Tolerability of a piezoelectric microneedle electroporator in human subjects.

Electroporation, or the use of electric pulses to facilitate the intracellular delivery of DNA, RNA, and other molecules, is a well-established technique, that has been demonstrated to significantly augment the immunogenicity of DNA/mRNA vaccines and therapeutics. However, the clinical translation of traditional electroporators has been limited due to high costs, large size, complex user operation, and poor tolerability in humans due to nerve stimulation. In prior work, we introduced ePatch: an ultra-low-cost, handheld, battery-free electroporator employing a piezoelectric pulser coupled with a microneedle electrode array that showed enhanced immunogenic responses to an intradermal SARS-CoV-2 DNA vaccine in mice. The current study shifts focus from efficacy to tolerability, hypothesizing that ePatch's microneedle array, which localizes the electric field to the superficial skin strata, will minimize nerve stimulation and improve patient comfort. We tested this hypothesis in 14 healthy adults, monitoring pain and other potential adverse effects associated with electroporation. Compared to the insertion of a traditional hypodermic needle, the ePatch was less painful. Adverse effects such as pain, tenderness, erythema and swelling at the application sites were minimal, transient, and statistically indistinguishable between the experimental and placebo ePatch application, suggesting excellent tolerability towards electroporation. In summary, ePatch has a favorable tolerability profile in humans and offers the potential for the safe use of electroporation in a variety of clinical settings, including DNA and mRNA vaccination.

A statistical approach on distribution and seasonal habitat use of waterfowl and shorebirds in Çildir Lake (Ardahan, Türkiye).

Wetlands are crucial habitats for both migrant and resident bird assemblages. The distribution and habitat preferences of birds in aquatic ecosystems are significantly influenced by environmental and ecological factors that critically impact the relevant habitats. In order to reveal the distribution and habitat preferences of the birds, many statistical models and methodologies are employed in ecology and conservation biology. Herein, we investigated the effects of year, season, habitat, and species variables on the distribution and population dynamics of waterfowls and shorebirds associated with the wetland. In this regard, field surveys were carried out in and around Çildir Lake (Ardahan, Türkiye) between April 2017 and September 2018 to examine the distribution of waterfowls and shorebirds and variations in population sizes. As an experimental design, a stratified random sampling design was used to assess bird fauna in the four dominant habitat types (open water surface, reeds, grasslands, and agricultural areas) in the study area. Accordingly, a total of 51 waterfowl and shorebird species were identified during the study period. Of the identified families, Anatidae (n = 18), Scolopacidae (n = 8), and Ardeidae (n = 8) were the most common families. Considering bird species, common coot Fulica atra and mallard Anas platyrhynchos were the most abundant species. The dependent variable (bird populations) was compared with the independent variables (year, season, habitat, and species). The population in 2018 decreased by 13% in comparison to the population in 2017 (p < 0.05). Once the reed area was considered as the reference, the population density in the water surface habitat increased by 65% (p < 0.001). In relation to seasonal reference, a 65% increase in population growth in spring was recorded in comparison to the growth in fall (p < 0.001). On the other hand, no statistical differences were noted in population growth in winter and summer ((p > 0.05). With respect to the reference species (Anas crecca), critical differences in species fluctuation were observed among species (p < 0.001). Consequently, the findings of the present study suggest that seasonal factor might be of the substantial factors linked to the habitat composition. However, more descriptive and predictive analytical methods are needed beyond classical regression approaches in habitat use and selection studies at bird ecology.

Fabrication of pure-drug microneedles for delivery of montelukast sodium.

Dissolving microneedle (MN) patches are usually formulated with a blend of drug and excipients added for mechanical strength and drug stabilization. In this study, we developed MNs made of pure drug to maximize drug loading capacity. MN patches were fabricated for transdermal delivery of montelukast sodium (MS) which is used to treat asthma and allergic rhinitis. We developed three different fabrication methods - solvent casting, melt casting, and solvent washing - and determined that filling molds with MS powder followed by a solvent washing method enabled MS to be loaded selectively to the MNs. Drug localization was confirmed with Raman imaging. MNs were able to penetrate in vitro and ex vivo skin models, and maintained strong mechanical properties during 6 months' storage at 22 °C. MS was also stable and compatible with the formulation used for the patch backing layer after 3 months' storage at 40 °C. MS delivery efficiency into skin was 55%, which enabled delivery of 3.2 mg MS into porcine skin ex vivo, which is in the range of MS doses in human clinical use. We conclude that the solvent washing method can be used to prepare MNs containing pure drug, such as MS at milligram doses in a ~ 1 cm2 MN patch.

Trends of microneedle technology in the scientific literature, patents, clinical trials and internet activity.

The powerful and intriguing idea that drives the emerging technology of microneedles-shrinking the standard needle to a micron scale-has fostered an entire field of microneedle study and subsequent exponential growth in research and product development. Originally enabled by microfabrication tools derived from the microelectronic industry, microneedles are now produced through a number of methods in a variety of forms including solid, coated, dissolvable, and hollow microneedles. They are used to deliver a broad spectrum of molecules, including small molecules, biomolecules, and vaccines, as well as various forms of energy into the skin, eye, and other tissues. Microneedles are also being exploited for use in diagnostics, as well as additional medical, cosmetic, and other applications. This review elucidates the relative roles of different aspects of microneedle technology development, as shown through scientific papers, patents, clinical studies, and internet/social media activity. Considering >1000 papers, 750 patents, and almost 80 clinical trials, we analyze different attributes of microneedles such as usage of microneedles, types of microneedles, testing environment, types of patent claims, and phases of clinical trials, as well as which institutions and people in academia and industry from different locations and in different journals are publishing, patenting, and otherwise studying the potential of microneedles. We conclude that there is robust and growing activity in the field of microneedles; the technology is rapidly developing and being used for novel applications to benefit human health and well-being.

Fabrication of Montelukast sodium loaded filaments and 3D printing transdermal patches onto packaging material.

The main objectives of this work were to develop and characterize new 3D printing filaments and print them directly onto a packaging material. Different blends of polymers were tested to achieve low-temperature printing filaments, which are flexible and durable to be wound onto spools. The mechanical properties of filaments were compared with commercial filaments and evaluated by bending tests. Kollidon 12PF, PEG 4000, and PEO 900k blends resulted in promising filaments that could be extruded at 70 °C and had flexibility similar to commercial PLA filaments. Montelukast sodium (MS), which undergoes hepatic first-pass metabolism, was compounded into polymer blends, and drug-loaded filaments were extruded. All filaments were tested with a 3D printing pen prior to using with the 3D printer for transdermal patches. MS loaded filaments and patches showed similar flexibility with placebo. In vitro drug release studies showed 52% of MS was released in 24 h. Printing on disposable packaging material is presented for the first time with this study. Build plate adhesion and cohesion of 3D printed layers were successfully achieved. This new technique could prevent cross-contamination, save time, and provide ease of use, which can take us one step closer to the production of personalized drugs in pharmacies.

Effective topical delivery systems for corticosteroids: dermatological and histological evaluations.

Atopic dermatitis (AD) is a chronic and relapsing skin disease with severe eczematous lesions. Long-term topical corticosteroid treatment can induce skin atrophy, hypopigmentation and transepidermal water loss (TEWL) increase. A new treatment approach was needed to reduce the risk by dermal targeting. For this purpose, Betamethasone valerate (BMV)/Diflucortolone valerate (DFV)-loaded liposomes (220-350 nm) were prepared and incorporated into chitosan gel to obtain adequate viscosity (∼13 000 cps). Drugs were localized in stratum corneum + epidermis of rat skin in ex-vivo permeation studies. The toxicity was assessed on human fibroblast cells. In point of in-vivo studies, pharmacodynamic responses, treatment efficacy and skin irritation were evaluated and compared with previously prepared nanoparticles. Liposome/nanoparticle in gel formulations produced higher paw edema inhibition in rats with respect to the commercial cream. Similar skin blanching effect with commercial creams was obtained via liposome in gels although they contain 10 times less drug. Dermatological scoring results, prognostic histological parameters and suppression of mast cell numbers showed higher treatment efficiency of liposome/nanoparticle in gel formulations in AD-induced rats. TEWL and erythema measurements confirmed these results. Overview of obtained results showed that liposomes might be an effective and safe carrier for corticosteroids in skin disease treatment.

Enhanced dermal delivery of diflucortolone valerate using lecithin/chitosan nanoparticles: in-vitro and in-vivo evaluations.

The objective of this study was to prepare a suitable formulation for dermal delivery of diflucortolone valerate (DFV) that would maintain the localization in skin layers without any penetration and to optimize efficiency of DFV. Drug-loaded lecithin/chitosan nanoparticles with high entrapment efficiency (86.8%), were successfully prepared by ionic interaction technique. Sustained release of DFV was achieved without any initial burst release. Nanoparticles were also incorporated into chitosan gel at different ratios for preparing a more suitable formulation for topical drug delivery with adequate viscosity. In ex-vivo permeation studies, nanoparticles increased the accumulation of DFV especially in the stratum corneum + epidermis of rat skin without any significant permeation. Retention of DFV from nanoparticle in chitosan gel formulation (0.01%) was twofold higher than commercial cream, although it contained ten times less DFV. Nanoparticles in gel formulations produced significantly higher edema inhibition in rats compared with commercial cream in in-vivo studies. Skin blanching assay using a chromameter showed vasoconstriction similar to that of the commercial product. There were no barrier function changes upon application of nanoparticles. In-vitro and in-vivo results demonstrated that lecithin/chitosan nanoparticles in chitosan gel may be a promising carrier for dermal delivery of DFV in various skin disorders.

Comparison of PLGA and lecithin/chitosan nanoparticles for dermal targeting of betamethasone valerate.

Poly(lactide-co-glycolide) (PLGA) and lecithin/chitosan (LC) nanoparticles were prepared to evaluate the difference in the behavior upon administration on skin, for steroidal treatment. For this purpose, betamethasone-17-valerate (BMV)-loaded nanoparticles with a narrow size distribution and high entrapment efficiency were prepared. Permeation studies showed that both polymeric nanoparticles enhanced the amount of BMV in epidermis, which is the target site of topical steroidal treatment, when compared with commercial formulation. 1.58-Fold increase was determined in the epidermis concentration of BMV by LC nanoparticles with respect to PLGA nanoparticles. Nanoparticles were diluted in chitosan gel (10%, w/w) to prepare suitable formulation for topical application. Accumulation from both gel formulations were found significantly higher than commercial formulation in skin layers (p < 0.05). In addition, pharmacodynamic responses were also investigated as anti-inflammatory and skin-blanching parameters. Both formulations significantly improved these parameters although they contained 10 times less amount of BMV than commercial cream. Moreover, TEWL measurement exhibited no barrier function changes upon the application of nanoparticles on skin. Overall, both nanoparticles improved the localization of BMV within skin layers; but when compared with PLGA nanoparticles, the LC nanoparticles could be classified as a better candidate for topical delivery vehicle in the treatment of various dermatological inflammatory diseases.