Ethosomes-based topical delivery system of antihistaminic drug for treatment of skin allergies

Ethosomes as a carrier for transdermal drug delivery system: methodology and recent developments

Transdermal drug delivery systems (TDDS) have received significant attention in recent years. TDDS are flexible systems that transport active components to the skin for either localized or systemic delivery of drugs through the skin. Among the three main layers of skin, the outermost layer, called the stratum corneum (SC), prevents the entry of water-loving bacteria and drugs with a high molecular weight. The challenge lies in successfully delivering drugs through the skin, which crosses the stratum corneum. The popularity of lipid-based vesicular delivery systems has increased in recent years due to their ability to deliver both hydrophilic and hydrophobic drugs. Ethosomes are specialized vesicles made of phospholipids that can store large amounts of ethanol. Ethosome structure and substance promote skin permeability and bioavailability. This article covers ethosome compositions, types, medication delivery techniques, stability, and safety. In addition to this, an in-depth analysis of the employment of ethosomes in drug delivery applications for a wide range of diseases has also been discussed. This review article highlights different aspects of ethosomes, such as their synthesis, characterization, marketed formulation, recent advancements in TDDS, and applications.

Bacteria-based drug delivery for treating non-oncological diseases

Bacteria inhabit all over the human body, especially the skin, gastrointestinal tract, respiratory tract, urogenital tract, as well as specific lesion sites, such as wound and tumor. By leveraging their distinctive attributes including rapid proliferation, inherent abilities to colonize various biointerfaces in vivo and produce diverse biomolecules, and the flexibility to be functionalized via genetic engineering or surface modification, bacteria have been widely developed as living therapeutic agents, showing promising potential to make a great impact on the exploration of advanced drug delivery systems. In this review, we present an overview of bacteria-based drug delivery and its applications in treating non-oncological diseases. We systematically summarize the physiological positions where living bacterial therapeutic agents can be delivered to, including the skin, gastrointestinal tract, respiratory tract, and female genital tract. We discuss the success of using bacteria-based drug delivery systems in the treatment of diseases that occur in specific locations, such as skin wound healing/infection, inflammatory bowel disease, respiratory diseases, and vaginitis. We also discuss the advantages as well as the limitations of these living therapeutics and bacteria-based drug delivery, highlighting the key points that need to be considered for further translation. This review article may provide unique insights for designing next-generation bacteria-based therapeutics and developing advanced drug delivery systems.

Encapsulation of alpha arbutin, a depigmenting agent, in nanosized ethosomes: Invitro and invivo human studies

Alpha arbutin is a skin-whitening agent in cosmetics. Structurally, it is 4-hydroxyphenyl-α-glucopyranoside. Ethosomes encourage the formation of lamellar-shaped vesicles with improved solubility and entrapment of whitening agents. The objective of this study was to fabricate an optimized nanostructured ethosomal gel loaded with alpha arbutin for the treatment of skin pigmentation. Different ethosomal suspensions of alpha arbutin were prepared by the cold method. Invitro evaluation included zeta potential, droplet size analysis, polydispersity index, entrapment efficiency (EE), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Stability studies of the optimized ethosomal and control gels were performed for three months under different temperature conditions. The optimized ethosomal gel loaded with alpha arbutin was further analyzed on human volunteers for skin benefits by measuring melanin level, moisture content and elasticity. It was concluded that the optimized formulation had a size, zeta potential, polydispersity index and entrapment efficiency of 196.87 nm, -45.140 mV, 0.217 and 93.458343%, respectively. Scanning electron microscopy (SEM) depicted spherical ethosomal vesicles. Stability data was obtained in terms of pH and conductivity. Rheological analysis revealed non-Newtonian flow. The cumulative drug permeated for ethosomal gel was 78.4%. Moreover, encapsulation of alpha arbutin causes significant improvement in skin melanin, moisture content and elasticity. The overall findings suggested that the arbutin-loaded ethosomal formulation was stable and could be a better approach than conventional formulation for cosmeceutical purposes such as for depigmentation and moisturizing effects.

Transethosomes: Cutting edge approach for drug permeation enhancement in transdermal drug delivery system

The skin is a major route of drug administration. Despite the high surface area of the skin, drug delivery via the skin route is problematic due to its physiological obstacles. The formulation scientist has developed a vesicular system to enhance the skin's absorption of bioactive substances. Among numerous vesicular systems, concept of transethosomes (TEs) introduced in 2012 are being tested for drug delivery to the dermis. When transferosomes and ethosomes interact, TEs are produced. It consists of water, ethanol, phospholipids, and an edge activator. Ethanol and the edge activator increase the absorption of medication through the skin. In the presence of ethanol and an edge activator, skin permeability can increase. The advantages of TEs include increased patient compliance, bypassing first-pass metabolism, including non-toxic raw components, being a noninvasive method of drug delivery, being more stable, biocompatible, biodegradable, and administered in semisolid form. TEs can be produced through the use of hot, cold, mechanical dispersion, and conventional techniques. The morphology, shape, size, zeta potential, drug loading efficiency, vesicle yield, biophysical interactions, and stability of TEs define them. Recent studies reported successful transdermal distribution of antifungal, antiviral, anti-inflammatory, and cardiovascular bioactive while using ethosomes with significant deeper penetration in skin. The review extensively discussed various claims on TEs developed by researchers, patents, and marketed ethosomes. However, till today no patens being granted on TEs. There are still lingering difficulties related to ethanol-based TEs that require substantial research to fix.

Potential role of herbal nanoformulations for skin disorders: a review

Aim: In the recent advanced study, the popularity of herbal nano-formulation has gained around the whole world. As we know the reason behind it is that herbal products have comparatively lesser side effects than other synthetic products. Significance: These natural plant extracts have wide medicinal importance as they increase the overall bioavailability of products toward tissues. Key findings: This review provides the use of different herbal nano-formulations, their safety considerations, and the challenges being faced. It also highlights the various Clinical Trials and Patents that are published for skin disorders. Conclusion: The present review describes how the rise of herbal products has made wider interest in transdermal formulations and improve the overall productivity by preventing various skin disorders.

Chitosan-coated alginate (CCA) nanoparticles for augmentation of topical antihistaminic activity of diphenhydramine: in-vitro optimization, skin histopathology and pharmacodynamic studies with in vitro/in vivo correlation

OBJECTIVE

The aim of the present study was to formulate chitosan-coated alginate nanoparticles containing the drug diphenhydramine hydrochloride (DHH).

SIGNIFICANCE

Diphenhydramine hydrochloride (DHH) is the prototype of H₁-antihistaminic drugs. It is a lipophilic drug, that easily crosses the blood-brain barrier when taken orally causing decrements in alertness and performance. Multiple applications of topical drug product are required. Thus, drug incorporation in nanocarriers would increase the skin penetration powers increasing the drug efficacy.

METHODS

Chitosan coated alginate (CCA) nanoparticles were prepared via polyelectrolyte complex technique adopting 2³ full factorial design. Three factors, namely, alginate concentration, drug to alginate ratio and CaCl₂ volume, each in two levels were studied. The prepared formulae were evaluated utilizing entrapment efficiency (EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP) and in vitro release. Characterization process was then followed by optimization.

RESULTS

At alginate conc. of 1%, drug to alginate ratio of 2:1 and CaCl₂ volume of 4 mL, NP8 was chosen as a candidate formula. Histopathological examination on shaved rat dorsal skin disclosed the safety of NP8 with no signs of necrosis or even inflammation. The enhanced topical delivery of diphenhydramine hydrochloride enclosed in the developed nanoparticles was further proved by induction of allergic reaction using intradermal histamine injection. The results revealed the superior ability of NP8 to decrease the diameter of the formed wheal in comparison to marketed DHH product.

CONCLUSION

Thus, CCA nanoparticles are considered as a candidate nanocarriers for fortifying the topical antihistaminic activity of DHH.

Biocompatible phospholipid-based nanovesicular drug delivery system of ketoprofen: Systematic development, optimization, and preclinical evaluation

The present work involved development of phospholipid-based permeation enhancing nanovesicles (PENVs) for topical delivery of ketoprofen. Screening of phospholipids and process parameters was performed. Central composite design was used for optimization of factors, that is, amount (%, w/w) of phospholipid and ethanol at three levels. The optimized nanovesicles (NVs) were loaded with different terpenes and then incorporated into a gel base. Optimized NVs exhibited 69% entrapment efficiency, 51% transmittance, 328 nm mean vesicle size, and polydispersity index of 0.25. In vitro release kinetics evaluation indicated best fitting as per Korsemeyer-Peppa's model and drug release via Fickian-diffusion mechanism. The optimized NVs loaded with mint terpene showed minimal degree of deformability and maximal elasticity as compared with the conventional NVs and liposomes. Rheology and texture analysis indicated pseudoplastic flow and smooth texture of the vesicle gel formulation. Ex vivo permeation studies across Wistar rat skin indicated low penetration (0.43-fold decrease) and high skin retention (4.26-fold increase) of ketoprofen from the optimized PENVs gel vis-à-vis the conventional gel. Skin irritancy study indicated lower scores for PENVs gel construing its biocompatible nature. Stability studies confirmed cold storage is best suitable for vesicle gel, and optimized PENVs were found to be suitable for topical delivery of ketoprofen.

Ethosomes as dermal/transdermal drug delivery systems: applications, preparation and characterization

Transdermal drug delivery systems (TDDSs) have gained substantial attention during the last decade. TDDS are versatile delivery systems in which active components are delivered to skin for local effects or systemic delivery of active pharmaceutical through the skin. Overcoming stratum corneum is the most challenging step of delivering drugs through the skin. Lipid-based vesicular delivery systems due to the capability of the delivery of both hydrophilic and hydrophobic drugs are becoming more popular during the recent years. Ethosomes are innovative, biocompatible, biodegradable and non-toxic form of lipid-based vesicles that efficiently enable to entrap drugs of various physicochemical properties. These are other forms of liposome which contain high amounts of ethanol in their structure that enabling ethosomes to efficiently penetrate through deeper layers of skin. Ethosomes have various compositions based on their type but are mainly composed of phospholipids, ethanol, water and the active components. Ethosomes are easily manufactured and they are superior compared to liposomes in terms of different aspects due to the presence of ethanol. The purpose of this review is to thoroughly focus on various aspects of ethosomes, including mechanism of penetration, advantages and disadvantages, characterisation and applications.

Formulation and Characterization of Metformin-Loaded Ethosomes for Topical Application to Experimentally Induced Skin Cancer in Mice

To achieve the best treatment of skin cancer, drug penetration inside the deepest layers of the skin is an important scientific interest. We designed an ethosome formulation that serves as a carrier for metformin and measured the in vitro skin permeation. We also aimed to measure the antitumor activity of the optimal ethosomal preparation when applied topically to chemically induced skin cancer in mice. We utilized a statistical Box-Behnken experimental design and applied three variables at three levels: lecithin concentration, cholesterol concentration and a mixture of ethanol and isopropyl alcohol concentrations. All formulations were prepared to calculate the entrapment efficiency %, zeta potential, size of the vesicles and drug release % after 1, 2, 4, 8 and 24 h. The size of the vesicles for the formulations was between 124 ± 14.2 nm and 560 ± 127 nm, while the entrapment efficiency was between 97.8 ± 0.23% and 99.4 ± 0.24%, and the drug release % after 8 h was between 38 ± 0.82% and 66 ± 0.52%. All formulations were introduced into the Box-Behnken software, which selected three formulations; then, one was assigned as an optimal formula. The in vivo antitumor activity of metformin-loaded ethosomal gel on skin cancer was greater than the antitumor activity of the gel preparation containing free metformin. Lower lecithin, high ethanol and isopropyl alcohol and moderate cholesterol contents improved the permeation rate. Overall, we can conclude that metformin-loaded ethosomes are a promising remedy for treating skin cancers, and more studies are warranted to approve this activity in other animal models of skin cancers.

Overcoming drug delivery barriers and challenges in topical therapy of atopic dermatitis: A nanotechnological perspective

Atopic dermatitis (AD) is an inflammatory disorder centered around loss of epidermal barrier function, and T helper 2 (Th2) immune responses. The current understanding of disease heterogeneity and complexity, limits the rational use of existing topical, systemic therapeutic agents, but paves way for development of advanced therapeutic agents. Additionally, advanced nanocarriers that deliver therapeutics to target cells, seem to offer a promising strategy, to overcome intrinsic limitations and challenges of conventional, and traditional drug delivery systems. Ever-evolving understanding of molecular target sites and complex pathophysiology, adverse effects of current therapeutic options, inefficient disease recapitulation by existing animal models are some of the challenges that we face. Also, despite limited success in market translatibility, nanocarriers have demonstrated excellent preclinical results and have been extensively studied for AD. Detailed research on behavior of nanocarriers in different patients and tailored therapy to account for phenotypic variability of the disease are the new research avenues that we look forward to.

A Comprehensive Review of Therapeutic Approaches Available for the Treatment of Dermatitis

BACKGROUND

Dermatitis or eczema is a prevalent skin disorder worldwide and is also very common as a pediatric inflammatory skin disorder. Its succession gets worse with the multiple comorbidities which exhibit mechanisms that are poorly understood. Its management further becomes a challenge due to the limited effective treatment options available. However, the Novel Drug Delivery Systems (NDDS) along with new targeting strategies can easily bypass the issues associated with dermatitis management. If we compare the active constituents against phytoconstituents effective against dermatitis then phytoconstituents can be perceived to be more safe and gentle.

OBJECTIVE

Administration of NDDS of plant extract or actives displays improved absorption behavior, which helps them to permeate through lipid-rich biological membrane leading to increased bioavailability. The newer efficient discoveries related to eczema can face various exploitations. This can be intervened by the subjection of patent rights, which not only safeguard the novel works of individual(s) but also give them the opportunity to share details of their inventions with people globally.

CONCLUSION

The present review focuses on the available research about the use of nanoformulations in the topical delivery. It further elaborates the use of different animal models as the basis to characterize the different features of dermatitis. The review also highlights the recent nanoformulations which have the ability to amplify the delivery of active agents through their incorporation in transfersomes, ethosomes, niosomes or phytosomes, etc.

Insightful exploring of advanced nanocarriers for the topical/transdermal treatment of skin diseases

Dermatological products constitute a big segment of the pharmaceutical market. From conventional products to more advanced ones, a wide variety of dosage forms have been developed till current date. A representative of the advanced delivery means is carrier-based systems, which can load large number of drugs for treatment of dermatological diseases, or simply for cosmeceutical purposes. To make them more favorable for topical delivery, further incorporation of these carriers in a topical vehicle, such as gels or creams is made. Therefore in this review article, an overview is compiled of the most commonly encountered novel carrier based topical delivery systems; namely lipid based (nanoemulsions, microemulsions, solid lipid nanoparticles [SLNs] and nanostructured lipid carriers [NLCs]), and vesicular carriers (non-deformable, such as liposomes, niosomes, emulsomes and cerosomes, and deformable, such as transfersomes, ethosomes, transethosomes, and penetration enhancer vesicles), with special emphasis on those loaded in a secondary gel vehicle. A special focus was made on the commonly encountered dermatological diseases, such as bacterial and fungal infections, psoriasis, dermatitis, eczema, vitiligo, oxidative damage, aging, alopecia, and skin cancer.

Lipid Cubic Systems for Sustained and Controlled Delivery of Antihistamine Drugs

Antihistamines are capable of blocking mediator responses in allergic reactions including allergic rhinitis and dermatological reactions. By incorporating various H1 receptor antagonists into a lipid cubic phase network, these active ingredients can be delivered locally over an extended period of time owing to the mucoadhesive nature of the system. Local delivery can avoid inducing unwanted side effects, often observed after systematic delivery. Lipid-based antihistamine delivery systems are shown here to exhibit prolonged release capabilities. In vitro drug dissolution studies investigated the extent and release rate of two model first-generation and two model second-generation H1 antagonist antihistamine drugs from two monoacyglycerol-derived lipid models. To optimize the formulation approach, the systems were characterized macroscopically and microscopically by small-angle X-ray scattering and polarized light to ascertain the mesophase accessed upon an incorporation of antihistamines of varying solubilities and size. The impact of encapsulating the antihistamine molecules on the degree of mucoadhesivity of the lipid cubic systems was investigated using multiparametric surface plasmon resonance. With the ultimate goal of developing therapies for the treatment of allergic reactions, the ability of the formulations to inhibit mediator release utilizing RBL-2H3 mast cells with the propensity to release histamine upon induction was explored, demonstrating no interference from the lipid excipient on the effectiveness of the antihistamine molecules.

Tailoring of Retinyl Palmitate-Based Ethosomal Hydrogel as a Novel Nanoplatform for Acne Vulgaris Management: Fabrication, Optimization, and Clinical Evaluation Employing a Split-Face Comparative Study

AIM

Retinyl palmitate (RP), the most stable vitamin A derivative, is used to treat photoaging and other skin disorders. The need to minimize the adverse effects of topical drug administration has led to an enhanced interest in loading RP on ethosomes for topical drug delivery. The aim of the current study was to prepare and compare the performance of RP decorated ethosomal hydrogel with tretinoin cream in the treatment of acne vulgaris as an approach to improve drug efficacy and decrease its side effects.

METHODS

RP-loaded ethosomes were prepared using the injection sonication technique. A Box-Behnken design using Design Expert® software was used for the optimization of formulation variables. Particle size, zeta potential (ZP), entrapment efficiency percent (EE%), % drug release, and permeation over 24 h of different formulations were determined. The optimal formulation was incorporated into a hydrogel. Finally, the efficacy and tolerability of the optimized RP ethosomal hydrogel were clinically evaluated for acne treatment using a split-face comparative clinical study.

RESULTS

The optimized ethosomal RP showed particle size of 195.8±5.45 nm, ZP of -62.1±2.85 mV, EE% of 92.63±4.33%, drug release % of 96.63±6.81%, and drug permeation % of 85.98 ±4.79%. Both the optimized RP ethosomal hydrogel and tretinoin effectively reduced all types of acne lesions (inflammatory, non-inflammatory, and total lesions). However, RP resulted in significantly lower non-inflammatory and total acne lesion count than the marketed tretinoin formulation. Besides, RP-loaded ethosomes showed significantly improved tolerability compared to marketed tretinoin with no or minimal skin irritation symptoms.

CONCLUSION

RP ethosomal hydrogel is considerably effective in controlling acne vulgaris with excellent skin tolerability. Therefore, it represents an interesting alternative to conventional marketed tretinoin formulation for topical acne treatment.

Intranasal In Situ Gel of Apixaban-Loaded Nanoethosomes: Preparation, Optimization, and In Vivo Evaluation

The present study was conducted to formulate ethosomal thermoreversible in situ gel of apixaban, an anticoagulant drug, for nasal delivery. Ethosomes were formed, of lecithin, cholesterol, and ethanol, by using thin-film hydration method. The prepared ethosomes were characterized by Zetasizer, transmission electron microscope, entrapment efficiency, and in vitro study. The selected ethosomal formula (API-ETHO2) was incorporated in gel using P407 and P188 as thermoreversible agents and carbopol 934 as mucoadhesive agent. Box-Behnken design was used to study the effect of independent variables (concentration of P407, P188, and carbopol 934) on gelation temperature, mucoadhesive strength, and in vitro cumulative percent drug released at 12h (response variables). The optimized formulation was subjected to compatibility study, ex vivo permeation, histopathological examination for the nasal mucosa, and in vivo study. API-ETHO2 was spherical with an average size of 145.1±12.3 nm, zeta potential of -20±4 mV, entrapment efficiency of 67.11%±3.26, and in vitro % release of 79.54%±4.1. All gel formulations exhibited an acceptable pH and drug content. The optimum gel offered 32.3°C, 1226.3 dyne/cm², and 53.50% for gelation temperature, mucoadhesive strength, and in vitro percent released, respectively. Apixaban ethosomal in situ gel evolved higher ex vivo permeation (1.499±0.11 μg/cm²h) through the nasal mucosa than pure apixaban gel. Histopathological study assured that there is no necrosis or tearing of the nasal mucosa happened by ethosomal gel. The pharmacokinetic parameters in rabbit plasma showed that intranasal administration of optimized API-ethosomal in situ gel achieved higher C_max and AUC_0-∞ than unprocessed API nasal gel, nasal suspension, and oral suspension. The ethosomal thermoreversible nasal gel established its potential to improve nasal permeation and prolong anticoagulant effect of apixaban.

Nanovesicle Formulation Enhances Anti-inflammatory Property and Safe Use of Piroxicam

BACKGROUND

Enhanced utilization of certain drugs may be possible through the development of alternative delivery forms. It has been observed that NSAIDs have adverse gastrointestinal tract effects such as irritation and ulceration during anti-inflammatory therapy. This challenge may be overcome through nano topical formulations.

OBJECTIVE

This study aimed to explore the potentials of a transdermal nanovesicular formulation for safe and enhanced delivery of piroxicam (PRX), a poorly water-soluble NSAID.

METHODS

Preformulation studies were conducted using DSC and FTIR. Ethosomal nanovesicular carrier (ENVC) was prepared by thin-film deposition technique using Phospholipon® 90 H (P90H) and ethanol and then converted into gel form. The formulation was characterized using a commercial PRX gel as control. Permeation studies were conducted using rat skin and Franz diffusion cell. Samples were assayed spectrophotometrically, and the obtained data was analyzed by ANOVA using GraphPad Prism software.

RESULTS

The preformulation studies showed compatibility between PRX and P90H. Spherical vesicles of mean size 343.1 ± 5.9 nm, and polydispersity index 0.510 were produced, which remained stable for over 2 years. The optimized formulation (PE30) exhibited pseudoplastic flow, indicating good consistency. The rate of permeation increased with time in the following order: PE30 > Commercial, with significant difference (p< 0.05). It also showed higher inhibition of inflammation (71.92 ± 9.67%) than the reference (64.12 ± 7.92%).

CONCLUSION

ENVC gel of PRX was formulated. It showed potentials for enhanced transdermal delivery and anti-inflammatory activity relative to the reference. This may be further developed as a safe alternative to the oral form.

Atopic Dermatitis as a Multifactorial Skin Disorder. Can the Analysis of Pathophysiological Targets Represent the Winning Therapeutic Strategy?

Atopic dermatitis (AD) is a pathological skin condition with complex aetiological mechanisms that are difficult to fully understand. Scientific evidence suggests that of all the causes, the impairment of the skin barrier and cutaneous dysbiosis together with immunological dysfunction can be considered as the two main factors involved in this pathological skin condition. The loss of the skin barrier function is often linked to dysbiosis and immunological dysfunction, with an imbalance in the ratio between the pathogen Staphylococcus aureus and/or other microorganisms residing in the skin. The bibliographic research was conducted on PubMed, using the following keywords: 'atopic dermatitis', 'bacterial therapy', 'drug delivery system' and 'alternative therapy'. The main studies concerning microbial therapy, such as the use of bacteria and/or part thereof with microbiota transplantation, and drug delivery systems to recover skin barrier function have been summarized. The studies examined show great potential in the development of effective therapeutic strategies for AD and AD-like symptoms. Despite this promise, however, future investigative efforts should focus both on the replication of some of these studies on a larger scale, with clinical and demographic characteristics that reflect the general AD population, and on the process of standardisation, in order to produce reliable data.

Antihistamines in children and adolescents: A practical update

Histamine is a chemical mediator, released predominantly by tissue mast cells, circulating basophils, and neurons, which are activated in response to various immunological and non-immunological stimuli. Histamine has to bind to specific receptors to exert its physiological and pathophysiological functions. Endogenous histamine is the main mediator of the immediate allergic response, which moreover, performs other multiple functions, including regulation of gastric secretion, neurotransmission in the central nervous system, and immunomodulatory activity. The involvement of histamine in various disorders and the importance of receptors in the clinical features have relevant implications in clinical practice. Anti-H1 antihistamines contrast the histamine-dependent effects, mainly concerning nasal symptoms and cutaneous itching and wheal. Antihistamines are among the most prescribed drugs in pediatric care. This review updates the practical use of antihistamines in children and adolescents.

Phospholipid Vesicles for Dermal/Transdermal and Nasal Administration of Active Molecules: The Effect of Surfactants and Alcohols on the Fluidity of Their Lipid Bilayers and Penetration Enhancement Properties

This is a comprehensive review on the use of phospholipid nanovesicles for dermal/transdermal and nasal drug administration. Phospholipid-based vesicular carriers have been widely investigated for enhanced drug delivery via dermal/transdermal routes. Classic phospholipid vesicles, liposomes, do not penetrate the deep layers of the skin, but remain confined to the upper stratum corneum. The literature describes several approaches with the aim of altering the properties of these vesicles to improve their penetration properties. Transfersomes and ethosomes are the most investigated penetration-enhancing phospholipid nanovesicles, obtained by the incorporation of surfactant edge activators and high concentrations of ethanol, respectively. These two types of vesicles differ in terms of their structure, characteristics, mechanism of action and mode of application on the skin. Edge activators contribute to the deformability and elasticity of transfersomes, enabling them to penetrate through pores much smaller than their own size. The ethanol high concentration in ethosomes generates a soft vesicle by fluidizing the phospholipid bilayers, allowing the vesicle to penetrate deeper into the skin. Glycerosomes and transethosomes, phospholipid vesicles containing glycerol or a mixture of ethanol and edge activators, respectively, are also covered. This review discusses the effects of edge activators, ethanol and glycerol on the phospholipid vesicle, emphasizing the differences between a soft and an elastic nanovesicle, and presents their different preparation methods. To date, these differences have not been comparatively discussed. The review presents a large number of active molecules incorporated in these carriers and investigated in vitro, in vivo or in clinical human tests.

Mechanism investigation of ethosomes transdermal permeation

Ethosomes are widely used to promote transdermal permeation of both lipophilic and hydrophilic drugs, but the mechanism of interaction between the ethosomes and the skin remains unclear. In this work, it was exploded with several technologies and facilities. Firstly, physical techniques such as attenuated total reflectance fourier-transform infrared and laser confocal Raman were used and the results indicated that the phospholipids configuration of stratum corneum changes from steady state to unstable state with the treatment of ethosomes. Differential scanning calorimetry reflected the thermodynamics change in stratum corneum after treatment with ethosomes. The results revealed that the skin of Bama mini-pigs, which is similar to human skin, treated by ethosomes had a relatively low T_m and enthalpy. Scanning electron microscopy and transmission electron microscopy showed that the microstructure and ultrastructure of stratum corneum was not damaged by ethosomes treatment. Furthermore, confocal laser scanning microscopy revealed that lipid labeled ethosomes could penetrate the skin via stratum corneum mainly through intercellular route, while during the process of penetration, phospholipids were retained in the upper epidermis. Cell experiments confirmed that ethosomes were distributed mainly on the cell membrane. Further study showed that only the drug-loaded ethosomes increased the amount of permeated drug. The current study, for the first time, elucidated the mechanistic behavior of ethosomes in transdermal application from molecular configuration, thermodynamic properties, ultrastructure, fluorescent labeling and cellular study. It is anticipated that the approaches and results described in the present study will benefit for better design of drug-loaded ethosomes.

Factorial design based curcumin ethosomal nanocarriers for the skin cancer delivery: in vitro evaluation

Melanoma is the most deadly and life-threatening form of skin cancer with progressively higher rates of incidence worldwide. The objective of the present investigation is to develop and to statistically optimize and characterize curcumin (CUR) loaded ethosomes for treatment of melanoma. A two factor, three level (3²) factorial design approach was employed for the optimization of ethosomes. The prepared ethosomes were evaluated for size, zeta potential, entrapment efficiency, in vitro skin permeation and deposition ability. The optimized ethosomal formulation was evaluated for in vitro cytotoxicity and cellular uptake studies using A375 human melanoma cells. The optimized formulation has imperfect round shaped unilamellar structures with a mean vesicle size of 247 ± 5.25 nm and an entrapment efficiency of 92.24 ± 0.20%. The in vitro skin permeation studies proved the superiority of ethosomes over the traditional liposomes in terms of the amount of drug permeated and deposited in skin layers. Fluorescence microscopy showed the enhanced penetration of ethosomes into the deeper layers of the skin. In vitro cytotoxicity and cellular uptake studies revealed that curcumin ethosomes have significantly improved cytotoxicity and cellular uptake in A375 human melanoma cell lines. The colony formation assay results showed that curcumin ethosomes have a superior antiproliferative effect as they effectively inhibit the clonogenic ability of A375 cells. The flow cytometry results indicate that curcumin ethosomes induce cell death in A375 cells by apoptosis mechanism. The present study provides a strong rationale and motivation for further investigation of newly developed curcumin ethosomes as a potential therapeutic strategy for melanoma treatment.

Transdermal ethosomal gel nanocarriers; a promising strategy for enhancement of anti-hypertensive effect of carvedilol

The current study was conducted to develop vesicular ethosomal gel (ethogel) systems for upgrading the transdermal delivery of anti-hypertensive carvedilol. Ethosomes composed of Phospholipon 100 H, cholesterol, ethanol, and Transcutol P at different ratios, were prepared by thin-film hydration method with sonication. Carvedilol-loaded ethosomes were characterized by microscopic examinations followed by other in-vitro assessments. Selected ethosomal formulation (E10) was incorporated into different concentrations of gelling agents to prepare the ethogel formulations. Ethogels were subjected to physicochemical characterization, compatibility, and in-vitro drug release studies. Ex-vivo skin permeation and retention studies were performed followed by in-vivo studies in induced hypertensive rats. The smooth ethosomes demonstrated vesicular size of 201.55-398.55 nm, entrapment efficiency of 30.00-90.66% and loading capacity of 7.64-43.04% with zeta potential range of -30.30 to -44.90 mV. The homogeneous ethogels exhibited appropriate results of pH and drug content measurements. Spreadability was observed as a function of viscosity as the latter increased, the former decreased. The ethogel formulation (G2) manifested satisfactory physical appearance, spreadability, viscosity, and in-vitro release. In comparison to pure carvedilol gel, tested formulations (E10 and G2) developed high ex-vivo permeation, steady-state flux and drug retention through skin layers. The in-vivo study of G2 formulation revealed a significant gradual decline (p < 0.01) in the mean arterial pressure of rats at the second hour of experiment (146.11 mmHg) with continuous significant decrease (p < 0.001) after 6 h (98.88 mmHg). In conclusion, ethogels as promising lipid carriers proved their potential to enhance skin permeation with extended anti-hypertensive action of carvedilol.

Transdermal applications of ethosomes - a detailed review

Skin, the largest organ of the body serves as a potential route of drug delivery for local and systemic effects. However, the outermost layer of skin, the stratum corneum (SC) acts as a tough barrier that prevents penetration of hydrophilic and high molecular weight drugs. Ethosomes are a novel phospholipid vesicular carrier containing high ethanol concentrations and offer improved skin permeability and efficient bioavailability due to their structure and composition. This article gives a review of ethosomes including their compositions, types, mechanism of drug delivery, stability, and safety behaviour. This article also provides a detailed overview of drug delivery applications of ethosomes in various diseases.

Ethosomal nanocarriers: the impact of constituents and formulation techniques on ethosomal properties, in vivo studies, and clinical trials

Ethosomal systems are novel lipid vesicular carriers containing a relatively high percentage of ethanol. These nanocarriers are especially designed for the efficient delivery of therapeutic agents with different physicochemical properties into deep skin layers and across the skin. Ethosomes have undergone extensive research since they were invented in 1996; new compounds were added to their initial formula, which led to the production of new types of ethosomal systems. Different preparation techniques are used in the preparation of these novel carriers. For ease of application and stability, ethosomal dispersions are incorporated into gels, patches, and creams. Highly diverse in vivo models are used to evaluate their efficacy in dermal/transdermal delivery, in addition to clinical trials. This article provides a detailed review of the ethosomal systems and categorizes them on the basis of their constituents to classical ethosomes, binary ethosomes, and transethosomes. The differences among these systems are discussed from several perspectives, including the formulation, size, ζ-potential (zeta potential), entrapment efficiency, skin-permeation properties, and stability. This paper gives a detailed review on the effects of ethosomal system constituents, preparation methods, and their significant roles in determining the final properties of these nanocarriers. Furthermore, the novel pharmaceutical dosage forms of ethosomal gels, patches, and creams are highlighted. The article also provides detailed information regarding the in vivo studies and clinical trials conducted for the evaluation of these vesicular systems.

Development, characterization, and skin delivery studies of related ultradeformable vesicles: transfersomes, ethosomes, and transethosomes

Ultradeformable vesicles (UDV) have recently become a promising tool for the development of improved and innovative dermal and transdermal therapies. The aim of this work was to study three related UDV: transfersomes, ethosomes, and transethosomes for the incorporation of actives of distinct polarities, namely, vitamin E and caffeine, and to evaluate the effect of the carrier on skin permeation and penetration. These actives were incorporated in UDV formulations further characterized for vesicles imaging by transmission electron microscopy; mean vesicle size and polydispersity index by photon correlation spectroscopy; zeta potential by laser-Doppler anemometry; deformability by pressure-driven transport; and incorporation efficiency (IE) after actives quantification by high-performance liquid chromatography. Topical delivery studies were performed in order to compare UDV formulations regarding the release, skin permeation, and penetration profiles. All UDV formulations showed size values within the expected range, except transethosomes prepared by “transfersomal method”, for which size was smaller than 100 nm in contrast to that obtained for vesicles prepared by “ethosomal method”. Zeta potential was negative and higher for formulations containing sodium cholate. The IE was much higher for vitamin E- than caffeine-loaded UDV as expected. For flux measurements, the following order was obtained: transethosomes (TE) > ethosomes (E) ≥ transfersomes (T). This result was consistent with the release and skin penetration profiles for Vitamin E-loaded UDV. However, the releasing results were totally the opposite for caffeine-loaded UDV, which might be explained by the solubility and thermodynamic activity of this active in each formulation instead of the UDV deformability attending to the higher non-incorporated fraction of caffeine. Anyway, a high skin penetration and permeation for all caffeine-loaded UDV were obtained. Transethosomes were more deformable than ethosomes and transfersomes due to the presence of both ethanol and surfactant in their composition. All these UDV were suitable for a deeper skin penetration, especially transethosomes.

Nano vesicular lipid carriers of angiotensin II receptor blocker: Anti-hypertensive and skin toxicity study in focus

OBJECTIVE

Nanoethosomal carriers of valsartan have been previously prepared, characterized and optimized. A gel formulation of valsartan vesicular lipid carriers was composed of Carbopol(®) (1% w/w), polyethylene glycol-400 (15% w/w) and triethanolamine (0.5% w/w). The influence of the valsartan nanoethosomal formulation developed on the blood pressure of experimental hypertensive rats, and its potential for skin irritation, are presented in this report.

MATERIALS AND METHODS

The experimental rats were divided into three groups; the control group received no treatment (Group A). Group B was administered methyl prednisolone acetate (20 mg/kg/week) for two weeks (hypertensive control). Group C received methyl prednisolone acetate, followed by administration of the valsartan ethosomal formulation. The blood pressure of the rats was measured using a non-invasive rat blood pressure instrument based on the tail-cuff technique. The statistical analysis was performed using GraphPad InStat 3 software.

RESULTS AND DISCUSSION

The treatment group showed a significant (P < 0.05) and constant fall in blood pressure, for up to 48 h. The valsartan ethosomal formulation was found to be effective, with a 34.11% reduction in blood pressure. The formulation's potential for skin irritation was assessed by the Draize irritation score test, which ruled out the possibility of any skin irritation caused by application of the formulation in rats.

CONCLUSION

Our results suggest that nanoethosomes are efficient carriers for transdermal delivery of valsartan, for the management of hypertension.