Vesicles as a tool for transdermal and dermal delivery

Advanced application of nanotechnology in active constituents of Traditional Chinese Medicines

Traditional Chinese Medicines (TCMs) have been used for centuries for the treatment and management of various diseases. However, their effective delivery to targeted sites may be a major challenge due to their poor water solubility, low bioavailability, and potential toxicity. Nanocarriers, such as liposomes, polymeric nanoparticles, inorganic nanoparticles and organic/inorganic nanohybrids based on active constituents from TCMs have been extensively studied as a promising strategy to improve the delivery of active constituents from TCMs to achieve a higher therapeutic effect with fewer side effects compared to conventional formulations. This review summarizes the recent advances in nanocarrier-based delivery systems for various types of active constituents of TCMs, including terpenoids, polyphenols, alkaloids, flavonoids, and quinones, from different natural sources. This review covers the design and preparation of nanocarriers, their characterization, and in vitro/vivo evaluations. Additionally, this review highlights the challenges and opportunities in the field and suggests future directions for research. Nanocarrier-based delivery systems have shown great potential in improving the therapeutic efficacy of TCMs, and this review may serve as a comprehensive resource to researchers in this field.

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.

New Insights in Topical Drug Delivery for Skin Disorders: From a Nanotechnological Perspective

Skin, the largest organ in humans, is an efficient route for the delivery of drugs as it circumvents several disadvantages of the oral and parenteral routes. These advantages of skin have fascinated researchers in recent decades. Drug delivery via a topical route includes moving the drug from a topical product to a locally targeted region with dermal circulation throughout the body and deeper tissues. Still, due to the skin's barrier function, delivery through the skin can be difficult. Drug delivery to the skin using conventional formulations with micronized active components, for instance, lotions, gels, ointments, and creams, results in poor penetration. The use of nanoparticulate carriers is one of the promising strategies, as it provides efficient delivery of drugs through the skin and overcomes the disadvantage of traditional formulations. Nanoformulations with smaller particle sizes contribute to improved permeability of therapeutic agents, targeting, stability, and retention, making nanoformulations ideal for drug delivery through a topical route. Achieving sustained release and preserving a localized effect utilizing nanocarriers can result in the effective treatment of numerous infections or skin disorders. This article aims to evaluate and discuss the most recent developments of nanocarriers as therapeutic agent vehicles for skin conditions with patent technology and a market overview that will give future directions for research. As topical drug delivery systems have shown great preclinical results for skin problems, for future research directions, we anticipate including in-depth studies of nanocarrier behavior in various customized treatments to take into account the phenotypic variability of the disease.

An overview of topical lipid-based and polymer-based nanocarriers for treatment of psoriasis

Psoriasis is a consistently recurring, inflammatory skin disease, affecting about 2 - 5 % of the world population. Different types of psoriasis can be observed such as guttate psoriasis, pustular psoriasis, psoriatic arthritis, scalp psoriasis, flexural psoriasis etc. Several therapeutic approaches are available for the treatment of psoriasis. However, none of them are entirely safe and effective to treat the disease without compromising patient compliance. The traditional treatment plan is associated with harmful side effects such asimmune system suppression and damage of essential organs at high doses, which poses a challenge to treat psoriasis. Novel drug delivery systems are being developed to replace traditional therapy in order to address these shortcomings. Currently, nanoformulations have gained widespread application for treatment of psoriasis. Researchers have developed different types of lipid-based nanoparticles like liposomes, niosomes, ethosomes, transethosomes, nanostructured lipid carriers and solid lipid nanoparticles. These innovative formulations provide advantages in terms of reduction in dose, dosing frequency, dose-dependency with enhanced efficacy, improved encapsulation efficiency, controlled release, increased surface area, high bioavailability and greater stratum corneum permeability. This review highlights detailed and comparative discussion of lipid-based and polymer-based nanoparticles for psoriasis along with the pathophysiology and other treatments of psoriasis.

The Impact of Flavonoid-Loaded Nanoparticles in the UV Protection and Safety Profile of Topical Sunscreens

Excessive UV radiation exposure is harmful to skin cells since sunburn is accompanied by oxidative burst, leading to a rapid increase in skin cancer. However, the insufficient UV photoprotection of approved sunscreens and the negative impact of their compositions on ecosystems and human health makes the utility of sunscreen a questionable recommendation. Therefore, discovering UV filters with significant antioxidant activity and improved topical performance and photostability is an urgent need. Recently, the use of nanosized natural molecules incorporated in sunscreens has been a scientific hot topic, as it has been suggested that they provide a synergistic effect with synthetic UV filters, improving overall SPF and antioxidant activity, higher retention on the epidermis, and less toxicity. The aim of this review was to verify the usefulness of sunscreens incorporating flavonoid-loaded nanoparticles. A literature review was performed, where original and review articles published in the last 6 years were analyzed. Formulations containing nanosized flavonoids with improved UVA photoprotection and safer toxicological profiles, associated or not with synthetic filters, are promising sunscreens and more clinical investigation must be performed to validate these findings.

The novel treatments based on tissue engineering, cell therapy and nanotechnology for cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a global public health issue. Conventional treatments have substantial costs, side effects, and parasite resistance. Due to easy application and inexpensive cost, topical treatment is the optimal approach for CL. It could be used alone or with systemic treatments. Electrospun fibers as drug release systems in treating skin lesions have various advantages such as adjustable drug release rate, maintaining appropriate humidity and temperature, gas exchange, plasticity at the lesion site, similarity with the skin extracellular matrix (ECM) and drug delivery with high efficiency. Hydrogels are valuable scaffolds in the treatment of skin lesions. The important features of hydrogels include preserving unstable drugs from degradation, absorption of wound secretions, high biocompatibility, improving the re-epithelialization of the wound and preventing the formation of scars. One of the issues in local drug delivery systems for the skin is the low permeability of drugs in the skin. Polymeric scaffolds that are designed as microneedle patches can penetrate the skin and overcome this challenge. Also, drug delivery using nanocarriers increases the effectiveness of drugs in lower and more tolerable doses and reduces the toxicity of drugs. The application of cell therapy in the treatment of parasitic and infectious diseases has been widely investigated. The complexity of leishmaniasis treatment requires identifying new treatment options like cell therapy to overcome the disease. Topics investigated in this study include drug delivery systems based on tissue engineering scaffolds, nanotechnology and cell therapy-based studies to reduce the complications of CL.

On the deformability of additivated phosphatidylcholine liposomes: Molecular dynamic regimes and membrane elasticity

Liposomes with enhanced elasticity have been proven to increase the efficiency of drug transport across the skin. The understanding of the background physicochemical processes driving the liposome viscoelastic properties is an essential feature for the design of effective formulations involving different lipids and additive molecules. In this work we use field-cycled nuclear magnetic resonance relaxometry to analyze both the mechanical properties of liposome membranes, and their relationship with the involved molecular dynamics. Different liposomal formulations were considered. We show a correlation between the molecular dynamical regime and mesoscopic physical parameters that define the expected deformability of the vesicles. Results strongly suggest that the purity of the used lipids may influence the elastic properties of the membranes in an appreciable way. Common features in the behaviour of the involved dynamic variables were identified by comparing formulations with surfactants of similar molecular weight.

Tailoring of Novel Bile Salt Stabilized Vesicles for Enhanced Transdermal Delivery of Simvastatin: A New Therapeutic Approach against Inflammation

Simvastatin (SMV), a cholesterol-lowering agent, has antioxidant and anti-inflammatory effects. Nevertheless, the oral use of SMV is linked with poor systemic bioavailability owing to its limited aqueous solubility and extensive first-pass metabolism. The aim of this study was to evaluate the feasibility of transdermal delivery of SMV using bile salt stabilized vesicles (bilosomes) for enhancing the anti-inflammatory potential of SMV. SMV-loaded bilosomes (SMV-BS) were prepared by the thin film hydration technique and optimized by 3³ Box-Behnken design. The fabricated SMV-BS were assessed for vesicle size, entrapment efficiency (% EE) and cumulative drug release. The optimized formula was incorporated into HPMC gel and investigated for physical properties, ex vivo permeation, in vivo pharmacokinetic study and anti-inflammatory potential in inflamed paw edema rat model. The optimized SMV-BS showed vesicle size of 172.1 ± 8.1 nm and % EE of 89.2 ± 1.8%. In addition, encapsulating SMV within bilosomal vesicles remarkably sustained drug release over 12 h, compared to plain drug suspension. Furthermore, SMV-loaded bilosomal gel showed a three-fold enhancement in SMV transdermal flux, compared to plain drug suspension. Most importantly, the relative bioavailability of SMV-BS gel was ~2-fold and ~3-fold higher than those of oral SMV suspension and SMV gel, respectively. In carrageenan-induced paw edema model, SMV-BS gel induced a potent anti-inflammatory effect, as evidenced by a remarkable reduction in paw edema, which was comparable to that of the standard anti-inflammatory drug, indomethacin. Collectively, bilosomes might represent a plausible transdermal drug delivery system that could enhance the anti-inflammatory activity of SMV by boosting its skin permeation and its systemic bioavailability.

Epidermis-on-a-chip system to develop skin barrier and melanin mimicking model

In vitro skin models are rapidly developing and have been widely used in various fields as an alternative to traditional animal experiments. However, most traditional static skin models are constructed on Transwell plates without a dynamic three-dimensional (3D) culture microenvironment. Compared with native human and animal skin, such in vitro skin models are not completely biomimetic, especially regarding their thickness and permeability. Therefore, there is an urgent need to develop an automated biomimetic human microphysiological system (MPS), which can be used to construct in vitro skin models and improve bionic performance. In this work, we describe the development of a triple-well microfluidic-based epidermis-on-a-chip (EoC) system, possessing epidermis barrier and melanin-mimicking functions, as well as being semi-solid specimen friendly. The special design of our EoC system allows pasty and semi-solid substances to be effectively utilized in testing, as well as allowing for long-term culturing and imaging. The epidermis in this EoC system is well-differentiated, including basal, spinous, granular, and cornified layers with appropriate epidermis marker (e.g. keratin-10, keratin-14, involucrin, loricrin, and filaggrin) expression levels in corresponding layers. We further demonstrate that this organotypic chip can prevent permeation of over 99.83% of cascade blue (a 607 Da fluorescent molecule), and prednisone acetate (PA) was applied to test percutaneous penetration in the EoC. Finally, we tested the whitening effect of a cosmetic on the proposed EoC, thus demonstrating its efficacy. In summary, we developed a biomimetic EoC system for epidermis recreation, which could potentially serve as a useful tool for skin irritation, permeability, cosmetic evaluation, and drug safety tests.

Development of skin-permeable flexible liposome using ergosterol esters containing unsaturated fatty acids

Ergosterol (Ergo) and cholesterol contribute to performances of liposomes by increasing membrane packing density and physical stability. However, as these sterols can reduce membrane flexibility, they can lower skin permeability of liposomes. We synthesized ergosterol ester (Ergo-Est) containing unsaturated fatty acid different from Ergo in size and physical properties. In this work, we investigated effects of Ergo-Est and Ergo on physical properties of liposomes. We incorporated Ergo, Ergo-oleate (EO^18:1), Ergo-linoleate (EL^18:2), and Ergo-linolenate (ELn^18:3) into the liposomal membrane of egg phosphatidylcholine and soybean lecithin. Ergo-Est did not reduce membrane fluidity as much as Ergo. Nevertheless, Ergo-Est increased membrane packing density and physical stability of liposomes. EL^18:2 and ELn^18:3 almost maintained membrane flexibility and skin permeability of liposomes, while Ergo significantly reduced them. Skin permeation test demonstrated that EL^18:2 and ELn^18:3 liposomes permeated to the dermis, whereas Ergo liposome mostly remained in the stratum corneum. This is the first report to show that EL^18:2 and ELn^18:3 can be efficient sterol compounds for flexible liposome formulation.

Localized topical drug delivery systems for skin cancer: Current approaches and future prospects

Topical drug delivery presents a novel substitute to the conventional drug-distribution routes of oral delivery and injection. Apart from the simplicity and non-invasiveness, the skin also serves as a “reservoir” that sustains administration over a period of days. Nanocarriers provide new potential for the treatment of skin disease. The skin’s barrier function offers a considerable obstacle for the potential nanocarriers to infiltrate into the tissue. However, the barrier is partially weakened in case of damage or inflammation, as in the case of skin cancer. Nanoparticles may promote the penetration of the skin. Extensive research has been done into producing nanoparticles for topical distribution; nevertheless, relatively little progress has been achieved in transferring them to the clinic for treating skin malignancies. The prior art features the critical concepts of skin malignancies and techniques in current clinical care. The present review gives a complete viewpoint of the numerous nanoparticle technologies studied for the topical treatment of skin malignancies and outlines the hurdles that hamper its advancement from the bench to the bedside. The review also intends to give knowledge of the routes that control nanoparticle penetration into the skin and their interactions inside the tissue.

Novel Bile Salt Stabilized Vesicles-Mediated Effective Topical Delivery of Diclofenac Sodium: A New Therapeutic Approach for Pain and Inflammation

The oral delivery of diclofenac sodium (DNa), a non-steroidal analgesic, anti-inflammatory drug, is associated with various gastrointestinal side effects. The aim of the research was to appraise the potential of transdermal delivery of DNa using bilosomes as a vesicular carrier (BSVC) in inflamed paw edema. DNa-BSVCs were elaborated using a thin-film hydration technique and optimized using a 3¹.2² multilevel categoric design with Design Expert^® software 10 software (Stat-Ease, Inc., Minneapolis, MI, USA). The effect of formulation variables on the physicochemical properties of BSVC, as well as the optimal formulation selection, was investigated. The BSVCs were evaluated for various parameters including entrapment efficiency (EE%), vesicle size (VS), zeta potential (ZP) and permeation studies. The optimized BSVC was characterized for in vitro release, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and incorporated into hydrogel base. The optimized DNa-BSVC gel effectiveness was assessed in vivo using carrageenan-induced paw edema animal model via cyclooxygenase 2 (COX-2), interleukin 6 (IL-6), Hemooxygenase 1 (HO-1) and nuclear factor-erythroid factor2-related factor 2 (Nfr-2) that potentiate anti-inflammatory and anti-oxidant activity coupled with histopathological investigation. The resulting vesicles presented VS from 120.4 ± 0.65 to 780.4 ± 0.99 nm, EE% from 61.7 ± 3.44 to 93.2 ± 2.21%, ZP from −23.8 ± 2.65 to −82.1 ± 12.63 mV and permeation from 582.9 ± 32.14 to 1350.2 ± 45.41 µg/cm². The optimized BSVCs were nano-scaled spherical vesicles with non-overlapped bands of their constituents in the FTIR. Optimized formulation has superior skin permeability ex vivo approximately 2.5 times greater than DNa solution. Furthermore, histological investigation discovered that the formed BSVC had no skin irritating properties. It was found that DNa-BSVC gel suppressed changes in oxidative inflammatory mediators (COX-2), IL-6 and consequently enhanced Nrf2 and HO-1 levels. Moreover, reduction of percent of paw edema by about three-folds confirmed histopathological alterations. The results revealed that the optimized DNa-BSVC could be a promising transdermal drug delivery system to boost anti-inflammatory efficacy of DNa by enhancing the skin permeation of DNa and suppressing the inflammation of rat paw edema.

Spanlastics gel-A novel drug carrier for transdermal delivery of glimepiride

Glimepiride (3rd-generation sulfonylurea) is used for treatment of type 2 diabetes, but its oral administration has been associated with severe gastric disturbances such as nausea, vomiting, heartburn, anorexia, haemolytic anaemia. Accordingly, the transdermal route may represent a potentially suitable alternative. This work investigates the usefulness of a novel drug carrier system for transdermal application. The system investigated were called spanlastics gels and constituted span 60 with edge activator (tween 60 or tween 80). Spanlastics gel has been introduced as a stable form alternative to the liquid formulations of spanlastics. Spanlastics gels were prepared by coacervation phase separation method. Entrapment efficiency and size of spanlastics vesicles produced from the hydration of spanlastics gels were characterised. In vitro release and skin permeation of glimepiride from various spanlastics gel formulations were investigated across mixed cellulose membrane and excised rabbit skin. The obtained results indicated that the maximum entrapment efficiency was 65.36% when the tween 60 content was 30%. The drug release and permeation were increase as the concentration of edge activator increased. Spanlastics gel prepared with Tween 80 at concentration 50% showed higher permeability and flux value (248.69 µg/cm²and 8.31 µg/cm².h, respectively) through rabbit skin.

Clove Oil Endorsed Transdermal Flux of Dronedarone Hydrochloride Loaded Bilosomal Nanogel: Factorial Design, In vitro Evaluation and Ex vivo Permeation

The goal of this study was to develop a bilosomal gel formulation to enhance transdermal permeability of dronedarone hyrdrochloride (DRN) which suffers from poor oral absorption and limited bioavailability. To overcome this obstacle, bilosomes were successfully prepared using 2³ full-factorial design. Span®40, cholesterol, sodium deoxycholate (bile salt), clove oil (permeability enhancer), and either Tween® 60 or Tween® 80 (edge activator) were used in bilosome preparation by ethanol injection method. In this design, independent variables were X1, edge activator type; X2, edge activator amount (mg); and X3, permeability enhancer concentration (% w/v). Optimal formula (B2) of the highest desirability of (0.776) demonstrated minimum vesicle size (VS) of 312.4 ± 24.42 nm, maximum absolute value of zeta potential (ZP) - 36.17 ± 2.57 mV, maximum entrapment efficiency (EE %) of 80.95 ± 3.01%, maximum deformability Index (DI) of 8.24 ± 1.26 g and maximum drug flux after 12 h (J₁₂) of 21.23 ± 1.54 µg/cm² h upon ex vivo permeation study. After 12 h, 70.29 ± 6.46% of DRN was released from B2. TEM identification of B2 showed spherical shaped nanosized vesicles which were physically stable for 3 months at different temperatures. B2 was incorporated into carboxymethylcellulose gel base for easiness of dermal application. B2 gel demonstrated good physical properties, non-Newtonian psuedoplastic flow, and enhanced release (57.0 ± 8.68% of DRN compared to only 13.3 ± 1.2% released from drug suspension after 12 h) and enhanced skin permeation.

Surface-Modified Bilosomes Nanogel Bearing a Natural Plant Alkaloid for Safe Management of Rheumatoid Arthritis Inflammation

Rheumatoid arthritis (RA) is a chronic inflammatory illness affecting the joints. The characteristic of RA is gradual joint deterioration. Current RA treatment alleviates signs such as inflammation and pain and substantially slows the progression of the disease. In this study, we aimed to boost the transdermal delivery of berberine (a natural product) by encapsulating it in chitosan, surface-modified bilosomes nanogel for better management of the inflammation of RA. The chitosan-coated bilosomes loaded with berberine (BER-CTS-BLS) were formulated according to the thin-film hydration approach and optimized for various causal variables, considering the effect of lipid, sodium deoxycholate, and chitosan concentrations on the size of the particles, entrapment, and the surface charge. The optimized BER-CTS-BLS has 202.3 nm mean diameter, 83.8% entrapment, and 30.8 mV surface charge. The optimized BER-CTS-BLS exhibited a delayed-release profile in vitro and increased skin permeability ex vivo. Additionally, histological examination revealed that the formulated BLS had no irritating effects on the skin. Furthermore, the optimized BER-CTS-BLS ability to reduce inflammation was evaluated in rats with carrageenan-induced paw edema. Our results demonstrate that the group treated with topical BER-CTS-BLS gel exhibited a dramatic reduction in rat paw edema swelling percentage to reach 24.4% after 12 h, which was substantially lower than other groups. Collectively, chitosan-coated bilosomes containing berberine have emerged as a promising therapeutic approach to control RA inflammation.

Recent Advances in Drug Design and Delivery Across Biological Barriers using Computational Models

Abstract:

The systemic delivery of pharmacological substances generally exhibits several significant limitations associated with the bio-distribution of active drugs in the body. As per consequence, human body’s defense mechanisms become impediments to drug delivery. Various technologies to overcome these limitations have been evolved including computational approaches and advanced drug delivery. As the body of human has evolved to defend itself from hostile biological as well as chemical invaders, along with that these biological barriers such as ocular barriers, blood-brain barriers, intestinal and skin barriers also limit the passage of drugs across desired sites. Therefore, efficient delivery remains an utmost challenge for researchers and scientists. The present review focuses on the techniques to deliver the drugs with efficient therapeutic efficacy at the targeted sites. This review article considered the insights into main biological barriers along with the application of computational or numerical methods dealing with different barriers by determining the drug flow, temperature and various other parameters. It also summarizes the advanced implantable drug delivery system to circumvent the inherent resistance showed by these biological barriers and in turn to improve the drug delivery.

Preparation and Evaluation of Polyvinylpyrrolidone Electrospun Nanofiber Patches of Pioglitazone for the Treatment of Atopic Dermatitis

Nanofibers have many promising biomedical applications. They can be used for designing transdermal and dermal drug delivery systems. This project aimed to prepare and characterize polyvinylpyrrolidone-based nanofibers as a dermal and transdermal drug delivery system using pioglitazone. Pioglitazone is an oral antidiabetic drug. In addition, it can act as an inflammatory process modulator, making it a good candidate for managing different skin inflammatory conditions such as atopic dermatitis, skin ulcers, and diabetic foot wound healing. Several nanofiber formulations were prepared using the electrospinning method at different drug loadings, polyvinylpyrrolidone concentrations, and flow rates. A cast film with the exact composition of selected nanofiber formulations was prepared as a control. Nanofibers were characterized using a scanning electron microscope to calculate the diameter. Fourier-transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and powder X-ray diffraction were performed for physical and biochemical characterizations. In vitro release, drug loading efficiency, and swelling studies were performed. Ex vivo permeation studies were performed using Franz diffusion cells with or without applying a solid microneedle roller. Round uniform nanofibers with a smooth surface were obtained. The diameter of nanofibers was affected by the drug loading and polymer concentration. Fourier-transform infrared spectra showed a potential physical interaction between the drug and the polymer. According to X-ray diffraction, pioglitazone existed in an amorphous form in prepared nanofibers, with partial crystallinity in the casted film. Nanofibers showed a higher swelling rate compared to the casted film. The drug dissolution rate for nanofibers was 2.3-folds higher than the casted films. The polymer concentration affected the drug dissolution rate for nanofibers; however, drug loading and flow rate did not affect the drug dissolution rate for nanofibers. The application of solid microneedles slightly enhances the total amount of drug permeation. However, it did not affect the flux of the drug through the separated epidermis layer for pioglitazone. The drug permeation flux in nanofibers was approximately five times higher than the flux of the casted film. It was observed that pioglitazone is highly retained in skin layers. Graphical abstract.

Efficacy of topical Miltefosine formulations in an experimental model of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a neglected tropical disease endemic in ~ 90 countries, with an increasing incidence. Presently available pharmacotherapy implies the systemic administration of moderately/very toxic drugs. Miltefosine (Milt) is the only FDA-approved drug to treat CL via the oral route (Impavido®). It produces side effects; in particular, teratogenic effects are of concern. A topical treatment would have the great advantage of minimising the systemic circulation of the drug, preventing side effects. We prepared dispersions containing Milt and liposomes of different compositions to enhance/modulate trans-epidermal penetration and evaluated in vitro and in vivo efficacy and toxicity, in vitro release rate of the drug and particles size stability with time. Treatments were topically administered to BALB/c mice infected with Leishmania (Leishmania) amazonensis. The dispersions containing 0.5% Milt eliminated 99% of the parasites and cured the lesions with a complete re-epithelisation, no visible scar and re-growth of hair. Fluid liposomes decreased the time to heal the lesion and the time needed to eliminate viable amastigotes from the lesion site. Relapse of the infection was not found 1 month after treatment in any case. Ultraflexible liposomes on the other hand had no significant in vitro effect but decreased in vivo efficacy. A topical Milt formulation including fluid liposomes seems a promising treatment against CL.

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.

Rationalizing the Design of Hyaluronic Acid-Decorated Liposomes for Targeting Epidermal Layers: A Combination of Molecular Dynamics and Experimental Evidence

This work provides information on the features of low molecular weight hyaluronic acid (HA)-decorated liposomes to target resveratrol (RSV) in the skin. Deformable liposomes were made of soy-phosphatidylcholine with Tween 80 as the fluidizing agent. For HA conjugation, three different phosphoethanolamines were tested: 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). The different phosphoethanolamine-HA conjugates were inserted into the liposome bilayer by hydration (HA on both faces of the bilayer) or by the postinsertion method (HA only on the external face of the bilayer). The effect of these variables on deformability was experimentally assessed by an in-house method (K value, the lower the value, the higher the deformability) and molecular dynamics (MD) simulations. The results showed that the K values of HA-liposomes obtained by hydration were higher than the K values of HA-liposomes prepared by postinsertion, and both were at least 10-fold higher than the K values of the corresponding plain liposomes. The nature of the lipid anchor played a key role in deformability (DMPE > DOPE > DPPE) with high variability in the case of DOPE formulations. These data were justified by the trends found in silico for the bilayer bending modulus and the HA end-to-end distance. In addition to liposome flexibility, the HA extent seems to be the key factor governing the skin penetration of RSV. When the extent is higher, the amount of the drug retained in the skin is larger. Regarding skin permeation, a parabolic trend was recorded, and the optimal amount to favor skin permeation was an approximately 30 HA/phospholipid (μg/mmol) ratio. This study reports the first piece of evidence that it is possible to control drug delivery in the skin by tuning the amount of HA on the vesicle surface.

Pharmaceutical nanocrystals: A promising approach for improved topical drug delivery

The barrier function of skin and non-optimal physicochemical properties of drug present a challenge to skin penetration of many drugs, thus motivating the development of novel drug delivery systems. Recently, nanocrystal-based formulations have been investigated for topical drug delivery and demonstrated improved skin penetration. This review highlights barriers in skin penetration, current techniques to improve topical delivery and application of nanocrystals in conquering obstacles for topical delivery. Nanocrystals can improve delivery through the skin by mechanisms like higher concentration gradient across skin resulting in increased passive diffusion, hair follicle targeting, diffusional corona and adhesion to skin. This would be of interest for formulation scientists for product development of molecules that are 'difficult-to-deliver' topically.

Applications of Nanosized-Lipid-Based Drug Delivery Systems in Wound Care

Impaired wound healing is an encumbering public health issue that increases the demand for developing new therapies in order to minimize health costs and enhance treatment efficacy. Available conventional therapies are still unable to maximize their potential in penetrating the skin at the target site and accelerating the healing process. Nanotechnology exhibits an excellent opportunity to enrich currently available medical treatments, enhance standard care and manage wounds. It is a promising approach, able to address issues such as the permeability and bioavailability of drugs with reduced stability or low water solubility. This paper focuses on nanosized-lipid-based drug delivery systems, describing their numerous applications in managing skin wounds. We also highlight the relationship between the physicochemical characteristics of nanosized, lipid-based drug delivery systems and their impact on the wound-healing process. Different types of nanosized-lipid-based drug delivery systems, such as vesicular systems and lipid nanoparticles, demonstrated better applicability and enhanced skin penetration in wound healing therapy compared with conventional treatments. Moreover, an improved chemically and physically stable drug delivery system, with increased drug loading capacity and enhanced bioavailability, has been shown in drugs encapsulated in lipid nanoparticles. Their applications in wound care show potential for overcoming impediments, such as the inadequate bioavailability of active agents with low solubility. Future research in nanosized-lipid-based drug delivery systems will allow the achievement of increased bioavailability and better control of drug release, providing the clinician with more effective therapies for wound care.

Development, Characterization, and Ex Vivo Assessment of Elastic Liposomes for Enhancing the Buccal Delivery of Insulin

Buccal drug delivery is a suitable alternative to invasive routes of drug administration. The buccal administration of insulin for the management of diabetes has received substantial attention worldwide. The main aim of this study was to develop and characterize elastic liposomes and assess their permeability across porcine buccal tissues. Sodium-cholate-incorporated elastic liposomes (SC-EL) and sodium-glycodeoxycholate-incorporated elastic liposomes (SGDC-EL) were prepared using the thin-film hydration method. The prepared liposomes were characterized and their ex vivo permeability attributes were investigated. The distribution of the SC-EL and SGDC-EL across porcine buccal tissues was evaluated using confocal laser scanning microscopy (CLSM). The SGDC-EL were the most superior nanocarriers since they significantly enhanced the permeation of insulin across porcine buccal tissues, displaying a 4.33-fold increase in the permeability coefficient compared with the insulin solution. Compared with the SC-EL, the SGDC-EL were better at facilitating insulin permeability, with a 3.70-fold increase in the permeability coefficient across porcine buccal tissue. These findings were further corroborated based on bioimaging analysis using CLSM. SGDC-ELs showed the greatest fluorescence intensity in buccal tissues, as evidenced by the greater shift of fluorescence intensity toward the inner buccal tissue over time. The fluorescence intensity ranked as follows: SGDC-EL > SC-EL > FITC–insulin solution. Conclusively, this study highlighted the potential nanocarriers for enhancing the buccal permeability of insulin.

Macrophage targeting with the novel carbopol-based miltefosine-loaded transfersomal gel for the treatment of cutaneous leishmaniasis: in vitro and in vivo analyses

OBJECTIVE

The purpose of this study was to develop novel carbopol-based miltefosine-loaded transfersomal gel (HePCTG) for the treatment of cutaneous leishmaniasis (CL) via efficient targeting of leishmania infected macrophages.

METHODS

Miltefosine-loaded transfersomes (HePCT) were prepared by ethanol injection method followed by their incorporation into carbopol gel to form HePCTG. The prepared HePCT were assessed for physicochemical properties including mean particle size, polydispersity index, zeta potential, entrapment efficiency, morphology, and deformability. Similarly, HePCTG was evaluated for physiochemical and rheological attributes. The in vitro release, skin permeation, skin irritation, anti-leishmanial activity, and in vivo efficacy in BALB/c mice against infected macrophages were also performed for HePCT.

RESULTS

The optimized HePCT displayed a particle size of 168 nm with entrapment efficiency of 92%. HePCTG showed suitable viscosity, pH, and sustained release of the incorporated drug. Furthermore, HePCT and HePCTG demonstrated higher skin permeation than drug solution. The results of macrophage uptake study indicated improved drug intake by passive diffusion. The lower half maximal inhibitory concentration value, selectivity index and higher 50% cytotoxic concentration  value of HePCT compared to that of HePC solution demonstrated the improved anti-leishmanial efficacy and non-toxicity of the formulation. This was further confirmed by the notable reduction in parasite load and lesion size observed in in vivo anti-leishmanial study.

CONCLUSION

It can be stated that the formulated HePCTG can effectively be used for the treatment of CL.

The Topical Nanodelivery of Vismodegib Enhances Its Skin Penetration and Performance In Vitro While Reducing Its Toxicity In Vivo

Vismodegib is a first-in-class inhibitor for advanced basal cell carcinoma treatment. Its daily oral doses present a high distribution volume and several side effects. We evaluated its skin penetration loaded in diverse nanosystems as potential strategies to reduce side effects and drug quantities. Ultradeformable liposomes, ethosomes, colloidal liquid crystals, and dendrimers were able to transport Vismodegib to deep skin layers, while polymeric micelles failed at this. As lipidic systems were the most effective, we assessed the in vitro and in vivo toxicity of Vismodegib-loaded ultradeformable liposomes, apoptosis, and cellular uptake. Vismodegib emerges as a versatile drug that can be loaded in several delivery systems for topical application. These findings may be also useful for the consideration of topical delivery of other drugs with a low water solubility.

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.

Development of novel polyglycerol fatty acid ester-based nanoparticles for the dermal delivery of tocopherol acetate

The aim of this study was to develop and evaluate novel polyglycerol fatty acid ester (PGFE)-based nanoparticles (NPs) for the dermal delivery of tocopherol acetate (TA). TA-loaded PGFE-based NPs (PGFE-NPs) were prepared by mixing PGFE, soya phosphatidylcholine, dimyristoylphosphatidylglycerol, and TA with film using the film rehydration and extrusion method. The prepared formulations were analyzed by dynamic light scattering, small-angle X-ray diffraction and polarization microscopy. An in vitro skin accumulation test was performed with TA under occlusive and non-occlusive applications, using Yucatan micropig skin. The size range of the TA-loaded liposome and PGFE-NPs was 107-128 nm, and they were encapsulated in 1.6-2.3 mg/mL TA. All PGFE-NP formulations were negatively charged and stable for 2 weeks. Under occlusive applications, all formulations induced small amounts of TA accumulation in the epidermis but not in the dermis. However, under non-occlusive applications, some of PGFE-NP formulations enhanced TA accumulation in the epidermis. Furthermore, only the polyglycerol 4-laurate (PG4L)-based formulation induced dermal TA accumulation with the change in the formulation from a vesicular to bilayer stacked structure following water evaporation under non-occlusive applications. These results indicated that the novel TA-loaded PG4L formulation enabled the dermal delivery of TA in non-occlusive applications.

Vesicular systems for dermal and transdermal drug delivery

Dermal/transdermal drug delivery continues to grow in importance as a means of enhancing treatment activity while reducing toxicity by avoiding the systemic absorption of the drug. At the same time, this has led to the adjustment of a wide diversity of drug carriers. This paper begins with a review of the skin, including its structure and the parameters that influence drug diffusion, followed by strategies to improve dermal drug delivery. Of the multitude of existing carriers, we will focus on the most advanced vectors in dermal/transdermal delivery, and in particular, on vesicular systems. This review will present the state of the art as well as the new trends in this domain. Through the description of these systems, we will try to obtain information on the ideal properties that the carrier must have in order to improve the cutaneous and transcutaneous penetration of the drug.

Bilosomes as Promising Nanovesicular Carriers for Improved Transdermal Delivery: Construction, in vitro Optimization, ex vivo Permeation and in vivo Evaluation

Purpose

The goal of this research was to enhance the transdermal delivery of lornoxicam (LX), using nanovesicular carriers composed of the bile salt sodium deoxycholate (SDC), soybean phosphatidyl choline (SPC) and a permeation enhancer limonene.

Methods

Thin-film hydration was the technique employed for the fabrication using a Box–Behnken design with three central points. The investigated factors were SPC molar concentration, SDC amount in mg and limonene percentage (%). The studied responses were percent entrapment efficiency (%EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP), and in vitro drug release (after 2, 10 h). In order to obtain the optimum formula, numerical optimization by Design-Expert® software was used. Electing the optimized bilosomal formula was based on boosting %EE, ZP (as absolute value) and in vitro drug release, taking in consideration diminishing PS and PDI. Further assessment of the selected formula was achieved by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), stability testing, ex vivo skin permeation and deposition. The in vivo pharmacodynamics activities of the optimized formula were examined on male rats and mice and compared to that of the oral market product.

Results

The optimized bilosomal formula demonstrated to be nonirritant, with noticeably enhanced anti-inflammatory and antinociceptive activities. Superior in vivo permeation was proved by confocal laser scanning microscopy (CLSM).

Conclusion

The outcomes demonstrated that bilosomes could improve transdermal delivery of lornoxicam.

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A novel nanogel loaded with chitosan decorated bilosomes for transdermal delivery of terbutaline sulfate: artificial neural network optimization, in vitro characterization and in vivo evaluation

The objective of the present work was to formulate, optimize, and evaluate transdermal terbutaline sulfate (TBN)-loaded bilosomes (BLS) in gel, compared to conventional oral TBN solution and transdermal gel loaded with free TBN, aiming at evading the hepatic first-pass metabolism. A face-centered central composite design was adopted to observe the effects of different formulation variables on TBN-BLS, and artificial neural network (ANN) modeling was employed to optimize TBN-BLS. TBN-BLS were prepared by a thin film hydration method integrating soybean phosphatidylcholine and cholesterol as a lipid phase and sodium deoxycholate (SDC) as a surfactant with or without the coating of chitosan (CTS). After being subjected to physicochemical characterization, TBN-BLS were enrolled in a histopathological study and pharmacokinetic investigation in a rat model. The optimized TBN chitosan-coated bilosomes (TBN-CTS-BLS) were spherical vesicles (245.13 ± 10.23 nm) with adequate entrapment efficiency (65.25 ± 5.51%) and good permeation characteristics (340.11 ± 22.34 μg/cm²). The TBN-CTS-BLS gel formulation was well-tolerated with no inflammatory signs manifested upon histopathological evaluation. The pharmacokinetic study revealed that the optimized TBN-CTS-BLS formulation successively enhanced the bioavailability of TBN by about 2.33-fold and increased t_1/2 to about 6.21 ± 0.24 h as compared to the oral solution. These findings support the prospect use of BLS as active and safe transdermal carrier for TBN in the treatment of asthma. Graphical Abstract.

Enhancement of skin permeability with thermal ablation techniques: concept to commercial products

Traditionally, the skin is considered as a protective barrier which acts as a highly impermeable region of the human body. But in recent times, it is recognized as a specialized organ that aids in the delivery of a wide range of drug molecules into the skin (intradermal drug delivery) and across the skin into systemic circulation (transdermal drug delivery, TDD). The bioavailability of a drug administered transdermally can be improved by several penetration enhancement techniques, which are broadly classified into chemical and physical techniques. Application of mentioned techniques together with efforts of various scientific and innovative companies had made TDD a multibillion dollar market and an average of 2.6 new transdermal drugs are being approved each year. Out of various techniques, the thermal ablation techniques involving chemicals, heating elements, lasers, and radiofrequency (RF) are proved to be more effective in terms of delivering the drug across the skin by disrupting the stratum corneum (SC). The reason behind it is that the thermal ablation technique resulted in improved bioavailability, quick treatment and fast recovery of the SC, and more importantly it does not cause any damage to underlying dermis layer. This review article mainly discussed about various thermal ablation techniques with commercial products and patents in each classes, and their safety aspects. This review also briefly presented anatomy of the skin, penetration pathways across the skin, and different generations of TDD.

Advantages of the combined use of cyclodextrins and nanocarriers in drug delivery: A review

Complexation with cyclodextrins (CDs) has been widely and successfully used in pharmaceutical field, mainly for enhancing solubility, stability and bioavailability of a variety of drugs. However, some important drawbacks, including rapid removal from the bloodstream after in vivo administration, or possible replacement, in biological media, of the entrapped drug moieties by other molecules with higher affinity for the CD cavity, can limit the CDs effectiveness as drug carriers. This review is focused on combined strategies simultaneously exploiting CD complexation, and loading of the complexed drug into various colloidal carriers (liposomes, niosomes, polymeric nanoparticles, lipid nanoparticles, nanoemulsions, micelles) which have been investigated as a possible means for circumventing the problems associated with both such carriers, when used separately, and join their relative benefits in a unique delivery system. Several examples of applications have been reported, to illustrate the possible advantages achievable by such a dual strategy, depending on the CD-nanocarrier combination, and mainly resulting in enhanced performance of the delivery system and improved biopharmaceutical properties and therapeutic efficacy of drugs. The major problems and/or drawbacks found in the development of such systems, as well as the (rare) case of failures in achieving the expected improvements have also been highlighted.

Introducing Tween-curcumin niosomes: preparation, characterization and microenvironment study

In this work, we report unusual niosomes (non-ionic surfactant based vesicles), prepared using non-ionic surfactant Tween 80 (T80) as well as Tween 20 (T20) and curcumin. Conventional niosomes consist of non-ionic surfactant and cholesterol. We found that, despite being a probiotic, curcumin plays a similar role to cholesterol in the formation and stabilization of niosomes. The prepared Tween-curcumin niosomes were characterised using Dynamic Light Scattering (DLS), zeta potential, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) techniques. The curcumin-induced micelle to vesicle transition in the Tween surfactants was investigated by DLS, zeta potential, fluorescence anisotropy, and fluorescence lifetime studies. At room temperature (298 K), the prepared niosomes were found to be stable; however, at a higher temperature (333 K), the niosomes degrade gradually and irreversibly to form micelles. The temperature-dependent vesicle to micelle degradation was monitored using fluorescence anisotropy, absorption, DLS and Differential Scanning Calorimetry (DSC) measurements. Further, the Tween-curcumin niosomes show a controlled release of curcumin, which could open up the possibility of multidrug therapy.

Antibiotic Delivery Strategies to Treat Skin Infections When Innate Antimicrobial Defense Fails

The epidermal skin barrier protects the body from a host of daily challenges, providing protection against mechanical insults and the absorption of chemicals and xenobiotics. In addition to the physical barrier, the epidermis also presents an innate defense against microbial overgrowth. This is achieved through the presence of a diverse collection of microorganisms on the skin (the "microbiota") that maintain a delicate balance with the host and play a significant role in overall human health. When the skin is wounded, the local tissue with a compromised barrier can become colonized and ultimately infected if bacterial growth overcomes the host response. Wound infections present an immense burden in healthcare costs and decreased quality of life for patients, and treatment becomes increasingly important because of the negative impact that infection has on slowing the rate of wound healing. In this review, we discuss specific challenges of treating wound infections and the advances in drug delivery platforms and formulations that are under development to improve topical delivery of antimicrobial treatments.

Rifampicin-loaded nanotransferosomal gel for treatment of cutaneous leishmaniasis: passive targeting via topical route

Aim: In this study, the targeting of rifampicin (RIF)-loaded nanotransfersomes (NTs) incorporated in chitosan gel for leishmania-infected macrophages via the topical route was investigated. Materials & methods: NTs were prepared through a thin-film hydration process and incorporated into chitosan gel. Results: The mean particle size of the NTs was 190 nm, with 83% encapsulation efficiency. The permeation rate of the NTs was threefold higher than that of the RIF solution. The NTs improved cellular internalization via passive targeting, which was confirmed by macrophage uptake evaluation. A low IC₅₀ value, flow cytometry analysis and in vivo study demonstrated the RIF-loaded NTs enhanced apoptosis and had better antileishmanial effects. Conclusion: RIF-loaded NT gel could be a fitting carrier for the delivery of antileishmanial drugs in cutaneous leishmaniasis.

Conformational dynamics and phase behavior of lipid vesicles in a precisely controlled extensional flow

Lipid vesicles play a key role in fundamental biological processes. Despite recent progress, we lack a complete understanding of the non-equilibrium dynamics of vesicles due to challenges associated with long-time observation of shape fluctuations in strong flows. In this work, we present a flow-phase diagram for vesicle shape and conformational transitions in planar extensional flow using a Stokes trap, which enables control over the center-of-mass position of single or multiple vesicles in precisely defined flows [A. Shenoy, C. V. Rao and C. M. Schroeder, Proc. Natl. Acad. Sci. U. S. A., 2016, 113(15), 3976-3981]. In this way, we directly observe the non-equilibrium conformations of lipid vesicles as a function of reduced volume ν, capillary number Ca, and viscosity contrast λ. Our results show that vesicle dynamics in extensional flow are characterized by the emergence of three distinct shape transitions, including a tubular to symmetric dumbbell transition, a spheroid to asymmetric dumbbell transition, and quasi-spherical to ellipsoid transition. The experimental phase diagram is in good agreement with recent predictions from simulations [V. Narsimhan, A. P. Spann and E. S. Shaqfeh, J. Fluid Mech., 2014, 750, 144]. We further show that the phase boundary of vesicle shape transitions is independent of the viscosity contrast. Taken together, our results demonstrate the utility of the Stokes trap for the precise quantification of vesicle stretching dynamics in precisely defined flows.

Nanoparticles for topical drug delivery: Potential for skin cancer treatment

Nanoparticles offer new opportunities for the treatment of skin diseases. The barrier function of the skin poses a significant challenge for nanoparticles to permeate into the tissue, although the barrier is partially compromised in case of injury or inflammation, as in the case of skin cancer. This may facilitate the penetration of nanoparticles. Extensive research has gone into developing nanoparticles for topical delivery; however, relatively little progress has been made in translating them to the clinic for treating skin cancers. We summarize the types of skin cancers and practices in current clinical management. The review provides a comprehensive outlook of the various nanoparticle technologies tested for topical therapy of skin cancers and summarizes the obstacles that impede its progress from the bench-to-bedside. The review also aims to provide an understanding of the pathways that govern nanoparticle penetration into the skin and a critical analysis of the approaches used to study nanoparticle interactions within the tissue.

Premium ethylcellulose polymer based architectures at work in drug delivery

Premium ethylcellulose polymers are hydrophobic cellulose ether based biomaterials widely employed as biocompatible templates for the design of novel drug delivery systems. They are classified as United States Food and Drug Administration Generally-Recognized-As-Safe chemical substances and have been extensively utilized within the biomedical and pharmaceutical industries for over half a century. They have so far demonstrated the potential to modulate and improve the physiological performance of bioactives leading to the desired enhanced prophylactic and therapeutic outcomes. This review therefore presents a scholarly survey of inter-disciplinary developments focused on the functionalities of ethylcellulose polymers as biomaterials useful for the design of smart delivery architectures for relevant pharmacotherapeutic biomedical applications. Emphasis was placed on evaluating scientific resources related to recent advancements and future directions associated with its applications as delivery systems for drugs and biologics within the past decade thus complementing other specialized reviews showcasing the theme.

Development of tizanidine loaded aspasomes as transdermal delivery system: ex-vivo and in-vivo evaluation

New generation of amphiphilic vesicles known as aspasomes were investigated as potential carriers for transdermal delivery of tizanidine (TZN). Using full factorial design, an optimal formulation was developed by evaluating the effects of selected variables on the properties of the vesicles with regards to entrapment efficiency, vesicle size and cumulative percentage released. The optimal formula (TZN-AS 6) consisting of 20 mg TZN, 50 mg ascorbyl palmitate (AP), 50 mg cholesterol (CH) and 50 mg Span 60, represented well dispersed spherical vesicles in the nanorange sizes and exhibited excellent stability under different storage conditions. Ex-vivo permeation studies using excised rat skin showed a 4.4-fold increase of the steady state flux in comparison to the unformulated drug (p < 0.05). The pharmacokinetic parameters obtained from the in-vivo study using Wistar rats, showed that the bioavailability of TZN was enhanced significantly (p < 0.05) when compared to the oral market product of TZN, Sirdalud^®. Moreover, skin irritancy tests confirmed that the vesicles were non-invasive and safe for the skin. Based on the results obtained, the optimised aspasomes formula represents a promising Nano platform for TZN to be administered transdermally, thus improving the therapeutic efficacy of this important muscle relaxant.

Stabilization of Deformable Nanovesicles Based on Insulin-Phospholipid Complex by Freeze-Drying

Deformable nanovesicles have been extensively investigated due to their excellent ability to penetrate biological barriers. However, suffering from serious physical and chemical instabilities, the wide use of deformable nanovesicles in medical applications is still limited. Moreover, far less work has been done to pursue the lyophilization of deformable nanovesicles. Here, we aimed to obtain stable deformable nanovesicles via freeze-drying technology and to uncover the underlying protection mechanisms. Firstly, the density of nanovesicles before freeze-drying, the effect of different kinds of cryoprotectants, and the types of different reconstituted solvents after lyophilization were investigated in detail to obtain stable deformable nanovesicles based on insulin-phospholipid complex (IPC-DNVs). To further investigate the underlying protection mechanisms, we performed a variety of analyses. We found that deformable nanovesicles at a low density containing 8% lactose and trehalose in a ratio of 1:4 (8%-L-T) have a spherical shape, smooth surface morphology in the lyophilized state, a whorl-like structure, high entrapment efficiency, and deformability after reconstitution. Importantly, the integrity of IPC, as well as the secondary structure of insulin, were well protected. Accelerated stability studies demonstrated that 8%-L-T remained highly stable during storage for 6 months at 25 °C. Based on in vivo results, lyophilized IPC-DNVs retained their bioactivity and had good efficacy. Given the convenience of preparation and long term stability, the use of combined cryoprotectants in a proper ratio to protect stable nanovesicles indicates strong potential for industrial production.

Loading of water-insoluble celastrol into niosome hydrogels for improved topical permeation and anti-psoriasis activity

Psoriasis is a severe disfiguring skin disease affecting approximately 3% of people worldwide and negatively affecting their daily lives. The pathogenesis of psoriasis is complicated, and typical therapeutic strategies for psoriasis mainly focus on anti-inflammation. Considering the side effects, withdrawal rebound, high cost, and many other disadvantages of existing treatments, we developed a new topical therapeutic formulation consisting of niosomes loaded with celastrol, a triterpenoid extracted from Tripterygium. Celastrol niosomes were prepared by the thin film hydration method and probe sonication. The niosomes were composed of Span 20, Span 60, and cholesterol at a weight ratio of 3:1:1. The particle size of the niosomes was approximately 147 nm, with yield of up to 90%. Celastrol niosomes showed improved in vitro permeation ability compared to the raw drug. In our in vivo study, celastrol niosomes effectively alleviated erythema and scaling on the dorsal skin of psoriasis mouse models. Spleen weight and the levels of cytokines, including IL-22, IL-23, and IL-17, decreased after the treatment, indicating the high therapeutic potential of this formulation for psoriasis. In conclusion, encapsulation of celastrol by niosomes increased the water-solubility and permeation of celastrol into the skin, significantly improving its anti-psoriasis activity in mice.

Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), ³¹P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten^®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten^®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.

Stimulus Sensitive Smart Nanoplatforms: An Emerging Paradigm for the Treatment of Skin Diseases

Background:

Over the past century, the prevalence of skin diseases has substantially increased. These diseases present a significant physical, emotional and socio-economic burden to the society. Such conditions are also associated with a multitude of psychological traumas to the suffering patients. The effective treatment strategy implicates targeting of drugs to the skin. The field of drug targeting has been revolutionized with the advent of nanotechnology. The emergence of stimulus-responsive nanoplatforms has provided remarkable control over fundamental polymer properties for external triggers. This enhanced control has empowered pioneering approaches in the treatment of chronic inflammatory skin diseases.

Objective:

Our aim was to investigate the studies on smart nanoplatforms that exploit the altered skin physiology under diseased conditions and provide site-specific controlled drug delivery.

Method:

All literature search regarding the advances in stimulus sensitive smart nanoplatforms for skin diseases was done using Google Scholar and Pubmed.

Conclusion:

Various stimuli explored lately for such nano platforms are pH, temperature, light and magnet. Although, the scientists have actively taken up this research topic but there are still certain lacunaes associated which have been discussed in this review. Further, an interdisciplinary collaboration between the healthcare providers and pharmacists is a pivotal requirement for such systems to be available for patients.