Advances in Ultrasound Mediated Transdermal Drug Delivery

Nanozyme-Incorporated Microneedles for the Treatment of Chronic Wounds

Acute wounds are converted to chronic wounds due to advanced age and diabetic complications. Nanozymes catalyze ROS production to kill bacteria without causing drug resistance, while microneedles (MNs) can break through the skin barrier to deliver drugs effectively. Nanozymes can be intergrateded into MNs delivery systems to improve painless drug delivery. It can also reduce the effective dose of drug sterilization while increasing delivery efficiency and effectively killing wounded bacteria while preventing drug resistance. This paper describes various types of metal nanozymes from previous studies and compares their mutual enhancement with nanozymes. The pooled results show that the MNs, through material innovation, are able to both penetrate the scab and deliver nanozymes and exert additional anti-inflammatory and bactericidal effects. The catalytic effect of some of the nanozymes can also accelerate the lysis of the MNs or create a cascade reaction against inflammation and infection. However, the issue of increased toxicity associated with skin penetration and clinical translation remains a challenge. This study reviews the latest published results and corresponding challenges associated with the use of MNs combined with nanozymes for the treatment of wounds, providing further information for future research.

Research progress of physical transdermal enhancement techniques in tumor therapy

The advancement and popularity of transdermal drug delivery (TDD) based on the physical transdermal enhancement technique (PTET) has opened a new paradigm for local tumor treatment. The drug can be directly delivered to the tumor site through the skin, thus avoiding the toxic side effects caused by the first-pass effect and achieving high patient compliance. Further development of PTETs has provided many options for antitumor drugs and laid the foundation for future applications of wearable closed-loop targeting drug delivery systems. In this highlight, the different types of PTETs and related mechanisms, and applications of PTET-related tumor detection and therapy are highlighted. According to their type and characteristics, PTETs are categorized as follows: (1) iontophoresis, (2) electroporation, (3) ultrasound, (4) thermal ablation, and (5) microneedles. PTET-related applications in the local treatment of tumors are categorized as follows: (1) melanoma, (2) breast tumor, (3) squamous cell carcinoma, (4) cervical tumor, and (5) others. The challenges and future prospects of existing PTETs are also discussed. This highlight will provide guidance for the design of PTET-based wearable closed-loop targeting drug delivery systems and personalized therapy for tumors.

Pharmaceutical based cosmetic serums

The growth and demand for cosmeceuticals (cosmetic products that have medicinal or drug-like benefits) have been enhanced for the last few decades. Lately, the newly invented dosage form, i.e., the pharmaceutical-based cosmetic serum has been developed and widely employed in various non-invasive cosmetic procedures. Many pharmaceutical-based cosmetic serums contain natural active components that claim to have a medical or drug-like effect on the skin, hair, and nails, including anti-aging, anti-wrinkle, anti-acne, hydrating, moisturizing, repairing, brightening and lightening skin, anti-hair fall, anti-fungal, and nail growth effect, etc. In comparison with other pharmaceutical-related cosmetic products (creams, gels, foams, and lotions, etc.), pharmaceutical-based cosmetic serums produce more rapid and incredible effects on the skin. This chapter provides detailed knowledge about the different marketed pharmaceutical-based cosmetic serums and their several types such as facial serums, hair serums, nail serums, under the eye serum, lip serum, hand, and foot serum, respectively. Moreover, some valuable procedures have also been discussed which provide prolong effects with desired results in the minimum duration of time after the few sessions of the serum treatment.

Acne and its post-inflammatory hyperpigmentation treatment by applying anti-acne dissolving microneedle patches

OBJECTIVE

Acne is a significant problem in young people. At present, most acne treatment products are topically applied cosmetics, whose efficacy is limited by the stratum corneum. The dissolving microneedle technique can effectively deliver drug molecules into the body. In this study, dissolving microneedles containing anti-acne ingredients were tested for human efficacy and safety.

METHODS

We conducted a 28-day clinical efficacy and safety trial on 30 individuals with visible facial acne. During the trial, anti-acne microneedle (AA-DMN) patches were applied to designated skin areas once daily for 28 consecutive days. Skin pigmentation was measured using a Courage + Khazaka skin melanin and hemoglobin test probe Mexameter MX18. Acne volume was measured using a Canfieldsci skin rapid optical imaging system PRIMOS. In addition, skin irritation was evaluated via self-report and dermatologist's examination.

RESULTS

The AA-DMN patches showed good efficacy including improvement of skin pigmentation and reduced acne volume. Acne volume was reduced by 12.34% after 3 days of patch use and further reduced by 10.01% after 7 continuous days of use. After 28 days of treatment, skin melanin decreased by 5.88% and heme decreased by 7.83%. No adverse reactions were observed in any of the participants.

CONCLUSIONS

Anti-acne microneedle patches showed an excellent effect in reducing acne and post-inflammatory hyperpigmentation (PIH), without adverse skin reactions. The novel AA-DMN patch is a safe and effective anti-acne treatment.

The impact of low intensity ultrasound on cells: Underlying mechanisms and current status

Low intensity ultrasound (LIUS) has been adopted for a variety of therapeutic purposes because of its bioeffects such as thermal, mechanical, and cavitation effects. The mechanism of impact and cellular responses of LIUS in cellular regulations have been revealed, which helps to understand the role of LIUS in tumor treatment, stem cell therapy, and nervous system regulation. The review summarizes the bioeffects of LIUS at the cellular level and its related mechanisms, detailing the corresponding theoretical basis and latest research in the study of LIUS in the regulation of cells. In the future, the design of specific LIUS-mediated treatment strategies may benefit from promising investigations which is hoped to provide encouraging therapeutic data.

Multifunctional Inverse Opal Microneedle Arrays for Drug Delivery and Monitoring

Microneedle arrays (MNs) have a demonstrated value in transdermal drug delivery systems. Attempts to this technology focus on the generation of functional MNs to achieve intelligent drug delivery. Here, multifunctional inverse opal microneedle (IOMN) arrays with the abilities are reported to load various drugs and monitor drug release. The IOMNs are generated by using poly(ethylene glycol) diacrylate (PEGDA) to replicate hierarchical structure templates that are composed of self-assembled silica colloidal nanoparticles in the inverted cone structure wells. Because of their interconnected porous structures, different actives, or drugs can be loaded into the IOMNs without organic solvents and chemical polymerization. It is demonstrated that when these drugs loaded IOMNs pierce the skin at position of interest and for slow release, the average refractive index of the IOMNs decreases with the release process, resulting in a corresponding blueshift of their characteristic spectrum. Thus, by measuring the wavelength shift value of the IOMNs, the amount of released drugs can be monitored, providing essential guidance for efficient clinical treatment. These features indicate that the IOMNs are valuable smart drug delivery systems in personalized therapy.

Transdermal Delivery of Therapeutic Compounds With Nanotechnological Approaches in Psoriasis

Psoriasis is a chronic, immune-mediated skin disorder involving hyperproliferation of the keratinocytes in the epidermis. As complex as its pathophysiology, the optimal treatment for psoriasis remains unsatisfactorily addressed. Though systemic administration of biological agents has made an impressive stride in moderate-to-severe psoriasis, a considerable portion of psoriatic conditions were left unresolved, mainly due to adverse effects from systemic drug administration or insufficient drug delivery across a highly packed stratum corneum via topical therapies. Along with the advances in nanotechnologies, the incorporation of nanomaterials as topical drug carriers opens an obvious prospect for the development of antipsoriatic topicals. Hence, this review aims to distinguish the benefits and weaknesses of individual nanostructures when applied as topical antipsoriatics in preclinical psoriatic models. In view of specific features of each nanostructure, we propose that a proper combination of distinctive nanomaterials according to the physicochemical properties of loaded drugs and clinical features of psoriatic patients is becoming a promising option that potentially drives the translation of nanomaterials from bench to bedside with improved transdermal drug delivery and consequently therapeutic effects.

Transdermal delivery for gene therapy

Gene therapy is a critical constituent of treatment approaches for genetic diseases and has gained tremendous attention. Treating and preventing diseases at the genetic level using genetic materials such as DNA or RNAs could be a new avenue in medicine. However, delivering genes is always a challenge as these molecules are sensitive to various enzymes inside the body, often produce systemic toxicity, and suffer from off-targeting problems. In this regard, transdermal delivery has emerged as an appealing approach to enable a high efficiency and low toxicity of genetic medicines. This review systematically summarizes outstanding transdermal gene delivery methods for applications in skin cancer treatment, vaccination, wound healing, and other therapies.

Microneedle-Mediated Vaccination: Innovation and Translation

Vaccine administration by subcutaneous or intramuscular injection is the most commonly prescribed route for inoculation, however, it is often associated with some deficiencies such as low compliance, high professionalism, and risk of infection. Therefore, the application of microneedles for vaccine delivery has gained widespread interests in the past few years due to its high compliance, minimal invasiveness, and convenience. This review focuses on recent advances in the development and application of microneedles for vaccination based on different delivery strategies, and introduces the current status of microneedle-mediated vaccination in clinical translation. The prospects for its application including opportunities and challenges are further discussed.

Topical delivery of gambogic acid assisted by the combination of low-frequency ultrasound and chemical enhancers for chemotherapy of cutaneous melanoma

Anti-cutaneous melanoma activity of the skin-delivered gambogic acid (GA) has been reported in our previous study. However, it is difficult for GA to diffuse passively through intact skin without any enhancement means. In this study, a combination of chemical enhancers (EN: azone and propylene glycol) and physical ultrasound (US) was used to improve the percutaneous permeation of GA and enhance the anti-melanoma activity. The enhancement effect of the combination of EN and US (EN-US) on GA in vitro and in vivo was studied, and the enhancement mechanism and skin irritation were also evaluated. We showed that the parameters of US application at a constant frequency (30 kHz) with a duty cycle of 100% and intensity of 1.75 W/cm² for 20 min were optimal. In vitro, EN-US showed a considerable enhancement of the permeation of GA, and the enhancement effect was stronger than that with the use of EN or US alone. In vivo antitumor study showed that the tumor growth was significantly inhibited after percutaneous administration of GA by EN-US, more than in the intravenous injection group. The penetration enhancement mechanism revealed that EN-US not only altered the structure of lipid bilayers and keratins to reduce the barrier effect of the stratum corneum but also produced diffusion channels in the skin under the cavitation effect of US, thereby promoting the skin penetration of GA. In addition, there was no observable skin irritation in mice after treatment with EN-US. Our study demonstrated that the combination of EN and US improved the skin permeation and retention of GA to enhance the anti-melanoma activity. This method also provides technical guidance for the future development of topical and transdermal therapeutic system of GA.

Transdermal Delivery of Chemotherapeutics: Strategies, Requirements, and Opportunities

Chemotherapeutic drugs are primarily administered to cancer patients via oral or parenteral routes. The use of transdermal drug delivery could potentially be a better alternative to decrease the dose frequency and severity of adverse or toxic effects associated with oral or parenteral administration of chemotherapeutic drugs. The transdermal delivery of drugs has shown to be advantageous for the treatment of highly localized tumors in certain types of breast and skin cancers. In addition, the transdermal route can be used to deliver low-dose chemotherapeutics in a sustained manner. The transdermal route can also be utilized for vaccine design in cancer management, for example, vaccines against cervical cancer. However, the design of transdermal formulations may be challenging in terms of the conjugation chemistry of the molecules and the sustained and reproducible delivery of therapeutically efficacious doses. In this review, we discuss the nano-carrier systems, such as nanoparticles, liposomes, etc., used in recent literature to deliver chemotherapeutic agents. The advantages of transdermal route over oral and parenteral routes for popular chemotherapeutic drugs are summarized. Furthermore, we also discuss a possible in silico approach, Formulating for Efficacy™, to design transdermal formulations that would probably be economical, robust, and more efficacious.

Role of the active cycle of breathing technique combined with phonophoresis for the treatment of patients with chronic obstructive pulmonary disease (COPD): study protocol for a preliminary randomized controlled trial

Background

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease characterized by coughing, the production of excess sputum, and dyspnea. Patients with excessively thick sputum may have frequent attacks or develop more serious disease. The guidelines recommend airway clearance for patients with excessive sputum who are hospitalized with COPD. The active cycle of breathing technique is the most common non-pharmacological airway clearance technique used by physiotherapists. However, the effectiveness of the technique is not always guaranteed. Active cycle of breathing techniques require the initial dilution of the sputum, usually by inhalation drugs, which may have limited effects. Recent studies have found that phonophoresis decreases inflammation, suggesting the potential of the combined usage of active cycle of breathing techniques and phonophoresis. Therefore, the aim of this study is to explore the effectiveness and safety of combining active cycle of breathing technique and phonophoresis in treating COPD patients.

Methods and analysis

We propose a single-blind randomized controlled trial using 75 hospitalized patients diagnosed with COPD with excessive sputum production. The patients will be divided into three groups. The intervention group will receive active cycle of breathing techniques combined with phonophoresis. The two comparison groups will be treated with active cycle of breathing techniques and phonophoresis, respectively. The program will be implemented daily for 1 week. The primary outcomes will be changes in sputum viscosity and production, lung function, and pulse oximetry. Secondary outcomes include the assessment of COPD and anxiety, measured by the COPD Assessment Test scale and the Anxiety Inventory for Respiratory Disease, respectively; self-satisfaction; the degree of cooperation; and the length of hospital stay. All outcome measures, with the exception of sputum production and additional secondary outcomes, will be assessed at the commencement of the study and after 1 week’s intervention. Analysis of variance will be used to investigate differences between the groups, and a p-value of less than 0.05 (two-tailed) will be considered statistically significant.

Discussion

This study introduces a combination of active cycle of breathing techniques and phonophoresis to explore the impact of these interventions on patients hospitalized with COPD. If this combined intervention is shown to be effective, it may prove to be a better treatment for patients with COPD.

Trial registration

The trial was registered prospectively on the Chinese Clinical Trial Registry on 24 December 2019.ClinicalTrials.gov ChiCTR1900028506. Registered on December 2019.

Plumbagin-Loaded Glycerosome Gel as Topical Delivery System for Skin Cancer Therapy

Plumbagin (PLM) is a phytochemical which has shown cytotoxicity against of cancer cells both in vitro and in vivo. However, the clinical application of PLM has been hindered due to poor aqueous solubility and low bioavailability. The aim of the present study was to develop, optimize and evaluate PLM-loaded glycerosome (GM) gel and compare with conventional liposome (CL) for therapeutic efficacy against skin cancer. The GM formulations were optimized by employing design expert software by 3-level 3-factor design. The prepared GMs were characterized in vitro for vesicle size, size distribution, zeta potential, vesicle deformability, drug release, skin permeation, retention, texture, antioxidant and cytotoxicity activities. The optimized formulation showed a vesicle size of 119.20 ± 15.67 nm with a polydispersity index (PDI) of 0.145 ± 0.02, the zeta potential of −27 ± 5.12 mV and entrapment efficiency of 76.42 ± 9.98%. The optimized PLM-loaded GM formulation was transformed into a pre-formed gel which was prepared using Carbopol 934 polymer. The drug diffusion fluxes of CL gel and GM-loaded gel were 23.31 ± 6.0 and 79.43 ± 12.43 µg/cm²/h, respectively. The result of texture analysis revealed the adequate hardness, cohesiveness, consistency, and viscosity of the developed GM-loaded gel compared to CL gel. The confocal images showed that glycerosomal gel has deeper skin layer penetration as compared to the control solution. GM-loaded gel treated rat skin showed significantly (p < 0.05) higher drug accumulation in the dermis, higher cytotoxicity and higher antioxidant activity as compared to CL gel and PLM suspension. Thus, findings revealed that novel GM-loaded gel could be potential carriers for therapeutic intervention in skin cancer.

Atmospheric Pressure Plasma Irradiation Facilitates Transdermal Permeability of Aniline Blue on Porcine Skin and the Cellular Permeability of Keratinocytes with the Production of Nitric Oxide

The transdermal delivery system of nutrients, cosmetics, and drugs is particularly attractive for painless, noninvasive delivery and sustainable release. Recently, atmospheric pressure plasma techniques have been of great interest to improve the drug absorption rate in transdermal delivery. Currently, plasma-mediated changes in the lipid composition of the stratum corneum are considered a possible mechanism to increase transdermal permeability. Nevertheless, its molecular and cellular mechanisms in transdermal delivery have been largely confined and still veiled. Herein, we present the effects of cold plasma on transdermal transmission on porcine skin and the cellular permeability of keratinocytes and further demonstrate the production of nitric oxide from keratinocytes. Consequently, argon plasma irradiation for 60 s resulted in 2.5-fold higher transdermal absorption of aniline blue dye on porcine skin compared to the nontreated control. In addition, the plasma-treated keratinocytes showed an increased transmission of high-molecular-weight molecules (70 and 150 kDa) with the production of nitric oxide. Therefore, these findings suggest a promoting effect of low-temperature plasma on transdermal absorption, even for high-molecular-weight molecules. Moreover, plasma-induced nitric oxide from keratinocytes is likely to regulate transdermal permeability in the epidermal layer.

Clinical Efficacy of Ultrasound-Mediated Transdermal Lidocaine and Capsaicin Delivery for the Treatment of Allodynia Caused by Herpes Zoster

OBJECTIVE

To investigate the efficacy of ultrasound-mediated drug delivery for allodynia caused by herpes zoster.

DESIGN

Unblinded randomized controlled study with two treatment groups and an additional control group.

SUBJECTS

Patients hospitalized with allodynia caused by herpes zoster were enrolled.

METHODS

Patients were randomly assigned to three groups: ultrasound-mediated transdermal drug delivery (group U), lidocaine intradermal injection (group I), or control group (group C). The primary outcome was pain intensity associated with allodynia, assessed with the visual analog scale (VAS) while brushing the skin with clothing after treatment stimulated allodynia. The secondary outcomes included an emotional functioning score (ES), average gabapentin consumption, and incidence of adverse events of each group.

RESULTS

Sixty patients were enrolled in the study, but two of them failed to complete the treatment process. Therefore, 58 patients were included in the final analysis. All groups had lower VAS and ES scores after treatment compared with baseline. The VAS scores in groups U and I decreased significantly more than in group C (P < 0.05). Mean VAS scores in group U on days 1, 2, and 3 were lower than in group C (P < 0.01). ES was significantly lower in group U compared with groups I and C after treatment (P < 0.001). Average gabapentin consumption and incidence of adverse events in group C were higher than in the other two groups.

CONCLUSIONS

In this study of treatment of allodynia caused by herpetic zoster, ultrasound-mediated lidocaine and capsaicin delivery provided better pain relief and improved emotional functioning compared with intradermal blockade with local anesthetics.

Ultrasound-mediated topical delivery of econazole nitrate with potential for treating Raynaud's phenomenon

The study aims to assess the ultrasound-assisted econazole nitrate (EN) permeation from topically applied formulations with potential for treating Raynaud's phenomenon. Optimization of ultrasound parameters such as the distance of the horn, application time and amplitude were performed. In vitro percutaneous absorption studies were performed using econazole formulations (F2_HPMC dispersion, F4_Lipoderm® Activemax™ Cream) across the ultrasound-treated porcine skin and were compared with the control group (skin samples without ultrasound). Histology and ATR-FTIR studies were performed on treated skin samples. A constant frequency (20 kHz) ultrasound application with 40% amplitude, 0.5 cm distance between ultrasound horn and the skin surface for 2 min was optimized. The permeation of EN was found to be higher from ultrasound-treated skin samples than the control group. Drug permeation from F2_HPMC dispersion was found to be higher as compared to the other formulations and the marketed EN cream. Histological evaluation confirmed that F2_HPMC dispersion showed no signs of toxicity. ATR-FTIR studies revealed a slight increase in the CH₂ stretching vibrations (~2920 cm^-1 and 2850 cm^-1) in ultrasound-treated skin samples as compared with the control. In conclusion, the ultrasound-assisted transdermal delivery of F2_HPMC dispersion could be further studied as a new therapy for Raynaud's phenomenon.

Effect of Ultrasound Intensity and Mode on Piroxicam Transport Across Three-Dimensional Skin Equivalent Epiderm™

BACKGROUND

Transdermal drug delivery has many advantages compared to other routes. However, the barrier function of the stratum corneum limits the use of the skin as an administrative route for medications. Different methods were investigated to alter the barrier function of the stratum corneum and it was found that applying different ultrasound waves could enhance the skin's permeability.

OBJECTIVE

The aim of this work is to study the effect of ultrasonic waves on the alteration of skin natural barrier function, to improve the permeability of the skin to Piroxicam using three-dimension skin (EpiDermTM) as a skin model for the investigation.

METHOD

The effect of ultrasound at 1 MHz and 20 kHz on the permeation of Piroxicam across the three-dimensional skin equivalent using a Franz diffusion cell, was evaluated and the concentration of Piroxicam in the receiving compartment was determined using liquid chromatography method.

RESULTS

The permeation of Piroxicam enhanced by 199% when therapeutic ultrasound at 1 MHz frequency was used. Significant permeation enhancement was also found upon utilizing low frequency sonophoresis at 20 kHz (427%) with no apparent damage to the membrane.

CONCLUSION

Sonophoresis has a positive effect on enhancing skin permeability. The enhancement level was largely dependent on the sonication factors; frequency, intensity and length of treatment. Multiple mechanisms of action might be involved in permeation improvement of the piroxicam molecule. Those mechanisms are largely dependent on the ultrasonic conditions.