Iontophoresis-stimulated silk fibroin films as a peptide delivery system for wound healing

Recent advances in cutaneous drug delivery by iontophoresis

INTRODUCTION

Iontophoresis has been extensively studied for topical and transdermal drug delivery to stimulate the absorption of molecules that would hardly pass through the outermost layer of the skin passively. Recent research has focused on its combination with nanoparticle-based systems or microneedles to expand its therapeutic applications.

AREAS COVERED

This review explores the fundamental principles of iontophoresis, focusing on key factors influencing its drug transport mechanisms, and provides a discussion of the field's current state. A comprehensive analysis of articles published or available online in 2024 was conducted, categorizing studies by their application areas, drug delivery systems, iontophoretic conditions, and experimental limitations.

EXPERT OPINION

The findings reveal a recent focus on wound healing and skin repair, and advancements in treating inflammation, pain, and skin cancer. Market translation requires standardized experimental protocols, particularly for iontophoretic parameters and preclinical models, along with the development of cost-effective commercial devices. Additionally, while advancements in cutaneous drug delivery have increasingly benefited from machine learning approaches, their application to iontophoresis remains underexplored. With the growing interest in associating iontophoresis with the Internet of Things, such an integration, if combined with AI tools, could offer promising opportunities for personalized, real-time treatments in modern dermatology, and therapeutic systems.

Iontophoresis-driven alterations in nanoparticle uptake pathway and intracellular trafficking in carcinoma skin cancer cells

Effective treatment of squamous cell carcinoma (SCC) poses challenges due to intrinsic drug resistance and limited drug penetration into tumor cells. Nanoparticle-based drug delivery systems have emerged as a promising approach to enhance therapeutic efficacy; however, they often face hurdles such as inadequate cellular uptake and rapid lysosomal degradation. This study explores the potential of iontophoresis to augment the efficacy of liposome and immunoliposome-based drug delivery systems for SCC treatment. The study assessed iontophoresis effects on SCC cell line (A431) viability, nanoparticle uptake dynamics, and intracellular distribution patterns. Specific inhibitors were employed to delineate cellular internalization pathways, while fluorescence microscopy and immunohistochemistry examined changes in EGFR expression and lysosomal activity. Results demonstrated that iontophoresis significantly increased cellular uptake of liposomes and immunoliposomes, achieving approximately 50 % uptake compared to 10 % with passive treatment. This enhancement correlated with modifications in endocytic pathways, favoring macropinocytosis and caveolin-mediated endocytosis for liposomes, and macropinocytosis and clathrin-mediated pathways for immunoliposomes. Moreover, iontophoresis induced alterations in EGFR distribution and triggered syncytium-like cellular clustering. It also attenuated lysosomal activity, thereby reducing nanoparticle degradation and prolonging intracellular retention of therapeutic agents. These findings underscore the role of iontophoresis in modulating nanoparticle internalization pathways, offering insights that could advance targeted drug delivery strategies and mitigate therapeutic resistance in SCC and other malignancies.

Biomedical applications ofBombyx morisilk in skin regeneration and cutaneous wound healing

A mere glance at the foundation of the sericulture industry to produce silk and the consequent establishment of the Silk Road to transport it; elucidates the significant role that this material has played in human history. Owing to its exceptional robustness, silk was introduced into medicine as a surgical suture approximately two millennia ago. During the last decades, silk has garnered attention as a possible source of biological-based materials that can be effectively used in regenerative medicine. Silk's unique characteristics, like its low immunogenicity, suitable adhesive properties, exceptional tensile strength, perfect hemostatic properties, adequate permeability to oxygen and water, resistance to microbial colonization, and most importantly, excellent biodegradability; make it an outstanding choice for biomedical applications. Although there are many different types of silk in nature,Bombyx mori(B. mori) silk accounts for about 90% of global production and is the most thoroughly investigated and the most commonly used. Silk fibroin (SF) and silk sericin (SS) are the two main protein constituents of silk. SF has been manufactured in various morphologic forms (e.g. hydrogels, sponges, films, etc) and has been widely used in the biomedical field, especially as a scaffold in tissue engineering. Similarly, SS has demonstrated a vast potential as a suitable biomaterial in tissue engineering and regenerative medicine. Initial studies on SF and SS as wound dressings have shown encouraging results. This review aims to comprehensively discuss the potential role of silk proteins in refining wound healing and skin regeneration.

Silk-fibroin chitosan film for palatal wounds: Material development, in vitro study, and pilot clinical trial

BACKGROUND

In the present study, we aim to assess a novel silk-fibroin (SF) chitosan (CH) film to treat oral mucosa wounds.

METHODS

The SF/CH films, sterilized with 130 Gy in a gamma cell, were subjected to tests for thickness, water vapor permeability, tensile strength, elongation, and swelling as well as scanning electron microscopy. Additionally, in vitro cytotoxicity and genotoxicity were evaluated using human epidermal keratinocytes, human foreskin fibroblasts, and human gingival fibroblasts. A pilot clinical trial was conducted with 10 patients who underwent a free gingival graft procedure for socket preservation. The palatal wound healing was evaluated through clinical, patient-centered, immunological, and histological assessments.

RESULTS

The SF/CH film exhibited a thickness of 187.5 ± 8.0 µm and water vapor permeability of 15.87 ± 7.52 g mm m2 day-1 kPa-1, and microscopy revealed a uniformly rough surface. A flexible scaffold was observed (Young's modulus = 1.74 ± 0.90 MPa) with 1% of water absorption within 2 h. The in vitro analysis showed increased cell viability and low genotoxicity for epithelial and fibroblast cells. For the clinical assessments, wound closure was 28.06 ± 4.3mm2 and 0.95 ± 1.9mm2 after 7 and 14 days, respectively. The immunological assay exhibited a decrease in tissue inhibitor of metalloproteinase-1 (TIMP-1) (p = 0.02) and an increase in macrophage inflammatory protein-1 alpha (MIP-1α) (p = 0.008) from Day 3 to Day 7. Histology showed the absence of residual biomaterial after 12 months. Complete epithelialization was reached on Day 21, and no tissue thickness loss was observed after 90 days. Patients reported low discomfort and minimal analgesic intake.

CONCLUSION

Within the present study's limits, SF/CH film may be useful to help in the healing of wounds on the palatal mucosa. Further clinical investigations are required.

PLAIN LANGUAGE SUMMARY

This study aimed to evaluate a novel silk fibroin and chitosan film for treating palatal mucosa wounds. The films were sterilized, tested for physical properties, such as thickness, tensile strength, elongation, water vapor permeability, and swelling, and subjected to scanning electron microscopy. In vitro tests using human oral and skin cells assessed the film's toxicity. Ten patients undergoing graft-harvesting procedures received the film, and their healing was monitored clinically, immunologically, and histologically. The film demonstrated appropriate physical properties, and laboratory results indicated high cell viability and low toxicity. Clinically, the wounds demonstrated considerable closure by Day 7 and almost full closure by Day 14. Immunological assessments indicated elevation in some healing markers, and histology revealed no residual biomaterial at 12 months post treatment. Complete epithelialization occurred by Day 21, with no tissue thickness loss at 90 days, and patients reported low discomfort and minimal analgesic use. These findings suggest that the silk-fibroin/chitosan film may be beneficial for oral wound healing, warranting further clinical studies to confirm its efficacy.

Natural Protein Films from Textile Waste for Wound Healing and Wound Dressing Applications

In recent years, several studies have focused on the development of sustainable, biocompatible, and biodegradable films with potential applications in wound healing and wound dressing systems. Natural macromolecules, particularly proteins, have emerged as attractive alternatives to synthetic polymers due to their biocompatibility, biodegradability, low immunogenicity, and adaptability. Among these proteins, keratin, extracted from waste wool, and fibroin, derived from Bombyx mori cocoons, exhibit exceptional properties such as mechanical strength, cell adhesion capabilities, and suitability for various fabrication methods. These proteins can also be functionalized with antimicrobial, antioxidant, and anti-inflammatory compounds, making them highly versatile for biomedical applications. This review highlights the promising potential of keratin- and fibroin-based films as innovative platforms for wound healing, emphasizing their advantages and the prospects they offer in creating next-generation wound dressing devices.

Development of a cationic bacterial cellulose film loaded with anionic liposomes for prolonged release of oxacillin in wound dressing applications

Dressings should protect wounds, promote healing, absorb fluids, and maintain moisture. Bacterial cellulose is a biopolymer that stands out in biomaterials due to its high biocompatibility in several applications. In the area of dressings, it is already marketed as an alternative to traditional dressings. However, it lacks any intrinsic activity; among these, the need for antimicrobial activity in infected wounds stands out. We developed a cationic cellulose film by modifying cellulose with 1-(5-carboxypentyl)pyridin-1-ium bromide, enhancing its wettability (contact angle: 26.6°) and water retention capacity (2714.37 %). This modified film effectively retained oxacillin compared to the unmodified control. Liposomal encapsulation further prolonged oxacillin release up to 11 days. Both oxacillin-loaded films and liposomal formulations demonstrated antimicrobial activity against Staphylococcus aureus. Our findings demonstrate the potential of chemically modified cellulose as a platform for controlled anionic antibiotics and/or their formulations delivery in wound care.

Electrostimulable polymeric films with hyaluronic acid and lipid nanoparticles for simultaneous topical delivery of macromolecules and lipophilic drugs

This study focused on developing electrically stimulable hyaluronic acid (HA) films incorporating lipid nanoparticles (NPs) designed for the topical administration of lipophilic drugs and macromolecules. Based on beeswax and medium-chain triglycerides, NPs were successfully integrated into silk fibroin/chitosan films containing HA (NP-HA films) at a density of approximately 1011 NP/cm2, ensuring a uniform distribution. This integration resulted in a 40% increase in film roughness, a twofold decrease in Young's modulus, and enhanced film flexibility and bioadhesion work. The NP-HA films, featuring Ag/AgCl electrodes, demonstrated the capability to conduct a constant electrical current of 0.2 mA/cm2 without inducing toxicity in keratinocytes and fibroblasts during a 15-min application. Moreover, the NPs facilitated the homogeneous distribution of lipophilic drugs within the film, effectively transporting them to the skin and uniformly distributing them in the stratum corneum upon film administration. The sustained release of HA from the films, following Higuchi kinetics, did not alter the macroscopic characteristics of the film. Although anodic iontophoresis did not noticeably affect the release of HA, it did enhance its penetration into the skin. This enhancement facilitated the permeation of HA with a molecular weight (MW) of up to 2 × 105 through intercellular and transcellular routes. Confocal Raman spectroscopy provided evidence of an approximate 100% increase in the presence of HA with a MW in the range of 1.5-1.8 × 106 in the viable epidermis of human skin after only 15 min of iontophoresis applied to the films. Combining iontophoresis with NP-HA films exhibits substantial potential for noninvasive treatments focused on skin rejuvenation and wound healing.

Silk fibroin-based dressings with antibacterial and anti-inflammatory properties

Silk fibroin is a fibrillar protein obtained from arthropods such as mulberry and non-mulberry silkworms. Silk fibroin has been used as a dressing in wound treatment for its physical, chemical, mechanical, and biological properties. This systematic review analyzed studies from PubMed, Web of Science, and Scopus databases to identify the molecules preferred for functionalizing silk fibroin-based dressings and to describe their mechanisms of exhibiting anti-inflammatory and antibacterial properties. The analysis of the selected articles allowed us to classify the dressings into different conformations, such as membranes, films, hydrogels, sponges, and bioadhesives. The incorporation of various molecules, including antibiotics, natural products, peptides, nanocomposites, nanoparticles, secondary metabolites, growth factors, and cytokines, has allowed the development of dressings that promote wound healing with antibacterial and immunomodulatory properties. In addition, silk fibroin-based dressings have been established to have the potential to regenerate wounds such as venous ulcers, arterial ulcers, diabetic foot, third-degree burns, and neoplastic ulcers. Evaluation of the efficacy of silk fibroin-based dressings in tissue engineering is an area of great activity that has shown significant advances in recent years.

A comprehensive review of silk-fibroin hydrogels for cell and drug delivery applications in tissue engineering and regenerative medicine

Hydrogel scaffolds hold great promise for developing novel treatment strategies in the field of regenerative medicine. Within this context, silk fibroin (SF) has proven to be a versatile material for a wide range of tissue engineering applications owing to its structural and functional properties. In the present review, we report on the design and fabrication of different forms of SF-based scaffolds for tissue regeneration applications, particularly for skin, bone, and neural tissues. In particular, SF hydrogels have emerged as delivery systems for a wide range of bio-actives. Given the growing interest in the field, this review has a primary focus on the fabrication, characterization, and properties of SF hydrogels. We also discuss their potential for the delivery of drugs, stem cells, genes, peptides, and growth factors, including future directions in the field of SF hydrogel scaffolds.

Nanoemulsions Based on Sunflower and Rosehip Oils: The Impact of Natural and Synthetic Stabilizers on Skin Penetration and an Ex Vivo Wound Healing Model

Vegetable oils offer excellent biological properties, but their high lipophilicity limits their bioavailability. This work aimed to develop nanoemulsions based on sunflower and rosehip oils and to evaluate their wound-healing activity. The influence of phospholipids of plant origin on nanoemulsions’ characteristics was investigated. A nanoemulsion prepared with a mixture of phospholipids and synthetic emulsifiers (Nano-1) was compared with another prepared only with phospholipids (Nano-2). The healing activity was evaluated in wounds induced in human organotypic skin explant culture (hOSEC) based on histological and immunohistochemical analysis. The hOSEC wound model was validated, showing that high nanoparticle concentration in the wound bed interferes with cell mobility and the ability to respond to the treatment. Nanoemulsions were 130 to 370 nm, with a concentration of 1013 particles/mL, and a low potential to induce inflammatory processes. Nano-2 was three times larger than Nano-1 but less cytotoxic and could target the oils to the epidermis. Nano-1 permeated intact skin to the dermis and showed a more prominent healing effect than Nano-2 in the hOSEC wound model. Changes in the lipid nanoemulsion stabilizers impacted the cutaneous and cellular penetration of the oils, cytotoxicity, and healing kinetics, resulting in versatile delivery systems.

Iontophoresis in dermal delivery: A review of applications in dermato-cosmetic and aesthetic sciences

OBJECTIVE

Iontophoresis is defined as the use of electric current to drive molecules across cell membranes through an electrolyte solution. In therapeutic context, it is used to facilitate the administration of bioactive substances, either systemically or locally. The technique presents various advantages and that is why it has been successfully used by a plethora of medical sciences. The constantly developing field of dermato-cosmetic science has also taken advantage of the possibilities offered by iontophoresis, aiming to enhance the delivery of the applied active ingredients and, thus, induce the desired cosmetic effects.

METHODS

The available literature was examined for evidence-based reports of safe and successful iontophoresis of pharmaceutical and cosmetic substances, in order to explore different iontophoretic applications in the field of dermato-cosmetic and dermato-aesthetic sciences.

CONCLUSION

Iontophoresis can be safely and successfully used in the treatment of ageing, photoageing, hyperpigmentation, oxidative stress, hair loss, hair removal, acne, acne sequelae and cellulite, providing many possibilities for enhanced treatment results.

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.

A New Approach to Atopic Dermatitis Control with Low-Concentration Propolis-Loaded Cold Cream

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is difficult to treat. Traditional cold cream, a water-in-oil emulsion made from beeswax, is used to alleviate AD symptoms in clinical practice, although its effectiveness has not been scientifically proven. The addition of propolis has the potential to impart anti-inflammatory properties to cold cream. However, in high concentrations, propolis can trigger allergic reactions. Thus, the objective of this work was to develop a cold cream formulation based on purified beeswax containing the same amount of green propolis present in raw beeswax. The impact of adding this low propolis concentration to cold cream on AD control was evaluated in patients compared to cold cream without added propolis (CBlank). Raw beeswax was chemically characterized to define the propolis concentration added to the propolis-loaded cold cream (CPropolis). The creams were characterized as to their physicochemical, mechanical, and rheological characteristics. The effect of CPropolis and CBlank on the quality of life, disease severity, and skin hydration of patients with AD was evaluated in a triple-blind randomized preclinical study. Concentrations of 34 to 120 ng/mL of green propolis extract reduced TNF-α levels in LPS-stimulated macrophage culture. The addition of propolis to cold cream did not change the cream’s rheological, mechanical, or bioadhesive properties. The preclinical study suggested that both creams improved the patient’s quality of life. Furthermore, the use of CPropolis decreased the disease severity compared to CBlank.

Semi-interpenetrating chitosan/ionic liquid polymer networks as electro-responsive biomaterials for potential wound dressings and iontophoretic applications

In this work, electro-responsive chitosan/ionic liquid-based hydrogels were synthetized for the first time, envisaging the development of iontophoretic biomaterials for the controlled release/permeation of charged biomolecules. The main goal was to enhance and tune the physicochemical, mechanical, electro-responsive, and haemostatic properties of chitosan-based biomaterials to obtain multi-stimuli responsive (responsive to electrical current, ionic strength, and pH) and mechanically stable hydrogels. To accomplish this objective, polycationic semi-interpenetrating copolymer networks (semi-IPN) were prepared by combining chitosan (CS) and ionic liquid-based polymers and copolymers, namely poly(1-butyl-3-vinylimidazolium chloride) (poly(BVImCl)) and poly(2-hydroxymethyl methacrylate-co-1-butyl-3-vinylimidazolium chloride) (poly(HEMA-co-BVImCl)). Results show that prepared semi-IPNs presented high mechanical stability and were positively charged over a broad pH range, including basic pH. Semi-IPNs also presented faster permeation and release rates of lidocaine hydrochloride (LH), under external electrical stimulus (0.56 mA/cm²) in aqueous media at 32 °C. The kinetic release constants and the LH diffusion coefficients measured under electrical stimulus were ~1.5 and > 2.7 times higher for those measured for passive release. Finally, both semi-IPNs were non-haemolytic (haemolytic index ≤0.2%) and showed strong haemostatic activity (blood clotting index of ~12 ± 1%). Altogether, these results show that the prepared polycationic semi-IPN hydrogels presented advantageous mechanical, responsive and biological properties that enable them to be potentially employed for the design of new, safer, and advanced stimuli-responsive biomaterials for several biomedical applications such as haemostatic and wound healing dressings and iontophoretic patches.

Towards the advance of a novel iontophoretic patch for needle-free buccal anesthesia

The aim of this work was to develop a mucoadhesive iontophoretic patch for anesthetic delivery in the buccal epithelium. The patch was comprised of three different layers, namely i) drug release (0.64 cm²); ii) mucoadhesive (1.13 cm²); and iii) backing (1.13 cm²). Prilocaine and lidocaine hydrochlorides were used as model drugs (1:1 ratio, 12.5 mg per unit). An anode electrode (0.5 cm² spiral silver wire) was placed in between the drug release and mucoadhesive/backing layers to enable iontophoresis. Surface microscopy; mechanical and in vitro mucoadhesive properties; drug release kinetics and mechanism; and drug permeation through the porcine esophageal epithelium were assessed. Topographic analysis evidenced differences in the physical structures for the several layers. All layers presented suitable handling properties i.e., flexibility, elasticity and resistance. Both the release and mucoadhesive layers presented features of a soft and tough material, while the backing layer matched the characteristics of a hard and brittle material. A synergy between the drug release and mucoadhesive layers on the mucoadhesive force and work of adhesion of the tri-layered patch was observed. Passive drug release of both drugs fitted to First-order, Hixson-Crowell and Weibull kinetic models; and the release mechanism was attributed to anomalous transport. Iontophoresis remarkably enhanced the permeation of both drugs, but mainly prilocaine through the mucosa as evidenced by the permeability coefficient parameter (3.0-fold). The amount of these amino amide salts retained in the mucosa were also equally enhanced (4.7-fold), while the application of a tiny constant electric current (1 mA·cm^-2·h^-1) significantly decreased the lag time for lidocaine permeation by about 45%. In view of possible in vitro / in vivo correlations, the buccal iontophoretic patch displays a promising strategy for needle-free and patient-friendly local anesthesia in dentistry.

Besifloxacin liposomes with positively charged additives for an improved topical ocular delivery

Topical ophthalmic antibiotics show low efficacy due to the well-known physiological defense mechanisms of the eye, which prevents the penetration of exogenous substances. Here, we aimed to incorporate besifloxacin into liposomes containing amines as positively charged additives and to evaluate the influence of this charge on drug delivery in two situations: (i) iontophoretic and (ii) passive treatments. Hypothesis are (i) charge might enhance the electromigration component upon current application improving penetration efficiency for a burst drug delivery, and (ii) positive charge might prolong formulation residence time, hence drug penetration. Liposomes elaborated with phosphatidylcholine (LP PC) or phosphatidylcholine and spermine (LP PC: SPM) were stable under storage at 6 ºC for 30 days, showed mucoadhesive characteristics, and were non-irritant, according to HET-CAM tests. Electron paramagnetic resonance spectroscopy measurements showed that neither the drug nor spermine incorporations produced evident alterations in the fluidity of the liposome's membranes, which retained their structural stability even under iontophoretic conditions. Mean diameter and zeta potential were 177.2 ± 2.7 nm and − 5.7 ± 0.3 mV, respectively, for LP PC; and 175.4 ± 1.9 nm and + 19.5 ± 1.0 mV, respectively, for LP PC:SPM. The minimal inhibitory concentration (MIC) and the minimal bactericide concentration (MBC) of the liposomes for P. aeruginosa showed values lower than the commercial formulation (Besivance). Nevertheless, both formulations presented a similar increase in permeability upon the electric current application. Hence, liposome charge incorporation did not prove to be additionally advantageous for iontophoretic therapy. Passive drug penetration was evaluated through a novel in vitro ocular model that simulates the lacrimal flow and challenges the formulation resistance in the passive delivery situation. As expected, LP PC: SPM showed higher permeation than the control (Besivance). In conclusion, besifloxacin incorporation into positively charged liposomes improved passive topical delivery and can be a good strategy to improve topical ophthalmic treatments.

Silk fibroin for skin injury repair: Where do things stand?

Several synthetic and natural materials are used in soft tissue engineering and regenerative medicine with varying degrees of success. Among them, silkworm silk protein fibroin, a naturally occurring protein-based biomaterial, exhibits many promising characteristics such as biocompatibility, controllable biodegradability, tunable mechanical properties, aqueous preparation, minimal inflammation in host tissue, low cost and ease of use. Silk fibroin is often used alone or in combination with other materials in various formats and is also a promising delivery system for bioactive compounds as part of such repair scenarios. These properties make silk fibroin an excellent biomaterial for skin tissue engineering and repair applications. This review focuses on the promising characteristics and recent advances in the use of silk fibroin for skin wound healing and/or soft-tissue repair applications. The benefits and limitations of silk fibroin as a scaffolding biomaterial in this context are also discussed. STATEMENT OF SIGNIFICANCE: Silk protein fibroin is a natural biomaterial with important biological and mechanical properties for soft tissue engineering applications. Silk fibroin is obtained from silkworms and can be purified using alkali or enzyme based degumming (removal of glue protein sericin) procedures. Fibroin is used alone or in combination with other materials in different scaffold forms, such as nanofibrous mats, hydrogels, sponges or films tailored for specific applications. The investigations carried out using silk fibroin or its blends in skin tissue engineering have increased dramatically in recent years due to the advantages of this unique biomaterial. This review focuses on the promising characteristics of silk fibroin for skin wound healing and/or soft-tissue repair applications.

Iontophoresis enhances voriconazole antifungal potency and corneal penetration

Strategies to enhance corneal penetration of voriconazole (VOR) could improve the treatment of fungal keratitis. Here, we evaluated the use of iontophoresis for ocular VOR delivery from either: (i) a cyclodextrin inclusion complex (CD VOR), (ii) a liposome (LP VOR), and (iii) a chitosan-coated liposome (LP VOR CS). LP VOR CS presented mean diameter of 139.2 ± 1.3 nm and zeta potential equal to + 3.3 ± 1.5 mV compared to 134.6 ± 1.7 and -8.2 ± 3.0 mV of LP VOR, which, together with mucin mucoadhesion study, confirmed chitosan-coating. Both drug and liposomal formulations were stable under the influence of an applied electric current. Interestingly, in vitro studies in Candida glabrata culture indicated a decrease in VOR MIC values following iontophoresis (from 0.28 to 0.14 µg/mL). Iontophoresis enhanced drug penetration into the cornea. After 10 min of a 2 mA/cm² applied current, corneal retained amounts were 45.4 ± 11.2, 30.4 ± 2.1 and 30.6 ± 2.9 µg/cm² for, respectively, CD VOR, LP VOR, and LP VOR CS. In conclusion, iontophoresis increases drug potency and enhances drug penetration into the cornea, showing potential to be used as "an emergency burst delivery approach".

Topical application of silk fibroin-based hydrogel in preventing hypertrophic scars

Current medications for the treatment of hypertrophic scars suffer from bottlenecks of limited therapeutic efficacy and a slow recovery rate. Silk fibroin (SF) has gained attention for its ability to promote wound healing in burns and cutaneous wounds, but its therapeutic effects against hypertrophic scar have not been thoroughly investigated. We prepared SF-based hydrogels (SFHs) with various SF concentrations (1.5 %, 3 %, and 6 %) and characterized their physicochemical properties. Cell experiments showed that these SFHs had favorable biocompatibility in vitro. Further animal experiments in rabbits revealed that the SFH (3 %)-treated group achieved scars on their ears that were thinner and significantly lighter in color compared with the negative control group. Moreover, treatment with SFHs reduced the density and led to the orderly arrangement of collagen fibers. It was found that the therapeutic effects of SFHs were attributed to the reduced expression levels of α-smooth muscle actin. These results are the first to demonstrate that SFH can be exploited as an effective therapeutic agent for the treatment of hypertrophic scars.

Selected Medicines Used in Iontophoresis

Iontophoresis is a non-invasive method of systemic and local drug delivery using an electric field. Iontophoresis enables diffusion of the selected drug via skin, mucosa, enamel, dentin, and other tissues. The amount of delivered therapeutic molecules is about 10⁻2000 times greater than conventional forms of delivery. Among other fields, this method is used in dentistry, ophthalmology, otorhinolaryngology, and dermatology. According to related literature, the most important drugs studied or administered by iontophoresis are: Local anesthetics, opioids, steroids, non-steroidal anti-inflammatory drugs, antibacterial drugs, antifungal drugs, antiviral drugs, anticancer drugs, fluorides, and vitamins. The present review covers current available data regarding the selected medicines used in iontophoresis. Furthermore, indications and conditions of iontophoresis application are reviewed.