Study of magnetic silk fibroin nanoparticles for massage-like transdermal drug delivery

Silk Nanocarrier with Tunable Size to Improve Transdermal Capacity for Hydrophilic and Hydrophobic Drugs

Transdermal drug delivery is an attractive option for multiple disease therapies as it reduces adverse reactions and improves patient compliance. Water-dispersible β-sheet rich silk nanofiber carriers have hydrophobic properties that benefit transdermal delivery but still show inferior transdermal capacities. Thus, hydrophobic silk nanofibers were fabricated to fine-tune their size and endow them with desirable transdermal delivery capacities. Silk nanocarrier length was shortened from 2000 nm to approximately 40 nm after ultrasonic treatment. In vitro human skin and in vivo animal studies revealed different transdermal behaviors for silk nanocarriers at different nanosizes. Silk nanocarriers passed slowly through the corneum without destroying the corneum structure. Improved transdermal capacity was achieved for smaller size carriers. Both hydrophilic and hydrophobic drugs could be loaded onto silk nanocarriers, suggesting a promising future for different disease therapies. No cytotoxicity and skin irritation were identified for silk nanocarriers, which strengthened their superiority as transdermal carriers. Therefore, silk nanocarriers <100 nm may promote the percutaneous absorption of active cargos for disease therapy and cosmetic applications.

Silk peptide-hyaluronic acid based nanogels for the enhancement of the topical administration of curcumin

The present study focused on the development of Cur-loaded SOHA nanogels (Cur-SHNGs) to enhance the topical administration of Cur. The physiochemical properties of Cur-SHNGs were characterized. Results showed that the morphology of the Cur-SHNGs was spherical, the average size was 171.37 nm with a zeta potential of −13.23 mV. Skin permeation experiments were carried out using the diffusion cell systems. It was found that the skin retention of Cur-SHNGs was significantly improved since it showed the best retention value (0.66 ± 0.17 μg/cm²). In addition, the hematoxylin and eosin staining showed that the Cur-SHNGs improved transdermal drug delivery by altering the skin microstructure. Fluorescence imaging indicated that Cur-SHNGs could effectively deliver the drug to the deeper layers of the skin. Additionally, Cur-SHNGs showed significant analgesic and anti-inflammatory activity with no skin irritation. Taken together, Cur-SHNGs could be effectively used for the topical delivery of therapeutic drugs.

Nanoparticle and Nanostructure Synthesis and Controlled Growth Methods

Nanomaterials are materials with one or more nanoscale dimensions (internal or external) (i.e., 1 to 100 nm). The nanomaterial shape, size, porosity, surface chemistry, and composition are controlled at the nanoscale, and this offers interesting properties compared with bulk materials. This review describes how nanomaterials are classified, their fabrication, functionalization techniques, and growth-controlled mechanisms. First, the history of nanomaterials is summarized and then the different classification methods, based on their dimensionality (0-3D), composition (carbon, inorganic, organic, and hybrids), origin (natural, incidental, engineered, bioinspired), crystal phase (single phase, multiphase), and dispersion state (dispersed or aggregated), are presented. Then, the synthesis methods are discussed and classified in function of the starting material (bottom-up and top-down), reaction phase (gas, plasma, liquid, and solid), and nature of the dispersing forces (mechanical, physical, chemical, physicochemical, and biological). Finally, the challenges in synthesizing nanomaterials for research and commercial use are highlighted.

How physical techniques improve the transdermal permeation of therapeutics: A review

BACKGROUND

Transdermal delivery is very important in pharmaceutics. However, the barrier function of the stratum corneum hinders drugs absorption. How to improve transdermal delivery efficiency is a hot topic. The key advantages of physical technologies are their wide application for the delivery of previously nonappropriate transdermal drugs, such as proteins, peptides, and hydrophilic drugs. Based on the improved permeation of drugs delivered via multiple physical techniques, many more diseases may be treated, and transdermal vaccinations become possible. However, their wider application depends on the related convenient and portable devices. Combined products comprising medicine and devices represent future commercial directions of artificial intelligence and 3D printing.

METHODS

A comprehensive search about transdermal delivery assisted by physical techniques has been carried out on Web of Science, EMBASE database, PubMed, Wanfang Database, China National Knowledge Infrastructure, and Cochrane Library. The search identified and retrieved the study describing multiple physical technologies to promote transdermal penetration.

RESULTS

Physical technologies, including microneedles, lasers, iontophoresis, sonophoresis, electroporation, magnetophoresis, and microwaves, are summarized and compared. The characteristics, mechanism, advantages and disadvantages of physical techniques are clarified. The individual or combined applicable examples of physical techniques to improve transdermal delivery are summarized.

CONCLUSION

This review will provide more useful guidance for efficient transdermal delivery. More therapeutic agents by transdermal routes become possible with the assistance of various physical techniques.

The Factors Determining the Skin Penetration and Cellular Uptake of Nanocarriers: New Hope for Clinical Development

The skin provides a protective barrier against toxic environments and also offers a valuable route for topical drug delivery. The stratum corneum (SC) is the outermost layer of the skin and serves as the major barrier to chemical transfer through the skin. The human skin barrier is particularly difficult to overcome because of the complex composition and structure of the SC. Nanoparticulate carriers have gained widespread attention in topical drug delivery due to their tunable and versatile properties. The present review summarizes the main factors involved in skin penetration of nanocarriers containing the drug. Employment of nanotechnology in topical delivery has grown progressively during recent years; however, it is important to monitor the skin penetration of nanocarriers prior to their use to avoid possible toxic effects. Nanocarriers can act as a means to increase skin permeation of drugs by supporting direct interaction with the SC and increasing the period of permanence on the skin. Skin penetration is influenced by the physicochemical characteristics of nanocarriers such as composition, size, shape, surface chemistry, as well as skin features. Considering that the target of topical systems based on nanocarriers is the penetration of therapeutic agents in the skin layers, so a detailed understanding of the factors influencing skin permeability of nanocarriers is essential for safe and efficient therapeutic applications.

Systemic and Local Silk-Based Drug Delivery Systems for Cancer Therapy

For years, surgery, radiotherapy, and chemotherapy have been the gold standards to treat cancer, although continuing research has sought a more effective approach. While advances can be seen in the development of anticancer drugs, the tools that can improve their delivery remain a challenge. As anticancer drugs can affect the entire body, the control of their distribution is desirable to prevent systemic toxicity. The application of a suitable drug delivery platform may resolve this problem. Among other materials, silks offer many advantageous properties, including biodegradability, biocompatibility, and the possibility of obtaining a variety of morphological structures. These characteristics allow the exploration of silk for biomedical applications and as a platform for drug delivery. We have reviewed silk structures that can be used for local and systemic drug delivery for use in cancer therapy. After a short description of the most studied silks, we discuss the advantages of using silk for drug delivery. The tables summarize the descriptions of silk structures for the local and systemic transport of anticancer drugs. The most popular techniques for silk particle preparation are presented. Further prospects for using silk as a drug carrier are considered. The application of various silk biomaterials can improve cancer treatment by the controllable delivery of chemotherapeutics, immunotherapeutics, photosensitizers, hormones, nucleotherapeutics, targeted therapeutics (e.g., kinase inhibitors), and inorganic nanoparticles, among others.

Hyperthermia treatment of cancer cells by the application of targeted silk/iron oxide composite spheres

Magnetic iron oxide nanoparticles (IONPs) are one of the most extensively studied materials for theranostic applications. IONPs can be used for magnetic resonance imaging (MRI), delivery of therapeutics, and hyperthermia treatment. Silk is a biocompatible material and can be used for biomedical applications. Previously, we produced spheres made of H2.1MS1 bioengineered silk that specifically carried a drug to the Her2-overexpressing cancer cells. To confer biocompatibility and targeting properties to IONPs, we blended these particles with bioengineered spider silks. Three bioengineered silks (MS1Fe1, MS1Fe2, and MS1Fe1Fe2) functionalized with the adhesion peptides F1 and F2, were constructed and investigated to form the composite spheres with IONPs carrying a positive or negative charge. Due to its highest IONP content, MS1Fe1 silk was used to produce spheres from the H2.1MS1:MS1Fe silk blend to obtain a carrier with cell-targeting properties. Composite H2.1MS1:MS1Fe1/IONP spheres made of silks blended at different ratios were obtained. Although the increased content of MS1Fe1 silk in particles resulted in an increased affinity of the spheres to IONPs, it decreased the binding of the composite particles to cancer cells. The H2.1MS1:MS1Fe1 particles prepared at a ratio of 8:2 and loaded with IONPs exhibited the ability to bind to the targeted cancer cells similar to the control spheres without IONPs. Moreover, when exposed to the alternating magnetic field, these particles generated 2.5 times higher heat. They caused an almost three times higher percentage of apoptosis in cancer cells than the control particles. The blending of silks enabled the generation of cancer-targeting spheres with a high affinity for iron oxide nanoparticles, which can be used for anti-cancer hyperthermia therapy.

Silk Particles as Carriers of Therapeutic Molecules for Cancer Treatment

Although progress is observed in cancer treatment, this disease continues to be the second leading cause of death worldwide. The current understanding of cancer indicates that treating cancer should not be limited to killing cancer cells alone, but that the target is the complex tumor microenvironment (TME). The application of nanoparticle-based drug delivery systems (DDS) can not only target cancer cells and TME, but also simultaneously resolve the severe side effects of various cancer treatment approaches, leading to more effective, precise, and less invasive therapy. Nanoparticles based on proteins derived from silkworms' cocoons (like silk fibroin and sericins) and silk proteins from spiders (spidroins) are intensively explored not only in the oncology field. This natural-derived material offer biocompatibility, biodegradability, and simplicity of preparation methods. The protein-based material can be tailored for size, stability, drug loading/release kinetics, and functionalized with targeting ligands. This review summarizes the current status of drug delivery systems' development based on proteins derived from silk fibroin, sericins, and spidroins, which application is focused on systemic cancer treatment. The nanoparticles that deliver chemotherapeutics, nucleic acid-based therapeutics, natural-derived agents, therapeutic proteins or peptides, inorganic compounds, as well as photosensitive molecules, are introduced.

Impact of the magnetic field on 3T3-E1 preosteoblasts inside SMART silk fibroin-based scaffolds decorated with magnetic nanoparticles

This paper reports the impact of the magnetic field on 3T3-E1 preosteoblasts within silk-fibroin scaffolds decorated with magnetic nanoparticles. Scaffolds were prepared from silk fibroin and poly(2-hydroxyethyl methacrylate) template in which magnetite nanoparticles were embedded. The presence of the magnetite specific peaks within scaffolds compositions was evidenced by RAMAN analysis. Structural investigation was done by XRD analysis and morphological information including internal structure was obtained through SEM analysis. Geometrical evaluation (size and shape), crystalline structure of magnetic nanoparticles and the morphology of the silk fibroin scaffolds were investigated by HR-TEM. Magnetic nanoparticles were distributed within scaffolds structure. Biomineralization of hydroxyapatite on silk fibroin scaffolds with and without magnetic nanoparticles was investigated by an alternate soaking process. SEM images showed that the magnetic scaffolds were covered in an almost continuously film, which has a phase with nanostructured characteristics. This phase, which has as main components Ca and P, is made of lamellar formations. The design of an original magnetic 3D cell culture setup allowed us to observe cellular modifications under the exposure to magnetic field in the presence of magnetic silk fibroin biomaterials. The cellular proliferation potential of 3T3-E1 cell line was found increased under the magnetic field, especially in the presence of the magnetite nanoparticles. In addition, we showed that the low static magnetic field positively impacts on the osteogenic differentiation potential of the cells inside the biomimetic magnetic scaffolds.

Composite spheres made of bioengineered spider silk and iron oxide nanoparticles for theranostics applications

Bioengineered spider silk is a biomaterial that has exquisite mechanical properties, biocompatibility, and biodegradability. Iron oxide nanoparticles can be applied for the detection and analysis of biomolecules, target drug delivery, as MRI contrast agents and as therapeutic agents for hyperthermia-based cancer treatments. In this study, we investigated three bioengineered silks, MS1, MS2 and EMS2, and their potential to form a composite material with magnetic iron oxide nanoparticles (IONPs). The presence of IONPs did not impede the self-assembly properties of MS1, MS2, and EMS2 silks, and spheres formed. The EMS2 spheres had the highest content of IONPs, and the presence of magnetite IONPs in these carriers was confirmed by several methods such as SEM, EDXS, SQUID, MIP-OES and zeta potential measurement. The interaction of EMS2 and IONPs did not modify the superparamagnetic properties of the IONPs, but it influenced the secondary structure of the spheres. The composite particles exhibited a more than two-fold higher loading efficiency for doxorubicin than the plain EMS2 spheres. For both the EMS2 and EMS2/IONP spheres, the drug revealed a pH-dependent release profile with advantageous kinetics for carriers made of the composite material. The composite spheres can be potentially applied for a combined cancer treatment via hyperthermia and drug delivery.

Transdermal delivery of 40-nm silk fibroin nanoparticles

Transdermal administration of drugs improves their bioavailability and is capable of systemic and local treatment. To improve the skin permeability of drugs, nano-sized systems have attracted attention as drug carriers for transdermal drug delivery system. We considered that silk fibroin composed of a crystalline region with many hydrophobic amino acids and an amorphous region with many hydrophilic amino acids was useful as a carrier for transdermal administration of a drug because of the balance between hydrophilicity and hydrophobicity. In this study, silk fibroin nanoparticles with mean volume diameters of 42.3 nm were successfully prepared, and storage stability was confirmed by storing the nanoparticle suspension at 4, 32, and 37 °C for a week. At any storage temperature, the mean volume diameter and standard deviation were stable. The polydispersity indexes were 0.19-0.23, and no specific trends were observed. Then, to investigate the transdermal delivery route of the silk fibroin nanoparticles, skin permeability in vivo was evaluated using mice. Six hours after administration, fluorescent substances were observed in the dermis in addition to the stratum corneum, hair follicles and the epidermis around them. This result indicated that fibroin nanoparticles with the mean volume diameter of 40-nm penetrated the stratum corneum and was delivered deep into the skin. Therefore, it was suggested that small nanoparticles prepared using silk fibroin are useful for drug delivery to the dermis.

Nanoparticles as Carriers of Proteins, Peptides and Other Therapeutic Molecules

Nanoparticles have many applications both in industry and medicine. Depending upon their physical and chemical properties, they can be used as carriers of therapeutic molecules or as therapeutics. Nanoparticles are made of synthetic or natural polymers, lipids or metals. Their use allows for faster transport to the place of action, thus prolonging its presence in the body and limiting side effects. In addition, the use of such a drug delivery system protects the drug from rapid disintegration and elimination from the body. In recent years, the use of proteins and peptides as therapeutic molecules has grown significantly. Unfortunately, proteins are subject to enzymatic digestion and can cause unwanted immune response beyond therapeutic action. The use of drug carriers can minimize undesirable side effects and reduce the dose of medication needed to achieve the therapeutic effect. The current study presents the use of several selected drug delivery systems for the delivery of proteins, peptides and other therapeutic molecules.

Influence of medium viscosity and intracellular environment on the magnetization of superparamagnetic nanoparticles in silk fibroin solutions and 3T3 mouse fibroblast cell cultures

Biomedical applications based on the magnetic properties of superparamagnetic iron oxide nanoparticles (SPIONs) may be altered by the mechanical attachment or cellular uptake of these nanoparticles. When nanoparticles interact with living cells, they are captured and internalized into intracellular compartments. Consequently, the magnetic behavior of the nanoparticles is modified. In this paper, we investigated the change in the magnetic response of 14 nm magnetic nanoparticles (Fe₃O₄) in different solutions, both as a stable liquid suspension (one of them mimicking the cellular cytoplasm) and when associated with cells. The field-dependent magnetization curves from inert fluids and cell cultures were determined by using an alternating gradient magnetometer, MicroMagTM 2900. The equipment was adapted to measure liquid samples because it was originally designed only for solids. In order to achieve this goal, custom sample holders were manufactured. Likewise, the nuclear magnetic relaxation dispersion profiles for the inert fluid were also measured by fast field cycling nuclear magnetic relaxation relaxometry. The results show that SPION magnetization in inert fluids was affected by the carrier liquid viscosity and the concentration. In cell cultures, the mechanical attachment or confinement of the SPIONs inside the cells accounted for the change in the dynamic magnetic behavior of the nanoparticles. Nevertheless, the magnetization value in the cell cultures was slightly lower than that of the fluid simulating the viscosity of cytoplasm, suggesting that magnetization loss was not only due to medium viscosity but also to a reduction in the mechanical degrees of freedom of SPIONs rotation and translation inside cells. The findings presented here provide information on the loss of magnetic properties when nanoparticles are suspended in viscous fluids or internalized in cells. This information could be exploited to improve biomedical applications based on magnetic properties such as magnetic hyperthermia, contrast agents and drug delivery.

Solution-enhanced dispersion by supercritical fluids: an ecofriendly nanonization approach for processing biomaterials and pharmaceutical compounds

In recent years, the supercritical fluid (SCF) technology has attracted enormous interest from researchers over the traditional pharmaceutical manufacturing strategies due to the environmentally benign nature and economically promising character of SCFs. Among all the SCF-assisted processes for particle formation, the solution-enhanced dispersion by supercritical fluids (SEDS) process is perhaps one of the most efficient methods to fabricate the biomaterials and pharmaceutical compounds at an arbitrary gauge, ranging from micro- to nanoscale. The resultant miniature-sized particles from the SEDS process offer enhanced features concerning their physical attributes such as bioavailability enhancement due to their high surface area. First, we provide a brief description of SCFs and their behavior as an anti-solvent in SCF-assisted processing. Then, we aim to give a brief overview of the SEDS process as well as its modified prototypes, highlighting the pros and cons of the particular modification. We then emphasize the effects of various processing constraints such as temperature, pressure, SCF as well as organic solvents (if used) and their flow rates, and the concentration of drug/polymer, among others, on particle formation with respect to the particle size distribution, precipitation yield, and morphologic attributes. Next, we aim to systematically discuss the application of the SEDS technique in producing therapeutic nano-sized formulations by operating the drugs alone or in combination with the biodegradable polymers for the application focusing oral, pulmonary, and transdermal as well as implantable delivery with a set of examples. We finally summarize with perspectives.

Supercritical carbon dioxide-based technologies for the production of drug nanoparticles/nanocrystals - A comprehensive review

Low drug bioavailability, which is mostly a result of poor aqueous drug solubilities and of inadequate drug dissolution rates, is one of the most significant challenges that pharmaceutical companies are currently facing, since this may limit the therapeutic efficacy of marketed drugs, or even result in the discard of potential highly effective drug candidates during developmental stages. Two of the main approaches that have been implemented in recent years to overcome poor drug solubility/dissolution issues have frequently involved drug particle size reduction (i.e., micronization/nanonization) and/or the modification of some of the physicochemical and structural properties of poorly water soluble drugs. A large number of particle engineering methodologies have been developed, tested, and applied in the synthesis and control of particle size/particle-size distributions, crystallinities, and polymorphic purities of drug micro- and nano-particles/crystals. In recent years pharmaceutical processing using supercritical fluids (SCF), in general, and supercritical carbon dioxide (scCO₂), in particular, have attracted a great attention from the pharmaceutical industry. This is mostly due to the several well-known advantageous technical features of these processes, as well as to other increasingly important subjects for the pharmaceutical industry, namely their "green", sustainable, safe and "environmentally-friendly" intrinsic characteristics. In this work, it is presented a comprehensive state-of-the-art review on scCO₂-based processes focused on the formation and on the control of the physicochemical, structural and morphological properties of amorphous/crystalline pure drug nanoparticles. It is presented and discussed the most relevant scCO₂, scCO₂-based fluids and drug physicochemical properties that are pertinent for the development of successful pharmaceutical products, namely those that are critical in the selection of an adequate scCO₂-based method to produce pure drug nanoparticles/nanocrystals. scCO₂-based nanoparticle formation methodologies are classified in three main families, and in terms of the most important role played by scCO₂ in particle formation processes: as a solvent; as an antisolvent or a co-antisolvent; and as a "high mobility" additive (a solute, a co-solute, or a co-solvent). Specific particle formation methods belonging to each one of these families are presented, discussed and compared. Some selected amorphous/crystalline drug nanoparticles that were prepared by these methods are compiled and presented, namely those studied in the last 10-15 years. A special emphasis is given to the formation of drug cocrystals. It is also discussed the fundamental knowledge and the main mechanisms in which the scCO₂-based particle formation methods rely on, as well as the current status and urgent needs in terms of reliable experimental data and of robust modeling approaches. Other addressed and discussed topics include the currently available and the most adequate physicochemical, morphological and biological characterization methods required for pure drug nanoparticles/nanocrystals, some of the current nanometrology and regulatory issues associated to the use of these methods, as well as some scale-up, post-processing and pharmaceutical regulatory subjects related to the industrial implementation of these scCO₂-based processes. Finally, it is also discussed the current status of these techniques, as well as their future major perspectives and opportunities for industrial implementation in the upcoming years.

Supercritical carbon dioxide-developed silk fibroin nanoplatform for smart colon cancer therapy

Purpose

To deliver insoluble natural compounds into colon cancer cells in a controlled fashion.

Materials and methods

Curcumin (CM)–silk fibroin (SF) nanoparticles (NPs) were prepared by solution-enhanced dispersion by supercritical CO₂ (SEDS) (20 MPa pressure, 1:2 CM:SF ratio, 1% concentration), and their physicochemical properties, intracellular uptake efficiency, in vitro anticancer effect, toxicity, and mechanisms were evaluated and analyzed.

Results

CM-SF NPs (<100 nm) with controllable particle size were prepared by SEDS. CM-SF NPs had a time-dependent intracellular uptake ability, which led to an improved inhibition effect on colon cancer cells. Interestingly, the anticancer effect of CM-SF NPs was improved, while the side effect on normal human colon mucosal epithelial cells was reduced by a concentration of ~10 μg/mL. The anticancer mechanism involves cell-cycle arrest in the G₀/G₁ and G₂/M phases in association with inducing apoptotic cells.

Conclusion

The natural compound-loaded SF nanoplatform prepared by SEDS indicates promising colon cancer-therapy potential.

Getting Drugs Across Biological Barriers

The delivery of drugs to a target site frequently involves crossing biological barriers. The degree and nature of the impediment to flux, as well as the potential approaches to overcoming it, depend on the tissue, the drug, and numerous other factors. Here an overview of approaches that have been taken to crossing biological barriers is presented, with special attention to transdermal drug delivery. Technology and knowledge pertaining to addressing these issues in a variety of organs could have a significant clinical impact.

Supercritical Fluid Technology: An Emphasis on Drug Delivery and Related Biomedical Applications

During the past few decades, supercritical fluid (SCF) has emerged as an effective alternative for many traditional pharmaceutical manufacturing processes. Operating active pharmaceutical ingredients (APIs) alone or in combination with various biodegradable polymeric carriers in high-pressure conditions provides enhanced features with respect to their physical properties such as bioavailability enhancement, is of relevance to the application of SCF in the pharmaceutical industry. Herein, recent advances in drug delivery systems manufactured using the SCF technology are reviewed. We provide a brief description of the history, principle, and various preparation methods involved in the SCF technology. Next, we aim to give a brief overview, which provides an emphasis and discussion of recent reports using supercritical carbon dioxide (SC-CO2 ) for fabrication of polymeric carriers, for applications in areas related to drug delivery, tissue engineering, bio-imaging, and other biomedical applications. We finally summarize with perspectives.

Investigation of silk fibroin nanoparticle-decorated poly(l-lactic acid) composite scaffolds for osteoblast growth and differentiation

Attempts to reflect the physiology of organs is quite an intricacy during the tissue engineering process. An ideal scaffold and its surface topography can address and manipulate the cell behavior during the regeneration of targeted tissue, affecting the cell growth and differentiation significantly. Herein, silk fibroin (SF) nanoparticles were incorporated into poly(l-lactic acid) (PLLA) to prepare composite scaffolds via phase-inversion technique using supercritical carbon dioxide (SC-CO2). The SF nanoparticle core increased the surface roughness and hydrophilicity of the PLLA scaffolds, leading to a high affinity for albumin attachment. The in vitro cytotoxicity test of SF/PLLA scaffolds in L929 mouse fibroblast cells indicated good biocompatibility. Then, the in vitro interplay between mouse preosteoblast cell (MC3T3-E1) and various topological structures and biochemical cues were evaluated. The cell adhesion, proliferation, osteogenic differentiation and their relationship with the structures as well as SF content were explored. The SF/PLLA weight ratio (2:8) significantly affected the MC3T3-E1 cells by improving the expression of key players in the regulation of bone formation, ie, alkaline phosphatase (ALP), osteocalcin (OC) and collagen 1 (COL-1). These results suggest not only the importance of surface topography and biochemical cues but also the potential of applying SF/PLLA composite scaffolds as biomaterials in bone tissue engineering.

Improved skin permeation of methotrexate via nanosized ultradeformable liposomes

The aim of this study is to investigate methotrexate-entrapped ultradeformable liposomes (MTX-UDLs) for potential transdermal application. MTX-UDLs were prepared by extrusion method with phosphatidylcholine as a bilayer matrix and sodium cholate or Tween 80 as an edge activator. The physicochemical properties of MTX-UDLs were determined in terms of particle size, polydispersity index, zeta potential, and entrapment efficiency. The deformability of MTX-UDLs was compared with that of methotrexate-entrapped conventional liposomes (MTX-CLs) using a steel pressure filter device. The skin permeation of MTX-UDLs was investigated using Franz diffusion cell, and the skin penetration depth of rhodamine 6G-entrapped UDLs was determined by confocal laser scanning microscopy. MTX-UDLs showed a narrow size distribution, with the particle size of ~100 nm. The deformability of MTX-UDLs was two to five times greater than that of MTX-CLs. The skin permeation of MTX-UDLs was significantly improved compared with MTX-CLs and free MTX solution. The optimized UDLs (phosphatidylcholine: Tween 80 =7:3, w/w) showed a higher fluorescence intensity than conventional liposomes at every increment of skin depth. Thus, the optimized UDLs could be promising nanocarriers for systemic delivery of MTX across skin.