and erratic bioavailability problems. The oral route possesses some major disadvantages, such as lack of constant drug levels in plasma, firstpass metabolism, which results in poor bioavailability. To address these problems, various lipidbased therapeutic systems are available from which self-enanoemulsifying systems have the potential to increase the bioavailability of poorly soluble drugs.

METHODS

SNEDDS is the isotropic mixture of oils, surfactant, and co-surfactant having droplet size in the range of 100-200 nm, which spontaneously emulsifies when it contacts with aqueous media in gastrointestinal (G.I) fluid. Various preparative methods are available for SNEDDS, such as high-pressure homogenizer, microfluidization, sonication, phase inversion, and shear state methods. These methods show favorable benefits in drug delivery. Self-nanoemulsifying drug delivery system possesses some disadvantages like precipitation of drug in G.I fluid or possible drug leaving in the capsule dosage form due to incompatibility issues, which can be overcome by more advanced techniques like supersaturated SNEDDS containing a precipitation inhibitor or Solid SNEDDS. These areformulated either through spray drying or using a solid carrier.

CONCLUSION

The lipid-based nanocarrier (SNEDDS) plays a significant role in drug delivery to overcome the poor solubility and oral bioavailability. This review highlights the elaborative aspects of the diverse advantages of SNEDDS based formulations.

The Evaluation of Drug Delivery Nanocarrier Development and Pharmacological Briefing for Metabolic-Associated Fatty Liver Disease (MAFLD): An Update

Current research indicates that the next silent epidemic will be linked to chronic liver diseases, specifically non-alcoholic fatty liver disease (NAFLD), which was renamed as metabolic-associated fatty liver disease (MAFLD) in 2020. Globally, MAFLD mortality is on the rise. The etiology of MAFLD is multifactorial and still incompletely understood, but includes the accumulation of intrahepatic lipids, alterations in energy metabolism, insulin resistance, and inflammatory processes. The available MAFLD treatment, therefore, relies on improving the patient's lifestyle and multidisciplinary pharmacotherapeutic options, whereas the option of surgery is useless without managing the comorbidities of the MAFLD. Nanotechnology is an emerging approach addressing MAFLD, where nanoformulations are suggested to improve the safety and physicochemical properties of conventional drugs/herbal medicines, physical, chemical, and physiological stability, and liver-targeting properties. A wide variety of liver nanosystems were constructed and delivered to the liver, only those that addressed the MAFLD were discussed in this review in terms of the nanocarrier classes, particle size, shape, zeta potential and offered dissolution rate(s), the suitable preparation method(s), excipients (with synergistic effects), and the suitable drug/compound for loading. The advantages and challenges of each nanocarrier and the focus on potential promising perspectives in the production of MAFLD nanomedicine were also highlighted.

Abdulbaqi I, Seok Ming T, Siok Yee C, A. Wahab H, Asif SM, Darwis Y. Liquid and Solid Self-Emulsifying Drug Delivery Systems (SEDDs) as Carriers for the Oral Delivery of Azithromycin: Optimization, In Vitro Characterization and Stability Assessment

Azithromycin (AZM) is a macrolide antibiotic used for the treatment of various bacterial infections. The drug is known to have low oral bioavailability (37%) which may be attributed to its relatively high molecular weight, low solubility, dissolution rate, and incomplete intestinal absorption. To overcome these drawbacks, liquid (L) and solid (S) self-emulsifying drug delivery systems (SEDDs) of AZM were developed and optimized. Eight different pseudo-ternary diagrams were constructed based on the drug solubility and the emulsification studies in various SEDDs excipients at different surfactant to co-surfactant (Smix) ratios. Droplet size (DS) < 150 nm, dispersity (Đ) ≤ 0.7, and transmittance (T)% > 85 in three diluents of distilled water (DW), 0.1 mM HCl, and simulated intestinal fluids (SIF) were considered as the selection criteria. The final formulations of L-SEDDs (L-F1(H)), and S-SEDDs (S-F1(H)) were able to meet the selection requirements. Both formulations were proven to be cytocompatible and able to open up the cellular epithelial tight junctions (TJ). The drug dissolution studies showed that after 5 min > 90% and 52.22% of the AZM was released from liquid and solid SEDDs formulations in DW, respectively, compared to 11.27% of the pure AZM, suggesting the developed SEDDs may enhance the oral delivery of the drug. The formulations were stable at refrigerator storage conditions.

Antifungal Activity and the Chemical and Physical Stability of Microemulsions Containing Citrus hystrix DC Leaf Oil

Citrus hystrix DC (kaffir lime) leaf oil exhibited antifungal activities against Aspergillus niger and Candida albicans. This study aimed to evaluate the antifungal activity of kaffir lime leaf oil and microemulsions containing kaffir lime oil against Trichophyton mentagrophytes var. interdigitale. The chemical components of kaffir lime leaf oil were analyzed by gas chromatography coupled with mass spectrometry. Microemulsions containing kaffir lime oil were formulated using Tween 80, propylene glycol, and water using a phase titration method. The microemulsion of kaffir lime leaf oil was evaluated for droplet size, polydispersity index, and zeta potential using a dynamic light scattering technique. The antifungal activities of kaffir lime oil and its microemulsion were investigated through macrodilution and agar well diffusion methods, respectively. The degradation of citronellal in the microemulsion was analyzed by validated UV-Visible spectrophotometry. The minimum inhibitory concentration value of kaffir lime oil was 1.08 ± 0.00 mg/mL. The microemulsion of kaffir lime leaf oil exhibited potent antifungal activity against T. mentagrophytes var. interdigitale. The size, polydispersity index, and zeta potential of freshly prepared microemulsion were 12.82 ± 0.40 nm, 0.183 ± 0.072, and −7.87 ± 0.06 mV, respectively. The microemulsion of kaffir lime leaf oil also demonstrated good physical and chemical stability at specific temperatures. The kaffir lime oil microemulsion was highly stable when stored at 4 °C and 30 °C for 1 month but was unstable at 45 °C. The microemulsion of kaffir lime leaf oil may be an alternative therapeutic against tinea pedis caused by T. mentagrophytes var. interdigitale.

Development and in vitro Evaluation of Gastro-protective Aceclofenac-loaded Self-emulsifying Drug Delivery System

AIM

Chronic use of oral nonsteroidal anti-inflammatory drugs (NSAIDs) is commonly associated with gastric irritation and gastric ulceration. Therefore, the aim of study was to develop a novel oral drug delivery system with minimum gastric effects and improved dissolution rate for aceclofenac (ACF), a model BCS class-II drug.

METHODS

Self-emulsifying drug delivery systems (SEDDS) were formulated to increase the solubility and ultimately the oral bioavailability of ACF. Oleic acid was used as an oil phase, Tween 80 (T80) and Kolliphor EL (KEL) were used as surfactants, whereas, polyethylene glycol 400 (PEG 400) and propylene glycol (PG) were employed as co-surfactants. Optimized formulations (F1, F2, F3 and F4) were analyzed for droplet size, poly dispersity index (PDI), cell viability studies, in vitro dissolution in both simulated gastric fluid and simulated intestinal fluid, ex vivo permeation studies and thermodynamic stability.

RESULTS

The optimized formulations showed mean droplet sizes in the range of 111.3 ± 3.2 nm and 470.9 ± 12.52 nm, PDI from 244.6 nm to 389.4 ± 6.51 and zeta-potential from -33 ± 4.86 mV to -38.5 ± 5.15 mV. Cell viability studies support the safety profile of all formulations for oral administration. The in vitro dissolution studies and ex vivo permeation analysis revealed significantly improved drug release ranging from 95.68 ± 0.02% to 98.15 ± 0.71% when compared with control. The thermodynamic stability studies confirmed that all formulations remain active and stable for a longer period.

CONCLUSION

In conclusion, development of oral SEDDS might be a promising tool to improve the dissolution of BCS class-II drugs along with significantly reduced exposure to gastric mucosa.

Development of a Self-Emulsifying Drug Delivery System for Optimized Topical Delivery of Clofazimine

A quality-by-design and characterization approach was followed to ensure development of self-emulsifying drug delivery systems (SEDDSs) destined for topical delivery of the highly lipophilic clofazimine. Solubility and water-titration experiments identified spontaneous emulsification capacity of different excipient combinations and clofazimine. After identifying self-emulsification regions, check-point formulations were selected within the self-emulsification region by considering characteristics required to achieve optimized topical drug delivery. Check-point formulations, able to withstand phase separation after 24 h at an ambient temperature, were subjected to characterization studies. Experiments involved droplet size evaluation; size distribution; zeta-potential; self-emulsification time and efficacy; viscosity and pH measurement; cloud point assessment; and thermodynamic stability studies. SEDDSs with favorable properties, i.e., topical drug delivery, were subjected to dermal diffusion studies. Successful in vitro topical clofazimine delivery was observed. Olive oil facilitated the highest topical delivery of clofazimine probably due to increased oleic acid levels that enhanced stratum corneum lipid disruption, followed by improved dermal clofazimine delivery. Finally, isothermal microcalometric experiments studied the compatibility of excipients. Potential interactions were depicted between argan oil and clofazimine as well as between Span®60 and argan-, macadamia- and olive oil, respectively. However, despite some mundane incompatibilities, successful development of topical SEDDSs achieved enhanced topical clofazimine delivery.

Enhancement of in vivo hypoglycemic effect of gliclazide by developing self-microemulsifying pellet dosage form

Background

The present research was aimed to develop a self-microemulsifying drug delivery system (SMEDDS) pellet to increase the dissolution rate and in vivo hypoglycemic effect of gliclazide. Gliclazide belongs to BCS class 2 and it exhibits dissolution rate-limited absorption. Thus, dissolution enhancement of gliclazide from its dosage form is a prime requirement to achieve a better therapeutic effect. The solubility of gliclazide was estimated in oils, surfactants, and co-surfactants. A most effective self-emulsification region was identified using pseudoternary phase diagrams. The optimized liquid SMEDDS gliclazide formulation was converted to SMEDDS pellets using the extrusion-spheronization technique. The in vitro release and hypoglycemic effect of SMEDDS was compared with the marketed product.

Results

The optimized liquid gliclazide SMEDDS formulations contained mixtures of Tween 80 and PEG 400 and Capmul MCM C8. The gliclazide SMEDDS in liquid preparation quickly formed a fine oil-in-water microemulsion having a globule size of 31.50 nm. In vitro release of gliclazide from SMEDDS pellets was 100.9% within 20 min. SMEDDS pellets exhibited a significant reduction in plasma glucose levels in albino mice compared to the marketed product.

Conclusion

The results indicated that SMEDDS pellets could be effectively used to improve the oral delivery of gliclazide.

A Mixed Micellar Formulation for the Transdermal Delivery of an Indirubin Analog

Indirubin is an active component of Dang Gui Long Hui Wan, which has been used in traditional Chinese medicine to treat inflammatory diseases as well as for the prevention and treatment of human cancer, such as chronic myeloid leukemia. The therapeutic effects of indirubin analogs have been underestimated due to its poor water solubility and low bioavailability. To improve the solubility and bioavailability of indirubin analogs, we prepared a mixed micellar formulation with Kolliphor® EL and Tween 80 as surfactants, and PEG 400 as a co-surfactant, followed by complexation with (2-hydroxyproply)-β-cyclodextrin at appropriate ratios. Overall, improving the solubility and skin penetration of indirubin analogs can increase clinical efficacy and provide maximum flux through the skin.

Carotenoid-loaded nanocarriers: A comprehensive review

Carotenoids retain plenty of health benefits and attracting much attention recently, but they have less resistance to processing stresses, easily oxidized and chemically unstable. Additionally, their application in food and pharmaceuticals are restricted due to some limitations such as poor bioavailability, less solubility and quick release. Nanoencapsulation techniques can be used to protect the carotenoids and to uphold their original characteristics during processing, storage and digestion, improve their physiochemical properties and enhance their health promoting effects. The importance of nanocarriers in foods and pharmaceuticals cannot be denied. This review comprehensively covers recent advances in nanoencapsulation of carotenoids with biopolymeric nanocarriers (polysaccharides and proteins), and lipid-based nanocarriers, their functionalities, aptness and innovative developments in preparation strategies. Furthermore, the present state of the art encapsulation of different carotenoids via biopolymeric and lipid-based nanocarriers have been enclosed and tabulated well. Nanoencapsulation has a vast range of applications for protection of carotenoids. Polysaccharides in combination with different proteins can offer a great avenue to achieve the desired formulation for encapsulation of carotenoids by using different nanoencapsulation strategies. In terms of lipid based nanocarriers, solid lipid nanoparticles and nanostructure lipid carriers are proving as the encouraging candidates for entrapment of carotenoids. Additionally, nanoliposomes and nanoemulsion are also promising and novel-vehicles for the protection of carotenoids against challenging aspects as well as offering an effectual controlled release on the targeted sites. In the future, further studies could be conducted for exploring the application of nanoencapsulated systems in food and gastrointestinal tract (GIT) for industrial applications.

Formulation and In Vitro Evaluation of Self Microemulsifying Drug Delivery System Containing Atorvastatin Calcium

OBJECTIVE

The aim of this study was to develop a new dosage form as an alternative to the classical tablet forms of atorvastatin calcium (AtrCa). The formulation strategy was to prepare an optimum self micro emulsifying drug delivery system (SMEDDS) to overcome the problem of low solubility of the active substance.

METHODS

In this study, pseudo ternary phase diagrams were plotted determined by the solubility studies. According to the solubility studies; oleic acid was used as the oil phase, Tween 20 and Span 80 were used as the surfactants and ethanol was used as the co-surfactant. SMEDDS formulations were characterized according to pH, electrical conductivity, density, refractive index, viscosity, emulsification time, dispersibility, robustness of dilution stability, droplet size, polidispersity index, zeta potential, transmittance %, cloud point, content quantification %, chemical and physical stability. The lipolysis study was conducted under fed and fasted conditions. In vitro release studies and kinetic evaluation were carried out. Permeability studies were also examined with Caco-2 cell culture.

RESULTS

The droplet size of the optimized formulation did not change significantly in different medias over the test time period. Improved SMEDDS formulation will progress steadily without precipitating along the gastrointestinal tract. Lipolysis studies showed that the oil solution had been exposed to high amount of lipolysis compared to the SMEDDS formulation. The release rate of AtrCa from AtrCa- SMEDDS formulation (93.8%, at 15 minutes) was found as increased when the results were compared with commercial tablet formulation and pure drug. The permeability value of AtrCa from AtrCa- SMEDDS formulation was found higher than pure AtrCa and commercial tablet formulation, approximately 9.94 and 1.64 times, respectively.

CONCLUSION

Thus, lipid-based SMEDDS formulation is a potential formulation candidate for lymphatic route in terms of the increased solubility of AtrCa.

Self Emulsifying Drug Delivery System: A Recent Approach

In recent years, nearly 40 % newer drugs compounds are hydrophobic in nature, which is a major challenge now-a-days for oral drug delivering due to low aqueous solubility. Lipid based drug delivery system is one of the favourable approach for poorly soluble compounds which can improve the drug absorption and oral bioavailability. Due to ion-pairing with appropriate surfactant and co-surfactant the macromolecular drug molecular oil droplet being found in the gut flow oral absorption which sufficiently stable towards lipase. Due to the formation of emulsified drug in micron level, it can efficiently endow the oral bioavailability. Several comprehensive papers have been published in the literature illustration diverse type of lipid based formulation with recent advancements. This article is based on an exhaustive and updated review on newer technology which out line an explicit discussion on its formulations and industrial scale up.

Strategic approach to developing a self-microemulsifying drug delivery system to enhance antiplatelet activity and bioavailability of ticagrelor

Background

Ticagrelor (TCG) is used to inhibit platelet aggregation in patients with acute coronary syndrome, but its poor solubility and low bioavailability limit its in vivo efficacy. The purpose of this study was to manufacture an optimized TCG-loaded self-microemulsifying drug delivery system (SMEDDS) to enhance the oral bioavailability and antiplatelet activity of TCG.

Materials and methods

Solubility and emulsification tests were conducted to determine the most suitable oils, surfactants, and cosurfactants. Scheffé's mixture design was applied to optimize the percentage of each component applied in the SMEDDS formulation to achieve optimal physical characteristics, ie, high solubility of TCG in SMEDDS, small droplet size, low precipitation, and high transmittance.

Results

The optimized TCG-loaded SMEDDS (TCG-SM) formulation composed of 10.0% Capmul MCM (oil), 53.8% Cremophor EL (surfactant), and 36.2% Transcutol P (cosurfactant) significantly improving the dissolution of TCG in various media compared with TCG in Brilinta^® (commercial product). TCG-SM exhibited higher cellular uptake and permeability in Caco-2 cells than raw TCG suspension. In pharmacokinetic studies in rats, TCG-SM exhibited higher oral bioavailability with 5.7 and 6.4 times higher area under the concentration-time curve and maximum plasma concentration, respectively, than a raw TCG suspension. Antiplatelet activity studies exhibited that the TCG-SM formulation showed significantly improved inhibition of platelet aggregation compared with raw TCG at the same dose of TCG. And, a 10 mg/kg dose of raw TCG suspension and a 5 mg/kg dose of TCG-SM had a similar area under the inhibitory curve (907.0%±408.8% and 907.8%±200.5%⋅hours, respectively) for antiplatelet activity.

Conclusion

These results suggest that the developed TCG-SM could be successfully used as an efficient method to achieve the enhanced antiplatelet activity and bioavailability of TCG.

Development and In Vivo Evaluation of Ziyuglycoside I-Loaded Self-Microemulsifying Formulation for Activity of Increasing Leukocyte

Ziyuglycoside I (ZgI), a major effective ingredient of Sanguisorba officinalis L, has shown good activity in increasing leukocyte of myelosuppression mice. However, oral ZgI therapy has been deterred by poor bioavailability because of its low aqueous solubility and permeability. Our study was to develop ZgI-loaded self-microemulsifying drug delivery system (SMEDDS) and evaluate its intestinal absorption, and pharmacokinetic and pharmacodynamic activity for increasing leukocyte. The formulation was designed and optimized by measuring the equilibrium solubility of ZgI in different vehicles and the pseudoternary phase diagram. Further, morphology, particle size, stability, in vitro release, in situ single-pass intestinal perfusion (SPIP), in vivo activity, and in vivo pharmacokinetic (PK) of ZgI-SMEDDS were charactered or studied. Optimized formulations for in vitro dissolution were Obleique CC497, Tween-20, and Transcutol HP with a proportion of 0.25/0.45/0.30 via D-optimal mixture design. Results showed that the solubility of ZgI was enhanced up to 23.93 mg/g and its average particle size was 207.92 ± 2.13 nm. The release of ZgI had been greatly improved by the SMEDDS. In SPIP, the intestinal absorption of SMEDDS was much better than plain ZgI. In PK, we found the oral bioavailability of ZgI-SMEDDS was 6.94-fold higher absolute bioavailability (21.94 ± 4.67) % than ZgI (3.16 ± 0.89) %. The most important was that the mice WBC of ZgI-SMEDDS group was significantly higher than that of the ZgI group. Our study suggested that SMEDDS could increase the solubility of ZgI, which was beneficial to improve oral bioavailability and enhance biological activity.

Use of Lipid Nanocarriers to Improve Oral Delivery of Vitamins

The chemical environment and enzymes in the gastrointestinal (GI) membrane limit the oral absorption of some vitamins. The GI epithelium also contributes to the poor permeability of numerous antioxidant agents. Thus, lipophilic vitamins do not readily dissolve in the GI tract, and therefore they have low bioavailability. Nanomedicine has the potential to improve the delivery efficiency of oral vitamins. In particular, the use of lipid nanocarriers for certain vitamins that are administered orally can provide improved solubility, chemical stability, epithelium permeability and bioavailability, half-life, nidus targeting, and fewer adverse effects. These lipid nanocarriers include self-emulsifying drug delivery systems (SEDDSs), nanoemulsions, microemulsions, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs). The use of nontoxic excipients and sophisticated material engineering of lipid nanosystems allows for control of the physicochemical properties of the nanoparticles and improved GI permeation via mucosal or lymphatic transport. In this review, we highlight recent progress in the development of lipid nanocarriers for vitamin delivery. In addition, the same lipid nanocarriers used for vitamins may also be effective as carriers of vitamin derivatives, and therefore enhance their oral bioavailability. One example is the incorporation of d-α-tocopheryl polyethylene glycol succinate (TPGS) as the emulsifier in lipid nanocarriers to increase the solubility and inhibit P-glycoprotein (P-gp) efflux. We also survey the concepts and discuss the mechanisms of nanomedical techniques that are used to develop vitamin-loaded nanocarriers.

Self-nanomicellizing solid dispersion of edaravone: part I - oral bioavailability improvement

Background

Edaravone (EDR) is known for its free radical scavenging, antiapoptotic, antinecrotic, and anticytokine effects in neurological and non-neurological diseases. It is currently available clinically as Radicava^® and Radicut^®, intravenous medications, recently approved for the treatment of amyotrophic lateral sclerosis and cerebral infarction. However, the oral use of EDR is still restricted by its poor oral bioavailability (BA) due to poor aqueous solubility, stability, rapid metabolism, and low permeability. The present study reports the development of novel EDR formulation (NEF) using self-nanomicellizing solid dispersion (SNMSD) strategy with the aim to enable its oral use.

Materials and methods

The selection of a suitable carrier for the development of NEF was performed based on the miscibility study. The optimization of EDR-to-carrier ratio was conducted via kinetic solubility study after preparing SNMSDs using solvent evaporation technique. The drug–polymer carrier interaction and self-nanomicellizing properties of NEF were investigated with advanced characterization studies. In vitro permeation, metabolism, and dissolution study was carried out to examine the effect of the presence of a carrier on physico-chemical properties of EDR. Additionally, the dose-dependent pharmacokinetic study of NEF was conducted and compared with the EDR suspension.

Results

Soluplus^® (SOL) as a carrier was selected based on the potential for improving aqueous solubility. The NEF containing EDR and SOL (1:5) resulted in the highest enhancement in aqueous solubility (17.53-fold) due to amorphization, hydrogen bonding interaction, and micellization. Moreover, the NEF demonstrated significant improvement in metabolism, permeability, and dissolution profile of EDR. Furthermore, the oral BA of NEF showed 10.2-, 16.1-, and 14.8-fold enhancement compared to EDR suspension at 46, 138, and 414 µmol/kg doses.

Conclusion

The results demonstrated that SNMSD strategy could serve as a promising way to enhance EDR oral BA and NEF could be a potential candidate for the treatment of diseases in which oxidative stress plays a key role in their pathogenesis.

Role of Components in the Formation of Self-microemulsifying Drug Delivery Systems

Pharmaceutical research is focused in designing novel drug delivery systems to improve the bioavailability of poorly water soluble drugs. Self-microemulsifying drug delivery systems, one among the lipid-based dosage forms were proven to be promising in improving the oral bioavailability of such drugs by enhancing solubility, permeability and avoiding first-pass metabolism via enhanced lymphatic transport. Further, they have been successful in avoiding both inter and intra individual variations as well as the dose disproportionality. Aqueous insoluble drugs, in general, show greater solubility in lipid based excipients, and hence they are formulated as lipid based drug delivery systems. The extent of solubility of a hydrophobic drug in lipid excipients i.e. oil, surfactant and co-surfactant (components of self-microemulsifying drug delivery systems) greatly affects the drug loading and in producing stable self-microemulsifying drug delivery systems. The present review highlighted the influence of physicochemical factors and structural features of the hydrophobic drug on its solubility in lipid excipients and an attempt was made to explore the role of each component of self-microemulsifying drug delivery systems in the formation of stable microemulsion upon dilution.