Liposomes and niosomes as topical drug carriers: dermal and transdermal drug delivery

Potential of Nanoparticles as Permeation Enhancers and Targeted Delivery Options for Skin: Advantages and Disadvantages

The topical route of administration has many advantages for the treatment of various skin disorders as well as cosmeceutical purposes. This route bypasses hepatic first-pass effect and systemic availability of many pharmaceuticals is limited to skin organelles such as hair follicles and so could avoid unwanted adverse reactions and increase the localized therapeutic effect. Despite such attributed advantages of the topical route, the most important challenge is skin barrier characteristics that should be overcome to obtain dermal or trans-dermal drug delivery. Different approaches have been recruited to overcome this barrier. In this review, different types of nanoparticles for skin permeation enhancement and targeted delivery to skin organelles are discussed. The potential mechanisms of each nanocarrier in permeation enhancement and dermal delivery are considered and finally, the most important advantages and disadvantages of each group are summarized.

Skin Permeation of Nanoparticles: Mechanisms Involved and Critical Factors Governing Topical Drug Delivery

Transdermal route has been an ever sought-after means of drug administration, regarded as being the most convenient and patient compliant. However, skin poses a great barrier to the entry of the external particles including bacteria, viruses, allergens, and drugs as well (mostly hydrophilic or high molecular weight drugs), consequent to its complex structure and composition. Among the various means of enhancing drug permeation through the skin, e.g. chemical permeation enhancers, electroporation, thermophoresis, etc. drug delivery through nanoparticles has been of great interest. Current literature reports a vast number of nanoparticles that have been implicated for drug delivery through the skin. However, a precise account of critical factors involved in drug delivery and mechanisms concerning the permeation of nanoparticles through the skin is necessary. The purpose of this review is to enumerate the factors crucial in governing the prospect of drug delivery through skin and classify the skin permeation mechanisms of nanoparticles. Among the various mechanisms discussed are the ones governed by principles of kinetics, osmotic gradient, adhesion, hydration, diffusion, occlusion, electrostatic interaction, thermodynamics, etc. Among the most common factors affecting skin permeation of nanoparticles that are discussed include size, shape, surface charge density, composition of nanoparticles, mechanical stress, pH, etc.

A new formulation of hydrophobin-coated niosome as a drug carrier to cancer cells

Hydrophobin-1 (HFB-1) found on the surface of fungal spores, plays a role in the lack of antigen recognition by the host immune system. The present study aimed to evaluate the potential application of HFB-1 for the delivery of doxorubicin (Dox) into different cell lines. Coating the surface of niosomes (Nio) with HFB-1 leads to the hypothesis that this protein can confer protection against in vivo immune-system recognition and prevent the immune response. Thus, HFB-1 could become a promising alternative to polyethylene glycol (PEG). Here, HFB-1-coated niosome loaded with doxorubicin (Dox) based on Span 40, Tween 40 and cholesterol was prepared and compared with the PEG-coated niosome. Physicochemical characteristics of the prepared formulations in terms of size, zeta potential, polydispersity index (PDI), morphology, entrapment efficiency (EE), and release rate were evaluated at different pH levels (2, 5.2, and 7.4). In the end, the in vitro cytotoxicity assay was performed on four different cancer cell lines namely A549, MDA-MB-231, C6 and PC12 in addition to one control cell line (3 T3) to ensure the formulation's selectivity against cancer cells. Results showed that the niosomes coated with HFB-1 presented better size distribution, higher EE, more sustained release profile, enhanced biocompatibility and improved anticancer effects as compared to the PEG-coated niosomes. Interestingly, the viability percentage of the control cell line was higher than different cancer cells when treated with the formulations, which indicates the higher selectivity of the formulation against cancer cells. In conclusion, loading the niosomes with Dox and coating them with HFB-1 enhanced their efficacy and selectivity toward cancer cells, presenting a promising drug delivery system for sustained drug release in cancer treatment.

How an organogelator can gelate water: gelation transfer from oil to water induced by a nanoemulsion

A hydrogel can be formed by an organogelator in the presence of a nanoemulsion. It is expected that this is due to a gelation transfer from oil to water. The system started with an oil-in-water nanoemulsion prepared according to a phase inversion temperature (PIT) process. Into this nanoemulsion consisting of Kolliphor® RH40 and Brij® L4 as surfactants, and Miglyol® 812 as oil and water, we introduced the organogelator 12-hydroxyoctadecanoic acid (12-HOA) in the oil phase. After cooling at room temperature, a slow reversible gelation of the water phase occurred with persistence of the nanoemulsion. This thermally reversible system was investigated using various techniques (rheology, turbidimetry, optical and electron microscopies, scattering techniques). Successive stages appeared during the cooling process after the nanoemulsion formation, corresponding to the migration and self-assembly of the organogelator from the oil nanodroplets to the water phase. According to our measurements and the known self-assembly of 12-HOA, a mechanism explaining the formation of the gelled nanoemulsion is proposed.

Methylene blue-loaded niosome: preparation, physicochemical characterization, and in vivo wound healing assessment

Following skin injury, the overproduction of reactive oxygen species (ROS) during the inflammatory phase can cause tissue damage and delay in wound healing. Methylene blue (MB) decreases mitochondrial ROS production and has antioxidant effects. The authors aimed to prepare MB-loaded niosomes using the ultra-sonication technique as a green formulation method. A Box-Behnken design was selected to optimize formulation variables. The emulsifier to cholesterol ratio, HLB of mixed surfactants (Span 60 and Tween 60), and sonication time were selected as independent variables. Vesicle size, zeta potential (ZP), and drug entrapment capacity percentage were studied as dependent variables. The optimized formulation of niosomes showed spherical shape with optimum vesicle size of 147.8 nm, ZP of - 18.0 and entrapment efficiency of 63.27%. FTIR study showed no observable interaction between MB and other ingredients. In vivo efficacy of optimized formulation was evaluated using an excision wound model in male Wistar rat. Superoxide dismutase (SOD, an endogenous antioxidant) and malondialdehyde (MDA, an end product of lipid peroxidation) levels in skin tissue samples were evaluated. After 3 days, MDA was significantly decreased in niosomal gel-treated group, whereas SOD level was increased. Histological results indicate rats that received niosomal MB were treated effectively faster than other ones. Graphical abstract.

Transfersomes — A Nanoscience in Transdermal Drug Delivery and Its Clinical Advancements

The convenient nanotransdermal delivery system is always likely to have some ideal and unique characteristics, predominantly for safety, desired actions, clinical efficacy, enriched with a therapeutic index with minimal adverse occurrence. One of the most challenging tasks for the formulators is to transfer the medicament, especially macromolecules, through the skin. Some of the ways to achieve this is the use of a painful needle or some other methods which also have economical constraints. A new technology has been developed, that is ultradeformable liposomes, also called as transfersomes. These are an elastic type of lipid vesicle aggregates capable of delivering wide range of active moieties including various biomolecules. It can be manufactured by evaporation, vortexing, reverse-phase evaporation, ethanol injection or freeze-thaw methods, where phospholipids and edge activators are the major ingredients that contribute the main role in their unique mechanism of permeation through less permeable stratum corneum. This review mainly focuses on the clinical trial studies and patents accessible on transfersomal products worldwide, highlights the recent work on transfersomes with various therapeutic agents. An effort to explain the deeper penetration of transfersomes across the epidermis layer by its pharmacokinetics and dynamic properties has been taken.

Ferritin Nanocage Conjugated Hybrid Hydrogel for Tissue Engineering and Drug Delivery Applications

Hydrogels have recently been attractive in various drug delivery and tissue engineering applications because of their structural similarities to the natural extracellular matrix. Despite enormous advances in the application of hydrogels, poor mechanical properties and lack of control for the release of drugs and biomolecules act as major barriers for widespread clinical applications. To overcome these challenges, we developed both physically and covalently conjugated nanocage-laden hydrogels between the surface of the nanocage and a gelatin methacryloyl (GelMA) hydrogel matrix. Ferritin and its empty-core equivalent apoferritin were used as nanocages that could be easily incorporated into a GelMA hydrogel via physical bonding. To fabricate covalently conjugated nanocage-laden GelMA hydrogels, ferritin and apoferritin were chemically modified to present the methacryloyl groups, ferritin methacryloyl (FerMA) and apoferritin methacryloyl (ApoMA), respectively. The covalently conjugated FerMA- and ApoMA-GelMA hydrogels offered a better ability to tune mechanical properties compared with those prepared by direct dispersion of ferritin and apoferritin into GelMA hydrogels with physical bonding, without affecting their porosity or cell growth. Furthermore, the ability of the nanocage to release small chemical compounds was confirmed by performing a cumulative release test on fluorescein isothiocyanate (FITC) encapsulated apoferritin and ApoMA incorporated GelMA hydrogels by pH stimulus. Thus, the nanocage incorporated hydrogels have emerged as excellent materials for drug delivery and tissue engineering applications.

A brief overview on nano-sized materials used in the topical treatment of skin and soft tissue bacterial infections

Introduction: Skin and soft tissue infections are a significant clinical problem that can happen anywhere on the body. Bacteria are the most common cause of skin and soft tissue infections in humans. Despite the fact that there is a lot of antimicrobial agents and antibiotics for elucidating bacterial infections, the prevention and control of infectious diseases continue to be one of the greatest challenges for public health worldwide. At the present time, an alarming increase in multidrug resistance instantly requests to find suitable alternatives to current antibiotics. Therefore, drug resistance has been attempted to be resolved by the development of new classes of antimicrobial agents or targeted delivery systems for antibacterial drugs using nanotechnology.Area covered: The present review summarizes the emerging topical efforts to support the use of nano-sized materials as a new opportunity to combat today's skin infectious diseases.Expert opinion: Nano-sized materials can overcome the stratum corneum barrier and deliver drugs specifically to bacterial skin infections with trivial side effects. Depending on the physicochemical characteristics of nano-scaled materials, they can specifically be selected to target bacterial pathogens and also to get into the skin layers. These systems can overcome the antibiotic-resistance mechanisms and help us to the design of novel topical formulations that will make administration of antibacterial compounds safer, easier and more convenient.

[Topical drug administration to the inner ear. Modern state of the problem and development perspectives]

The work assessed modern methods of drug delivery through biological barriers to the lesion, in particular, through the most studied - skin. The main advantages and disadvantages of the existing methods for the topical administration of drugs into the inner ear - intra-imperial and intra-labyrinth delivery are analyzed. A brief review of medicinal substances for topical administration to the inner ear, both widely used (for example, aminoglycosides, steroid drugs) and undergoing clinical trials, is given. An assessment is made of the prospects for the use of transmembrane drug delivery to the inner ear using an electric field, which has a combined electro-creative and iontophoretic effect.

3D Printed Microheater Sensor-Integrated, Drug-Encapsulated Microneedle Patch System for Pain Management

Microneedle patch devices have been widely utilized for transdermal drug delivery in pain management, but is challenged by accurate control of drug release and subsequent diffusion to human body. The recent emerging wearable electronics that could be integrated with microneedle devices offer a facile approach to address such a challenge. Here a 3D-printed microheater integrated drug-encapsulated microneedle patch system for drug delivery is presented. The ink solution comprised polydimethylsiloxane (PDMS) and multiwalled carbon nanotubes (MWCNTs) with a mass concentration of up to 45% (≈10 times higher of existing ones) is prepared and used to print crack-free stretchable microheaters on substrates with a broad range of materials and geometric curves. The adhesion strength of the printed microheater on the microneedle patch in elevated temperatures is measured to evaluate their integration performance. Assessments of encapsulated drug release into rat's skin are confirmed by examining degradation of microneedles, skin morphologies, and released fluorescent signals. Results and demonstrations established here creates a new opportunity for developing sensor controlled smart microneedle patch systems by integrating with wearable electronics, potentially useful in clinical and biomedical research.

Phospholipid-Free Small Unilamellar Vesicles for Drug Targeting to Cells in the Liver

It is reported that cholesterol (Chol) and TWEEN 80 at a molar ratio of 5:1 can form small unilamellar vesicles (SUVs) using a staggered herringbone micromixer. These phospholipid-free SUVs (PFSUVs) can be actively loaded with a model drug for targeting hepatocytes via the endogenous apolipoprotein mechanism. PFSUVs particles with compositions of Chol:TWEEN 80 ranging between 1.5:1 and 5:1 (mol/mol) can be produced with a mean diameter of ≈80 nm, but only the high-Chol formulations (3:1 and 5:1) can retain a transmembrane gradient of ammonium sulfate for active loading of doxorubicin (DOX). Under cryo-transmission electron microscopy, PFSUVs-DOX displays a unilamellar bilayer structure with DOX molecules forming spindle-shape aggregates inside the aqueous core. Relative to PEGylated liposomal doxorubicin (PLD) that exhibits little interaction with cells in various conditions, the cellular uptake of PFSUVs-DOX is dependent on the presence of serum and enhanced with an increased concentration of apolipoproteins. After intravenous injection, the vast majority of PFSUVs-DOX accumulates in the liver and DOX is detected in all liver cells (predominantly the hepatocytes), while PLD is captured only by the sinusoidal cells (i.e., macrophages). This report discloses an innovative lipid bilayer vesicle for highly efficient and selective hepatocyte targeting.

In Vitro and In Vivo Profiles and Characterization of Insulin Nanocarriers Based in Flexible Liposomes Designed for Oral Administration

Background:

Alternatives routes of delivery for Insulin have been evaluated to improve treatment for Diabetes Mellitus. The oral route is the most convenient physiologically; it releases in a similar way to endogenous secretion. Flexible liposomes have deformable abilities to pass through membranes with adequate therapeutic effects, but they have been tested only dermally.

Objective:

Our aim was to develop an oral nanocarrier based on flexible liposomes for insulin with polymer addition to reduce gastrointestinal degradation.

Methods:

Different percentages of polyethylene glycol were added to a conventional formulation of flexible liposomes. The manufacturing procedure was the heating method. Z potential, size particle, polydispersity index and encapsulation percentage were evaluated. A release profile was performed in the stomach and intestinal pH mediums by two-stage reverse dialysis method. The in-vivo test was performed in experimental diabetic rats by oral, transdermal and subcutaneous routes.

Results:

All the formulations showed polydispersity but adequate Z potential. The 10% PEG formulation obtained the best insulin enclosure with 81.9%. The insulin integrity after preparation was confirmed by polyacrylamide gel electrophoresis. PEG and non-PEG formulations showed similar behavior in acid release profile but the release and stability of lipid structures were better and longer in intestinal pH conditions. In vivo tests showed a reduction to normal glucose levels only in subcutaneous route.

Conclusion:

The polymer inclusion in flexible liposomes generates an adequate nanocarrier for proteins in terms of stability and composition; although its in-vivo use reduces glucose levels in subcutaneous route, the effect was not adequate in oral route.

Effects of Temperature and Humidity on the Skin Permeation of Hydrophilic and Hydrophobic Drugs

The humidity was a well-known method to hydrate the skin; however, the published data were varied, and systemic experiments in the previous papers were few. Therefore, the in vitro permeation of excised porcine ear skin by drugs with different polarities [aminopyrine (AMP), antipyrine (ANP), methylparaben (MP), and ibuprofen (IP)] was analyzed under a constant skin surface temperature with different temperatures and humidities to reveal the effects of temperature and humidity on the skin permeation enhancement effects. Applied formulations were prepared by mixing the drug and a hydrophilic vehicle containing glycerin. The disposition-distance profiles of water and the humectant glycerin in the stratum corneum were also investigated using confocal Raman microscopy. High absolute humidity (AH) significantly contributed to the high skin penetration of the hydrophilic penetrants AMP, ANP, and MP but not the hydrophobic penetrant IP. An increase in the partition parameter and a decrease in the diffusivity parameter occurred with an increase in AH, independent of drug polarity. Moreover, we found that dew condensation induced by high AH on temperature-controlled skin surface may effectively increase water content and may provide higher glycerin distribution in the skin barrier, the stratum corneum. Increasing the amount of water and hydrophilic vehicles such as glycerin in the stratum corneum may enhance the permeation of hydrophilic penetrants AMP, ANP, and MP. These data suggested a dew condensation on the skin surface induced by high AH at a constant skin surface temperature would be important to enhance hydrophilic penetrants.

Liposomes for delivery of antioxidants in cosmeceuticals: Challenges and development strategies

Antioxidants (AOs) play a crucial role in the protection and maintenance of health and are also integral ingredients in beauty products. Unfortunately, most of them are sensitive due to their instability and insolubility. The use of liposomes to protect AOs and expand their applicability to cosmeceuticals, thereby, is one of the most effective solutions. Notwithstanding their offered advantages for the delivery of AOs, liposomes, in their production and application, present many challenges. Here, we provide a critical review of the major problems complicating the development of liposomes for AO delivery. Along with issues related to preparation techniques and encapsulation efficiency, the loss of protective function and inefficiency of skin permeability are the main disadvantages of liposomes. Corresponding development strategies for resolving these problems, with their respective advantages and drawbacks, are introduced, discussed in some depth, and summarized in these pages as well. Advanced liposomes have a vital role to play in the development and delivery of AOs in practical cosmeceutical product applications.

Selected Physicochemical Properties of Lyophilized Hydrogel with Liposomal Fraction of Calcium Dobesilate

Lyophilization is the process of drying and improving the stability of various pharmaceutical preparations. In this work we evaluated the properties of 11 hydrophilic gels calcium dobesilate with liposomes based on soybean lecithin, subjected to the freeze-drying procedure. Liposomes were produced by using method thin lipid film. Lyophilization was carried out under conditions of temperature equal (-30 °C) and pressure 0.37 mbar. We evaluated the preparations with dynamic light scattering (DLS) method, optical microscopy and Fourier-transform infrared spectroscopy (FTIR). In this work we presented the average results for the particle diameter in the sample and PDI (polydispersity index) value for the samples that produced the results. When testing using the DLS method on a Malvern Zetaseizer, results for 7 samples were not obtained. Two of next four samples were characterized by an increased size of the liposome particle resulting from a lower concentration of ethanol compared to the rest of them. Three samples under the microscope did not show any differences. It was possible only to see single crystals probably of undissolved calcium dobesilate. Some clusters were observed in the 4 samples, and when they appeared they were very small. The aggregates and irregular liposomes present in the rest of the samples may have been formed due to the destabilizing activity of ethanol towards lipid membranes. In the FTIR spectrum for MC, the peak was observed at the wavenumber of ca. 2900 cm-1 and of about 1050 cm-1. In case of pure calcium dobesilate we observed low pick at the wavenumber of about 3400 cm-1. The spectrum has a low peak at the wavenumber of 1450 cm-1 and intense peaks ranging from approx. 1000 cm-1 to approx. 1200 cm-1. Decay of the lecithin peak in formulations with liposomes at 1725 cm-1 wavelength may indicate the occurrence of the hydrolysis reaction in the system. Probably there was a hydrolysis of the ester bond connecting the rest of the phosphoric acid and the choline with the glycerol residue.

Magnetic delivery of antitumor carboplatin by using PEGylated-Niosomes

To improve the efficiency of niosomal drug delivery, here we employed two tactics. First, niosomes were magnetized using Fe3O4@SiO2 mangnetic nanoparticles, and second, their surface was modified by PEGylation. PEGylation was intended for increasing the bioavailability of niosomes, and magnetization was used for rendering them capable of targeting specific tissues. These PEGylated magnetic niosomes were also loaded with Carboplatin, an antitumor drug. Next, these niosomes were studied in terms of size, morphology, zeta potential, and drug entrapment efficiency. Then, the in vitro drug release from these modified niosomes was compared to that of both naked and nonmagnetized niosomes. Interestingly, although loading of naked-niosomes with magnetic particles lead to an increase in the rate of drug release, PEGylation of these magnetized niosomes caused a more sustained drug release. Thus, PEGylation of magnetic niosomes, besides improving their bioavailability, caused a slower and sustained release of the drug over time. Finally, studying the in vitro effectives of niosomal formulations towards MCF-7, a breast cancer cell line, showed that PEGylated magnetic niosomes had a satisfactory toxicity towards these cells in the presence of an external magnetic field. In conclusion, PEGylated magnetic niosomes showed enhanced qualities regarding the controlled release and delivery of drug. Graphical abstract ᅟ.

Smart Bandages: The Future of Wound Care

Chronic non-healing wounds are major healthcare challenges that affect a noticeable number of people; they exert a severe financial burden and are the leading cause of limb amputation. Although chronic wounds are locked in a persisting inflamed state, they are dynamic and proper therapy requires identifying abnormalities, administering proper drugs and growth factors, and modulating the conditions of the environment. In this review article, we discuss technologies that have been developed to actively monitor the wound environment. We also highlight drug delivery tools that have been integrated with bandages to facilitate precise temporal and spatial control over drug release and review automated or semi-automated systems that can respond to the wound environment.

Lawsone-loaded Niosome and its antitumor activity in MCF-7 breast Cancer cell line: a Nano-herbal treatment for Cancer

Phytochemicals like Lawsone have some drawbacks that stem from their poor solubility. Low solubility in aqueous mediums results in low bioavailability, poor permeability and instability of phytochemical compounds in biological environments. The aim of this study was to design nanoniosomes containing Lawsone (Law) using non-ionic surfactants and cholesterol. Niosomes were prepared by thin film hydration method (TFH). Then, they were loaded with Henna extract (HLaw) and standard Lawsone (SLaw), and two resulted formulations were compared. The henna extract was analyzed by mass gas chromatography. Size, zeta potential, polydispersity index (PDI) and morphology of the loaded formulations were evaluated by dynamic light scattering (DLS) and scanning electron spectroscopy (SEM). The incorporation and release rate of Law from niosome bilayers were evaluated by UV-Vis spectroscopy. In vitro experiments were carried out to evaluate antitumor activity in MCF-7 cell line. The results showed distinct spherical shapes and particle sizes were about 250 nm in diameter and have negative zeta potentials. Niosomes were stable at 4 °C for 2 months. Entrapment efficiently of both formulations was about 70% and showed a sustained release profile. In vitro study exhibited that using of niosome to encapsulating Law can significantly increase antitumor activity of formulation in MCF-7 cell line compared to Law solution (free Law). Thus, niosomes are a promising carrier system for delivery of phytochemical compounds that have poor solubility in biological fluids. Graphical abstract ᅟ.

Development and evaluation of exemestane-loaded lyotropic liquid crystalline gel formulations

Introduction: The use of liquid crystalline (LC) gel formulations for drug delivery has considerably improved the current delivery methods in terms of bioavailability and efficacy. The purpose of this study was to develop and evaluate LC gel formulations to deliver the anti-cancer drug exemestane through transdermal route. Methods: Two LC gel formulations were prepared by phase separation coacervation method using glyceryl monooleate (GMO), Tween 80 and Pluronic® F127 (F127). The formulations were characterized with regard to encapsulation efficiency (EE), vesicle size, Fourier transform infrared (FTIR) spectroscopy, surface morphology (using light and fluorescence microscopy), in vitro release, ex vivo permeation, in vitro effectiveness test on MDA-MB231 cancer cell lines and histopathological analysis. Results: Results exhibited that the EE was 85%-92%, vesicle size was 119.9-466.2 nm while morphology showed spherical vesicles after hydration. An FTIR result also revealed that there was no significant shift in peaks corresponding to Exemestane and excipients. LC formulations release the drug from cellulose acetate and Strat-MTM membrane from 15%-88.95%, whereas ex vivo permeation ranges from 37.09-63%. The in vitro effectiveness study indicated that even at low exemestane concentrations (12.5 and 25 μg/mL) the formulations were able to induce cancer cell death, regardless of the surfactant used. Histopathological analysis thinning of the epidermis as the formulations penetrate into the intercellular regions of squamous cells. Conclusion: The results conjectured that exemestane could be incorporated into LC gels for the transdermal delivery system and further preclinical studies such as pharmacokinetic and pharmacodynamic studies will be carried out with suitable animal models.

Effective Skin Cancer Treatment by Topical Co-delivery of Curcumin and STAT3 siRNA Using Cationic Liposomes

The aim of the present study was to evaluate the effectiveness of iontophoretic co-delivery of curcumin and anti-STAT3 siRNA using cationic liposomes against skin cancer. Curcumin was encapsulated in DOTAP-based cationic liposomes and then complexed with STAT3 siRNA. This nanocomplex was characterized for the average particle size, zeta-potential, and encapsulation efficiency. The cell viability studies in B16F10 mouse melanoma cells have shown that the co-delivery of curcumin and STAT3 siRNA significantly (p < 0.05) inhibited the cancer cell growth compared with either liposomal curcumin or STAT3 siRNA alone. The curcumin-loaded liposomes were able to penetrate up to a depth of 160 μm inside the skin after iontophoretic (0.47 mA/cm²) application. The in vivo efficacy studies were performed in the mouse model of melanoma skin cancer. Co-administration of the curcumin and STAT3 siRNA using liposomes significantly (p < 0.05) inhibited the tumor progression as measured by tumor volume and tumor weight compared with either liposomal curcumin or STAT3 siRNA alone. Furthermore, the iontophoretic administration of curcumin-loaded liposome-siRNA complex showed similar effectiveness in inhibiting tumor progression and STAT3 protein suppression compared with intratumoral administration. Taken together, cationic liposomes can be utilized for topical iontophoretic co-delivery of small molecule and siRNA for effective treatment of skin diseases.

Degree of Unsaturation and Backbone Orientation of Amphiphilic Macromolecules Influence Local Lipid Properties in Large Unilamellar Vesicles

Liposomes have become increasingly common in the delivery of bioactive agents due to their ability to encapsulate hydrophobic and hydrophilic drugs with excellent biocompatibility. While commercial liposome formulations improve bioavailability of otherwise quickly eliminated or insoluble drugs, tailoring formulation properties for specific uses has become a focus of liposome research. Here, we report the design, synthesis, and characterization of two series of amphiphilic macromolecules (AMs), consisting of acylated polyol backbones conjugated to poly(ethylene glycol) (PEG) that can serve as the sole additives to stabilize and control hydrophilic molecule release rates from distearoylphosphatidylcholine (DSPC)-based liposomes. As compared to DSPC alone, all AMs enable liposome formation and stabilize their colloidal properties at low incorporation ratios, and the AM's degree of unsaturation and hydrophobe conformation have profound impacts on stability duration. The AM's chemical structures, particularly hydrophobe unsaturation, also impact the rate of hydrophilic drug release. Course-grained molecular dynamics simulations were utilized to better understand the influence of AM structure on lipid properties and potential liposomal stabilization. Results indicate that both hydrophobic domain structure and PEG density can be utilized to fine-tune liposome properties for the desired application. Collectively, AMs demonstrate the potential to simultaneously stabilize and control the release profile of hydrophilic cargo.

Nanoemulsion loaded gel for topical co-delivery of clobitasol propionate and calcipotriol in psoriasis

Current work reports the development and optimization of clobitasol propionate (CP) and calcipotriol (CT) loaded nanoemulsion based gel for topical treatment of psoriasis. Components of nanoemulsion viz., oil and surfactant/co-surfactant were selected depending upon solubility and emulsification potential respectively. The optimized ratio of 5:3:2 of Capmul MCM C8 EP, Cremophor RH 40 and Labrafil 1944 CS was selected. Carbopol 980 was used as gelling agent to achieve final drug concentration of 0.05% w/w and 0.005% w/w respectively for CP and CT. HaCaT cell lines showed higher uptake of drug from nanoemulsion in correlation with the enhancement in penetration of both drugs in stratum corneum (SC) and viable layer from nanoemulsion and gel as compared to free drugs. Imiquimod induced psoriatic BALB/c mice revealed significantly higher anti-psoriatic activity of nanoemulsion gel as compared to free drugs and marketed formulation. The developed formulation showed negligible skin irritation despite increased penetration into the skin.

Biomimetic Lipid-Based Nanosystems for Enhanced Dermal Delivery of Drugs and Bioactive Agents

Clinical utility of conventional oral therapies is limited by their inability to deliver therapeutic molecules at the local or targeted site, causing a variety of side effects. Transdermal delivery has made a significant contribution in the management of skin diseases with enhanced therapeutic activities over the past two decades. In the modern era, various biomimetic and biocompatible polymer-lipid hybrid systems have been used to augment the transdermal delivery of therapeutics such as dermal patches, topical gels, iontophoresis, electroporation, sonophoresis, thermal ablation, microneedles, cavitational ultrasound, and nano or microlipid vesicular systems. Nevertheless, the stratum corneum still represents the main barrier to the delivery of vesicles into the skin. Lipid based formulations applied to the skin are at the center of attention and are anticipated to be increasingly functional as the skin offers many advantages for the direction of such systems. Accordingly, this review provides an overview of the development of conventional to advanced biomimetic lipid vesicles for skin delivery of a variety of therapeutics, with special emphasis on recent developments in this field including the development of transferosomes, niosomes, aquasomes, cubosomes, and other new generation lipoidal carriers.

Serum pharmacokinetics of choline, trimethylamine, and trimethylamine-N-oxide after oral gavage of phosphatidylcholines with different fatty acid compositions in mice

Little is known about the pharmacokinetics of phosphatidylcholine (PC)-derived choline, trimethylamine (TMA), and trimethylamine-N-oxide (TMAO). We therefore aim to investigate serum choline, TMA, and TMAO pharmacokinetics following different PCs gavage and compare the difference between PC emulsions and liposomes (SOL). Serum choline, TMA, and TMAO levels were measured after orally gavaged egg yolk PC emulsion (EGE), squid PC emulsion (SQE), soybean PC emulsion (SOE), and SOL in fasted mice. Time to reach peak concentration (Tmax) and productions for TMA and TMAO were more slow and less in SQE group compared with EGE and SOE groups. Tmax for choline, TMA, and TMAO prolonged, and the productions of them were significantly declined in SOL group compared to SOE group. These findings indicated that marine source squid PC could counter-regulate the potential risks of TMAO generation, and the use of liposome as the form of PC supplementary may eliminate TMAO production.

Physical and biological characterization of sericin-loaded copolymer liposomes stabilized by polyvinyl alcohol

Sericin protein (SP) is widely used as a nutrient biomaterial for biomedical and cosmeceutical applications although it shows low stability to heat and light. To overcome these problems and add value to wastewater from the silk industry, sericin protein was recovered as sericin-loaded copolymer-liposomes (SP-PVA-LP), prepared through thin film hydration. The size and morphology of the liposomes were investigated using dynamic light scattering (DLS), and electron microscopy (SEM and TEM). The particle size, liposome surface morphology and encapsulation efficiency of SP were dependent on PVA concentration. The hydrodynamic size of the nanoparticles was between 200 and 400nm, with the degree of negative charge contingent on sericin loading. SEM and TEM images confirmed the mono-dispersity, and spherical nature of the particles, with FTIR measurements confirming the presence of surface bound PVA. Exposure of liposomes to 500ppm sericin highlighted a dependence of encapsulation efficiency on PVA content; 2% surface PVA proved the optimal level for sericin loading. Cytotoxicity and viability assays revealed that SP-loaded surface modified liposomes promote cellular attachment and proliferation of human skin fibroblasts without adverse toxic effects. Surface modified copolymer liposomes show high performance in maintaining structural stability, and promoting enhancements in the solubility and bio-viability of sericin. Taken together, these biocompatible constructs allow for effective controlled release, augmenting sericin activity and resulting in effective drug delivery systems.

Glycerosomes: Use of hydrogenated soy phosphatidylcholine mixture and its effect on vesicle features and diclofenac skin penetration

In this work, diclofenac was encapsulated, as sodium salt, in glycerosomes containing 10, 20 or 30% of glycerol in the water phase with the aim to ameliorate its topical efficacy. Taking into account previous findings, glycerosome formulation was modified, in terms of economic suitability, using a cheap and commercially available mixture of hydrogenated soy phosphatidylcholine (P90H). P90H glycerosomes were spherical and multilamellar; photon correlation spectroscopy showed that obtained vesicles were ∼131nm, slightly larger and more polydispersed than those made with dipalmitoylphosphatidylcholine (DPPC) but, surprisingly, they were able to ameliorate the local delivery of diclofenac, which was improved with respect to previous findings, in particular using glycerosomes containing high amount of glycerol (20 and 30%). Finally, this drug delivery system showed a high in vitro biocompatibility toward human keratinocytes.

The Effect of Particle Size on the Deposition of Solid Lipid Nanoparticles in Different Skin Layers: A Histological Study

PURPOSE

In the present study the effect of particle size, as a substantial parameters in skin penetration, on the deposition depth and rate of SLNs in different layers of skin was explored.

METHODS

SLNs in different particle size ranges (80, 333 and 971 nm) made of Precirol as solid lipid were prepared using hot melt homogenization technique and pigmented by Rhodamine B to be able to be tracked in the skin under inspection of fluorescent microscopy. After 0.5 h, 3 h, 6 h and 24 h of SLNs administration on rat skin, animals were sacrificed and exercised skins were sliced by a freeze microtome. SLNs were monitored in the skin structure under fluorescence microscope.

RESULTS

The size of SLNs played a crucial role in the penetration to deep skin layers. The sub100 nm size range of SLNs showed the most promising skin penetration rate and depth mainly via hair follicles.

CONCLUSION

The results of the present study indicated that the selection of an appropriate size of particles may be a valuable factor impacting the therapeutic outcomes of dermal drug administration.

Exploring the use of nanocarrier systems to deliver the magical molecule; Curcumin and its derivatives

Curcumin and its derivatives; curcuminoids have been proven as potential remedies in different diseases. However, their delivery carries several challenges owing to their poor aqueous solubility, photodegradation, chemical instability, poor bioavailability and rapid metabolism. This review explores and criticizes the numerous attempts that were adopted through the years to entrap/encapsulate this valuable drug in nanocarriers aiming to reach its most appropriate and successful delivery system.

A Comparison of the Penetration and Permeation of Caffeine into and through Human Epidermis after Application in Various Vesicle Formulations

<b><i>Background/Aims:</i></b> A range of vesicles is now widely used to carry various solutes into and through the epidermis. These usually have the active solute encapsulated within and may be modified to confer flexibility and skin penetration enhancement. Here, we compared the ability of five different vesicle systems to deliver a model hydrophilic drug, caffeine, into and through excised human skin. <b><i>Methods:</i></b> In addition to lipids, the vesicle excipients included eucalyptol or oleic acid as penetration enhancers, and decyl polyglucoside as a non-ionic surfactant. Vesicle particle sizes ranged between 135 and 158 nm, and caffeine encapsulation efficiencies were between 46 and 66%. Caffeine penetration and permeation were measured using high-performance liquid chromatography. <b><i>Results:</i></b> We found that niosomes, which are liposomes containing a non-ionic surfactant, and transferosomes (ultraflexible vesicles) showed significantly greater penetration into the skin and permeation across the stratum corneum. Significant enhancement of caffeine penetration into hair follicles was found for transferosomes and those liposomes containing oleic acid. <b><i>Conclusions:</i></b> We conclude that targeted delivery of the hydrophilic drug caffeine into the skin compartments can be modified using optimized vesicular formulations.