Sonophoresis with ultrasound-responsive liquid-core nuclei for transdermal drug delivery

A, Nayak UY. Low-Frequency Sonophoresis: A Promising Strategy for Enhanced Transdermal Delivery

Sonophoresis is the most approachable mode of transdermal drug delivery system, wherein low-frequency sonophoresis penetrates the drug molecules into the skin. It is an alternative method for an oral system of drug delivery and hypodermal injections. The cavitation effect is thought to be the main mechanism used in sonophoresis. The cavitation process involves forming a gaseous bubble and its rupture, induced in the coupled medium. Other mechanisms used are thermal effects, convectional effects, and mechanical effects. It mainly applies to transporting hydrophilic drugs, macromolecules, gene delivery, and vaccine delivery. It is also used in carrier-mediated delivery in the form of micelles, liposomes, and dendrimers. Some synergistic effects of sonophoresis, along with some permeation enhancers, such as chemical enhancers, iontophoresis, electroporation, and microneedles, increased the effectiveness of drug penetration. Sonophoresis-mediated ocular drug delivery, nail drug delivery, gene delivery to the brain, sports medicine, and sonothrombolysis are also widely used. In conclusion, while sonophoresis offers promising applications in diverse fields, further research is essential to comprehensively elucidate the biophysical mechanisms governing ultrasound-tissue interactions. Addressing these gaps in understanding will enable the refinement and optimization of sonophoresis-based therapeutic strategies for enhanced clinical efficacy.

Smart Physical-Based Transdermal Drug Delivery System:Towards Intelligence and Controlled Release

Transdermal drug delivery systems based on physical principles have provided a stable, efficient, and safe strategy for disease therapy. However, the intelligent device with real-time control and precise drug release is required to enhance treatment efficacy and improve patient compliance. This review summarizes the recent developments, application scenarios, and drug release characteristics of smart transdermal drug delivery systems fabricated with physical principle. Special attention is paid to the progress of intelligent design and concepts in of physical-based transdermal drug delivery technologies for real-time monitoring and precise drug release. In addition, facing with the needs of clinical treatment and personalized medicine, the recent progress and trend of physical enhancement are further highlighted for transdermal drug delivery systems in combination with pharmaceutical dosage forms to achieve better transdermal effects and facilitate the development of smart medical devices. Finally, the next generation and future application scenarios of smart physical-based transdermal drug delivery systems are discussed, a particular focus in vaccine delivery and tumor treatment.

Advancements in Skin-Mediated Drug Delivery: Mechanisms, Techniques, and Applications

Skin-mediated drug delivery methods currently are receiving significant attention as a promising approach for the enhanced delivery of drugs through the skin. Skin-mediated drug delivery offers the potential to overcome the limitations of traditional drug delivery methods, including oral administration and intravenous injection. The challenges associated with drug permeation through layers of skin, which act as a major barrier, are explored, and strategies to overcome these limitations are discussed in detail. This review categorizes skin-mediated drug delivery methods based on the means of increasing drug permeation, and it provides a comprehensive overview of the mechanisms and techniques associated with these methods. In addition, recent advancements in the application of skin-mediated drug delivery are presented. The review also outlines the limitations of ongoing research and suggests future perspectives of studies regarding the skin-mediated delivery of drugs.

Comparative study of permeation effects between vibrating microneedle and low-frequency sonophoresis systems

Microneedle transdermal administration and low-frequency ultrasound represent two important physical penetration-promoting methods for enhancing drug penetration. This article aims to investigate and compare the effects of drug penetration enhancement through transdermal administration using vibrating microneedles versus low-frequency sonophoresis. In Vitro permeation studies were conducted using Valia-Chien double chamber diffusion cells to evaluate the transdermal delivery of tetramethylpyrazine hydrochloride (TMPH). The TMPH concentration in the receiving compartment was determined using high-performance liquid chromatography (HPLC). Several combinations of microneedles and ultrasound settings were investigated, including different needle heights, vibration frequencies, exposure times, and assorted distances of ultrasound horn and skin. The results revealed the vibrating microneedle system as the most efficacious treatment to increase the TMPH permeability into the rat skin. The combination of a larger needle, higher frequency, and a 3-min exposure led to a 41.92-fold increase in cumulative permeability compared to the control group. The ultrasound treatment exhibited a moderate enhancement effect on TMPH skin penetration. Using a horn-to-skin distance of 3 mm and a 3-min exposure resulted in a 4.34-fold increase in TMPH cumulative permeation compared to the control group. It could be concluded that while both the vibrating microneedle and the low-frequency ultrasound systems act as penetration enhancers for promoting the TMPH permeation through the skin, the vibrating microneedle system notably demonstrates a more effective penetration-promoting effect.

Fabrication and Evaluation of Ultrasound-Responsive Emulsion Loading Paclitaxel for Targeted Chemotherapy

Chemotherapy is the most widely used cancer treatment, but it has several drawbacks such as adverse side effects and low bioavailability. To address these limitations, various drug delivery systems have been investigated, including liposomes, micelles, and emulsions. These drug delivery technologies have been improving the efficacy and safety of conventional chemotherapy. This study presents an emerging drug delivery technology for targeted chemotherapy using drug-loaded ultrasound-responsive emulsion (URE) as a drug carrier and ultrasound technology for external activation. URE was designed to be responsive to ultrasound energy and fabricated by using an emulsification technique. To investigate this technology, paclitaxel, as a model drug, was used and encapsulated into URE. The size distribution, morphology, and drug release behavior of paclitaxel-loaded URE (PTX-URE) were characterized, and the echogenicity of PTX-URE was assessed by using ultrasound imaging equipment. The cellular uptake and cytotoxicity of PTX-URE with ultrasound were evaluated in breast cancer cells (MDA-MB-231). Our in vitro results indicate that the combination of PTX-URE and ultrasound significantly enhanced cellular uptake by 10.6-fold and improved cytotoxicity by 24.1% compared to PTX alone. These findings suggest that the URE platform combined with ultrasound is a promising technology to improve the drug delivery efficiency for chemotherapy.

A Conformable Ultrasound Patch for Cavitation-Enhanced Transdermal Cosmeceutical Delivery

Increased consumer interest in healthy-looking skin demands a safe and effective method to increase transdermal absorption of innovative therapeutic cosmeceuticals. However, permeation of small-molecule drugs is limited by the innate barrier function of the stratum corneum. Here, a conformable ultrasound patch (cUSP) that enhances transdermal transport of niacinamide by inducing intermediate-frequency sonophoresis in the fluid coupling medium between the patch and the skin is reported. The cUSP consists of piezoelectric transducers embedded in a soft elastomer to create localized cavitation pockets (0.8 cm² , 1 mm deep) over larger areas of conformal contact (20 cm² ). Multiphysics simulation models, acoustic spectrum analysis, and high-speed videography are used to characterize transducer deflection, acoustic pressure fields, and resulting cavitation bubble dynamics in the coupling medium. The final system demonstrates a 26.2-fold enhancement in niacinamide transport in a porcine model in vitro with a 10 min ultrasound application, demonstrating the suitability of the device for short-exposure, large-area application of sonophoresis for patients and consumers suffering from skin conditions and premature skin aging.

Roller microneedles transdermal delivery of compound lidocaine cream for enhancing the analgesic effect: A randomized self-controlled trial

OBJECTIVE

The purpose of this article is to investigate whether the percutaneous delivery of compound lidocaine cream by roller microneedles can shorten the minimal effective onset time of anesthesia, enhance the intensity of anesthesia and prolong the analgesic time, so as to provide a theoretical basis for exploring a comfortable, safe and effective anesthesia method for photoelectric cosmetic surgery.

METHODS

A total of 90 healthy volunteers, including 18 male and 72 female, met the criteria and were enrolled in the study from December 2020 to September 2021 in Department of Plastic and Burn Surgery of the First Affiliated Hospital of Chongqing Medical University. This study adopted a two-factor randomized block design of 3 (anesthesia time on the test side: 30, 45, 60 min) × 2 (the test side: the left and right side), and the subjects were divided into group A (n = 30), group B (n = 30), and group C (n = 30). On the test side, the compound lidocaine cream was used for topic anesthesia for 10 min, then the roller microneedle was used to roll on the treatment area, compound lidocaine cream was appropriately supplemented, and the topic anesthesia was kept continued for 20 min (group A), 35 min (group B), and 50 min (group C), respectively. The mirrorsymmetrical area of the test side of the three groups was the control side, and the compound lidocaine cream was used for topic anesthesia for 60 min. Photoelectric therapy was performed after anesthesia was completed. The analgesic effect of the subjects on both sides was comprehensively compared; the scores were obtained using the Kuttner Facial Expression Scale, the Frankl Treatment Compliance Scale, the Houpt Behavior Scale, and the Visual Analog Scale (VAS); the satisfaction with anesthesia was investigated. Before and after treatment the skin temperature, color and adverse reactions of the subjects were recorded.

RESULTS

Comparing both sides of the same group, there was no significant difference in terms of the comprehensive evaluation, intraoperative comfort, tolerance, cooperation, pain or satisfaction between the 30-min test side and the routine anesthesia side in group A; the comprehensive evaluation, intraoperative tolerance, cooperation degree, pain degree and satisfaction evaluation of the subjects on the 45-min test side in group B were significantly better than those on the control side; the comprehensive evaluation, intraoperative comfort, tolerance, cooperation, pain and satisfaction of the subjects on the 60-min test side in group C were significantly better than those on the control side. Comparing groups on the control side, there was no significant difference in the comprehensive evaluation, intraoperative comfort, tolerance, cooperation, pain or satisfaction between the three groups of subjects on the control side. Comparing the three groups on the test side, with the prolongation of compound lidocaine cream indwelling time, the subjects' comprehensive evaluation, comfort and pain degree were significantly improved. There was no significant difference in postoperative bruising, swelling, pain, discoloration, redness, or tenderness between the test side and the control side.

CONCLUSION

The percutaneous delivery of compound lidocaine cream by roller microneedles can not only shorten the effective time of anesthesia, but also has a good analgesic effect without obvious adverse reactions.

Mechanisms of ultrasound-microbubble cavitation for inducing the permeability of human skin

We have previously reported that ultrasound (US)-mediated microbubble (MB) cavitation (US-MB) changed the permeability of the skin and significantly enhanced transdermal drug delivery (TDD) without changing the structure of the skin. In this study we found that US-MB enhanced TDD via disruption of epidermal cell-cell junctions and increased matriptase activity. Matriptase is a membrane-bound serine protease regulated by its inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1), and it is expressed in most epithelial tissues under physiologic conditions. Matriptase is expressed in mice after chronic exposure to UV radiation. This study found that US-MB can be used to monitor active matriptase, which rapidly formed the canonical 120-kDa matriptase-HAI-1 complex. These processes were observed in HaCaT human keratinocytes when matriptase activation was induced by US-MB. The results of immunoblot analysis indicated that the matriptase-HAI-1 complex can be detected from 10 min to 3 h after US-MB. Immunohistochemistry (IHC) of human skin revealed that US-MB rapidly increased the activated matriptase, which was observed in the basal layer, with this elevation lasting 3 h. After 3 h, the activated matriptase extended from the basal layer to the granular layer, and then gradually decayed from 6 to 12 h. Moreover, prostasin expression was observed in the epidermal granular layer to the spinous layer, and became more obvious in the granular layer after 3 h. Prostasin was also detected in the cytoplasm or on the cell membrane after 6 h. These results suggest that matriptase plays an important role in recovering from US-MB-induced epidermal cell-cell junction disruption within 6 h. US-MB is therefore a potentially effective method for noninvasive TDD in humans.