Transdermal drug delivery using disk microneedle rollers in a hairless rat model

Applications and prospects of microneedles in tumor drug delivery

As drug delivery devices, microneedles are used widely in the local administration of various drugs. Such drug-loaded microneedles are minimally invasive, almost painless, and have high drug delivery efficiency. In recent decades, with advancements in microneedle technology, an increasing number of adaptive, engineered, and intelligent microneedles have been designed to meet increasing clinical needs. This article summarizes the types, preparation materials, and preparation methods of microneedles, as well as the latest research progress in the application of microneedles in tumor drug delivery. This article also discusses the current challenges and improvement strategies in the use of microneedles for tumor drug delivery.

Recent advances in transdermal drug delivery systems: a review

Various non-invasive administrations have recently emerged as an alternative to conventional needle injections. A transdermal drug delivery system (TDDS) represents the most attractive method among these because of its low rejection rate, excellent ease of administration, and superb convenience and persistence among patients. TDDS could be applicable in not only pharmaceuticals but also in the skin care industry, including cosmetics. Because this method mainly involves local administration, it can prevent local buildup in drug concentration and nonspecific delivery to tissues not targeted by the drug. However, the physicochemical properties of the skin translate to multiple obstacles and restrictions in transdermal delivery, with numerous investigations conducted to overcome these bottlenecks. In this review, we describe the different types of available TDDS methods, along with a critical discussion of the specific advantages and disadvantages, characterization methods, and potential of each method. Progress in research on these alternative methods has established the high efficiency inherent to TDDS, which is expected to find applications in a wide range of fields.

Improvement of a slimming cream's efficacy using a novel fabric as a transdermal drug delivery system: An in vivo and in vitro study

Penetration of any compound into the body from the outside is prevented primarily by the corneal layer of the epidermis. The only way to circumvent the properties of the corneal layer is to disrupt it. Currently, transdermal systems can currently only deliver drugs that are of low molecular weight. The purpose of the present study was to assess the improvement of the slimming cream's efficacy using a novel fabric, with the aim of developing an improved method for transdermal drug delivery. The current study was conducted on four groups of guinea pigs. The control group was untreated, whereas the test groups were treated with either slimming cream and no fabric, slimming cream with 100% cotton fabric or slimming cream with the novel fabric. Ultrasound and microscopic histological analysis were used to assess animals. The results demonstrated that compared with the other groups, the novel fabric group demonstrated the greatest reductions in fat layer thickness, adipocyte size and number and proliferator-activated receptor-γ levels in adipose tissue. Furthermore, the novel fabric also enhanced the transdermal delivery of rhodamine B base and caffeine penetration compared with the control fabric (3.18-fold). In conclusion, the results of the present study demonstrated that the novel fabric can potentially be used to enhance transdermal drug delivery.

An Overview of the Biology of Platelet-Rich Plasma and Microneedling as Potential Treatments for Alopecia Areata

Platelet-rich plasma and microneedling have been investigated recently as potential therapeutic options for the treatment of hair disorders. Evidence from laboratory studies indicates that these treatments enhance growth factor production that in turn facilitates hair follicle development and cycling. Several small studies and case reports have presented encouraging findings regarding the use of these treatments for alopecia areata. Future investigations will be needed to validate these therapeutic techniques for patients with alopecia areata and further refine which subtypes of the disease these methods are best indicated for.

Assessment of solid microneedle rollers to enhance transmembrane delivery of doxycycline and inhibition of MMP activity

Many chronic wounds exhibit high matrix metalloproteinase (MMP) activity that impedes the normal wound healing process. Intradermal delivery (IDD) of sub-antimicrobial concentrations of doxycycline, as an MMP inhibitor, could target early stages of chronic wound development and inhibit further wound progression. To deliver doxycycline intradermally, the skin barrier must be disrupted. Microneedle rollers offer a minimally invasive technique to penetrate the skin by creating multiple microchannels that act as temporary conduits for drugs to diffuse through. In this study, an innovative and facile approach for delivery of doxycycline across Strat-M^TM membrane was investigated using microneedle rollers. The quantity and rate of doxycycline diffusing through the micropores directly correlated with increasing microneedle lengths (250, 500 and 750 μm). Treatment of Strat-M^TM with microneedle rollers resulted in a reduction in fibroblast-mediated collagen gel contraction and MMP activity compared with untreated Strat-M^TM. Our results show that treatment of an epidermal mimetic with microneedle rollers provides sufficient permeabilization for doxycycline diffusion and inhibition of MMP activity. We conclude that microneedle rollers are a promising, clinically ready tool suitable for delivery of doxycycline intradermally to treat chronic wounds.

An Overview of the Biology of Platelet-Rich Plasma and Microneedling as Potential Treatments for Alopecia Areata

Platelet-rich plasma and microneedling have been investigated recently as potential therapeutic options for the treatment of hair disorders. Evidence from laboratory studies indicates that these treatments enhance growth factor production that in turn facilitates hair follicle development and cycling. Several small studies and case reports have presented encouraging findings regarding the use of these treatments for alopecia areata. Future investigations will be needed to validate these therapeutic techniques for patients with alopecia areata and further refine which subtypes of the disease these methods are best indicated for.

Repeated Microneedle Stimulation Induces Enhanced Hair Growth in a Murine Model

Background

Microneedle is a method that creates transdermal microchannels across the stratum corneum barrier layer of skin. No previous study showed a therapeutic effect of microneedle itself on hair growth by wounding.

Objective

The aim of this study is to investigate the effect of repeated microwound formed by microneedle on hair growth and hair growth-related genes in a murine model.

Methods

A disk microneedle roller was applied to each group of mice five times a week for three weeks. First, to identify the optimal length and cycle, microneedles of lengths of 0.15 mm, 0.25 mm, 0.5 mm, and 1 mm and cycles of 3, 6, 10, and 13 cycles were applied. Second, the effect of hair growth and hair-growth-related genes such as Wnt3a, β-catenin, vascular endothelial growth factor (VEGF), and Wnt10b was observed using optimized microneedle. Outcomes were observed using visual inspection, real-time polymerase chain reaction, and immunohistochemistry.

Results

We found that the optimal length and cycle of microneedle treatment on hair growth was 0.25 mm/10 cycles and 0.5 mm/10 cycles. Repeated microneedle stimulation promoted hair growth, and it also induced the enhanced expression of Wnt3a, β-catenin, VEGF, and Wnt10b.

Conclusion

Our study provides evidence that microneedle stimulation can induce hair growth via activation of the Wnt/β-catenin pathway and VEGF. Combined with the drug delivery effect, we believe that microneedle stimulation could lead to new approaches for alopecia.

The effect of nanoemulsion as a carrier of hydrophilic compound for transdermal delivery

The purpose of the present study was to investigate the effect of nanoemulsions as a carrier vehicle of hydrophilic drug for transdermal delivery. The response surface methodology with a mixture design was used to evaluate the effect of ingredient levels of nanoemulsion formulations including cosurfactant (isopropyl alcohol, 20 ∼ 30%), surfactant (mixed of Brij 30 and Brij 35, 20 ∼ 30%), and distilled-water (34.5 ∼ 50.0%) on properties of the drug-loaded nanoemulsions including physicochemical characters and drug permeability through rat skin. The result showed that the hydrophilic drug in aqueous solution with or without penetration enhancer could not transport across rat skin after 12 h of application. Used nanoemulsions as carrier vehicle, the permeation rate of drug was significantly increased from 0 to 63.23 µg/cm2/h and the lag time was shortened from more than 12 h to about 2.7 ∼ 4.0 h. Moreover, the drug-loaded nanoemulsion formulation also showed physicochemical stability after 3 month storage at 25°C and 40°C.

Effect of microemulsions on transdermal delivery of citalopram: optimization studies using mixture design and response surface methodology

The aim of this study was to evaluate the potential of microemulsions as a drug vehicle for transdermal delivery of citalopram. A computerized statistical technique of response surface methodology with mixture design was used to investigate and optimize the influence of the formulation compositions including a mixture of Brij 30/Brij 35 surfactants (at a ratio of 4:1, 20%-30%), isopropyl alcohol (20%-30%), and distilled water (40%-50%) on the properties of the drug-loaded microemulsions, including permeation rate (flux) and lag time. When microemulsions were used as a vehicle, the drug permeation rate increased significantly and the lag time shortened significantly when compared with the aqueous control of 40% isopropyl alcohol solution containing 3% citalopram, demonstrating that microemulsions are a promising vehicle for transdermal application. With regard to the pharmacokinetic parameters of citalopram, the flux required for the transdermal delivery system was about 1280 μg per hour. The microemulsions loaded with citalopram 3% and 10% showed respective flux rates of 179.6 μg/cm(2) and 513.8 μg/cm(2) per hour, indicating that the study formulation could provide effective therapeutic concentrations over a practical application area. The animal study showed that the optimized formulation (F15) containing 3% citalopram with an application area of 3.46 cm(2) is able to reach a minimum effective therapeutic concentration with no erythematous reaction.