Improved Biosafety and Transdermal Delivery of Aconitine via Diethylene Glycol Monoethyl Ether-Mediated Microemulsion Assisted with Microneedles

Novel nano-drug delivery system for natural products and their application

The development of natural products for potential new drugs faces obstacles such as unknown mechanisms, poor solubility, and limited bioavailability, which limit the broadened applicability of natural products. Therefore, there is a need for advanced pharmaceutical formulations of active compounds or natural products. In recent years, novel nano-drug delivery systems (NDDS) for natural products, including nanosuspensions, nanoliposomes, micelle, microemulsions/self-microemulsions, nanocapsules, and solid lipid nanoparticles, have been developed to improve solubility, bioavailability, and tissue distribution as well as for prolonged retention and enhanced permeation. Here, we updated the NDDS delivery systems used for natural products with the potential enhancement in therapeutic efficiency observed with nano-delivery systems.

Preparation and Evaluation of Auxiliary Permeable Microneedle Patch Composed of Polyvinyl Alcohol and Eudragit NM30D Aqueous Dispersion

Poor transdermal permeability limits the possibility of most drug delivery through the skin. Auxiliary permeable microneedles (AP-MNs) with a three-dimensional network structure can effectively break the skin stratum corneum barrier and assist in the transdermal delivery of active ingredients. Herein, we propose a simple method for preparing AP-MNs using polyvinyl alcohol and Eudragit NM30D for the first time. To optimize the formulation of microneedles, the characteristics of swelling properties, skin insertion, solution viscosity, and needle integrity were systematically examined. Additionally, the morphology, mechanical strength, formation mechanism, skin permeability, swelling performance, biocompatibility, and in vitro transdermal drug delivery of AP-MNs were evaluated. The results indicated that the microneedles exhibited excellent mechanical-strength and hydrogel-forming properties after swelling. Further, it proved that a continuous and unblockable network channel was created based on physical entanglement and encapsulation of two materials. The 24 h cumulative permeation of acidic and alkaline model drugs, azelaic acid and matrine, were 51.73 ± 2.61% and 54.02 ± 2.85%, respectively, significantly enhancing the transdermal permeability of the two drugs. In summary, the novel auxiliary permeable microneedles prepared through a simple blending route of two materials was a promising and valuable way to improve drug permeation efficiency.

Recent advancements in the expedition of microneedles: from lab worktops to diagnostic care centers

Microneedle (MN) technology plays a significant role in bioengineering as it allows for minimally invasive exposure to the skin via the non-invasive procedure, increased drug permeability, and improved biological molecule detectability in the epidermal layers, all while improving therapeutic safety and effectiveness. However, MNs have several significant drawbacks, including difficulty scaling up, variability in drug delivery pattern regarding the skin's external environment, blockage of dermal tissues, induction of inflammatory response at the administration site, and limitation of dosing based on the molecular weight of drug and size. Despite these drawbacks, MNs have emerged as a special transdermal theranostics instrument in clinical research to assess physiological parameters. Bioimaging technology relies on microneedles that can measure particular analytes in the extracellular fluid effectively by crossing the stratum corneum, making them "a unique tool in diagnostics detection and therapeutic application inside the body." This review article discusses the recent advances in the applications especially related to the diagnostics and toxicity challenges of microneedles. In addition, this review article discusses the clinical state and commercial accessibility of microneedle technology-based devices in order to provide new information to scientists and researchers.

Assessment of formulation variables of poor water soluble diacerein for its improved loading and anti-inflammatory activity

Dissolving microneedles have become a popular method for percutaneous administrationof drugs. However, loading poorly soluble drugs into water-based dissolving microneedles remains a challenge. In view of this, we aimed to improve Diacerein (DCN) solubility formulating dissolving microneedles. DCN microsuspension was created by high-speed homogenization with organic solvents or wet milling with Tween 80 as a stabilizer (LD1). They were analyzed for particle size and saturation solubility. Subsequently, the organic solvent-based microneedles were prepared under vacuum, whereas LD1 was mixed with HPMC (8% w/w) and PVP (30% w/w) matrix to concentrate the drug in acral fraction through centrifugation. DCN microsuspension in DMSO had the highest drug solubility with an average particle size of 6 µm, whereas LD1 had a particle size of 3.28 µm showing improved solubility. TD-3 had the highest drug loading and the least amount of drug migration into the blank baseplate. Within 5 min, these microneedles dissolved completely in an agarose-gel block. LD1 was likewise put in the baseplate to generate TD3-B. Within 24 h, 74.39% of the medication was released from TD3-B, with only a small amount remaining in the baseplate. TLC examination indicated the conversion of DCN to Rhein in the skin, whereas DSC and TGA studies revealed amorphous features. DCN microneedles showed no sign of skin irritancy but showed anti-inflammatory response on carrageenan-induced paw edema model. Microneedles remained stable during accelerated stability testing. Wet milling in the presence of a stabilizer can be an effective approach for enhancing DCN solubility for improved drug loading in dissolving microneedles. Improvement in solubility of Diacerein for subsequent loading in Dissolving Microneedle for percutaneous delivery.

An insight into current advances on pharmacology, pharmacokinetics, toxicity and detoxification of aconitine

Aconitine is a diterpenoid alkaloid, which mainly exists in the plants of Aconitum. In the last decade, a plethora of studies on the pharmacological activities of aconitine has been conducted and demonstrated that aconitine possessed an extensive range of pharmacological activities such as anti-tumor, anti-inflammatory, analgesic, local anesthesia, and immunomodulatory effects. Pharmacokinetic studies indicated that aconitine may have the characteristics of poor bioavailability, wide distribution, and slow elimination. However, studies have also found that aconitine has toxic effects on the heart, nerves, embryos, etc. Therefore, we believe that aconitine may not be suitable for heart patients and pregnant women to treat related diseases. It is important to note that all of these pharmacological effects require further high-quality studies to determine the clinical efficacy of aconitine. This review aims to summarize the advances in pharmacological, pharmacokinetics, toxicity, and detoxification of aconitine in the last decade with an emphasis on its anti-tumor and anti-inflammatory activities, to provide researchers with the latest information and point out the limitations of relevant research at the current stage and the aspects that should be strengthened in future research.

Recent Advances of Microneedles and Their Application in Disease Treatment

For decades, scientists have been doing a lot of research and exploration to find effective long-term analgesic and/or disease-modifying treatments. Microneedles (MNs) are a simple, effective, and painless transdermal drug delivery technology that has emerged in recent years, and exhibits great promise for realizing intelligent drug delivery. With the development of materials science and fabrication technology, the MN transdermal drug delivery technology has been applied and popularized in more and more fields, including chronic illnesses such as arthritis or diabetes, cancer, dermatocosmetology, family planning, and epidemic disease prevention, and has made fruitful achievements. This paper mainly reviews the latest research status of MNs and their fabrication methodology, and summarizes the application of MNs in the treatment of various diseases, as well as the potential to use nanotechnology to develop more intelligent MNs-based drug delivery systems.

Cholesterol and phospholipid-free multilamellar niosomes regulate transdermal permeation of a hydrophobic agent potentially administrated for treating diseases in deep hair follicles

We designed cholesterol- and phospholipid-free multilamellar niosomes (MLNs) structured by glyceryl monooleate (GMO) and poloxamer 407 (F127), and evaluated their capacity for transdermal drug delivery. The optimized MLNs had a mean size of 97.88 ± 63.25 nm and an encapsulation efficiency of 82.68% ± 2.14%. Notably, the MLNs exhibited a remarkable sustained cargo release. Compared with the tincture, lower transdermal flux but higher skin deposition of aconitine in vitro were achieved in the MLN group (p < 0.05). We further found that MLNs improved the permeability of the stratum corneum. Additionally, both water-soluble rhodamine B- and liposoluble coumarin 6-labeled MLNs were found to penetrate deeply into the skin through the hair follicles and could be internalized by fibroblasts (CCC-ESF-1). The MLNs possessed greater wettability, and the study focused on delivery to deeper hair follicles and up to the outer hair sheath, which showed advantages for treating diseases of hair follicles, and was potentially superior to the hydrophobic PLGA nanoparticles (diameter: 637.87 ± 22.77 nm) which mainly accumulated in superficial hair follicles. Hair follicles were therefore demonstrated to be an important way to enhance skin permeability, and MLNs are a promising alternative for topical and transdermal drug delivery.

Comparative efficacy evaluation of different penetration enhancement strategies for dermal delivery of poorly soluble drugs - A case with sertaconazole nitrate

The aim of this study was to compare the efficacy of different approaches for enhancement of dermal availability of the highly lipophilic antifungal model drug - sertaconazole nitrate (SN). For this purpose, a physical penetration enhancer - dissolving microneedles (MNs) was fabricated by filling moulds with liquid formulation based on polyvinylpyrrolidone and loaded with SN. Dissolving MNs were characterised regarding their morphological and mechanical characteristics. A penetration enhancement efficacy of MNs was evaluated in vitro using porcine ear skin in parallel with the efficacy of formerly developed chemical penetration enhancer - biocompatible microemulsion (ME) formulation. Moreover, an ability of solid silicon MNs to significantly improve delivery of SN from ME into the skin has also been investigated. The obtained results showed that dissolving MNs had satisfying morphological properties and mechanical strength. This type of MNs provided comparable drug deposition in the skin as ME formulation, but also revealed an indication of percutaneous absorption of a portion of the administered drug dose. However, the penetration/permeation study results were largely influenced by experimental setup and dosing regimen. Although solid silicon MNs assisted SN dermal delivery led to increase of drug cutaneous retention (1.9-fold) under infinite dosing regimen, the synergistic action of solid MNs and ME applied under finite dosing was more pronounced in comparison with the application either of physical (dissolving MNs) or chemical enhancer (ME) alone. Namely, SN amount accumulated into the skin increased up to 4.67 and 4.37 folds in comparison with ME and dissolving MNs alone, respectively, while reaching a significant decrease in drug permeation through the skin compared to the use of dissolving MNs. Application of ME per se was the only approach that provided selective in vitro dermal drug delivery without SN permeation across the skin. However, despite both types of the used MNs lead to SN permeation in vitro, the ratio between the drug amount deposited in the skin and SN content permeated was significantly higher for the combined approach (12.05) than for dissolving MNs (2.10). Therefore, a combination of solid silicon MNs and biocompatible ME favoured more pronouncedly SN skin accumulation, which is preferable in the treatment of skin fungal infections.

Emerging era of microneedle array for pharmaceutical and biomedical applications: recent advances and toxicological perspectives

Background

Microneedles (MNs) are the utmost unique, efficient, and minimally invasive inventions in the pharmaceutical field. Over the past decades, many scientists around the globe have reported MNs cautious because of their superb future in distinct areas. Concerning the wise use of MNs herein, we deal in depth with the present applications of MNs in drug delivery.

Main text

The present review comprises various fabrication materials and methods used for MN synthesis. The article also noted the distinctive advantages of these MNs, which holds huge potential for pharmaceutical and biomedical applications. The role of MNs in serving as a platform to treat various ailments has been explained accompanied by unusual approaches. The review also inculcates the pharmacokinetics of MNs, which includes permeation, absorption, and bioavailability enhancement. Besides this, the in vitro/in vivo toxicity, biosafety, and marketed product of MNs have been reviewed. We have also discussed the clinical trials and patents on the pharmaceutical applications of MNs in brief.

Conclusion

To sum up, this article gives insight into the MNs and provides a recent advancement in MNs, which pave the pathway for future pharmaceutical and biomedical applications.

Graphical abstract

Pharmaceutical and biomedical applications of MNs

Comparative HPLC-MS/MS-based pharmacokinetic studies of multiple diterpenoid alkaloids following the administration of Zhenwu Tang and Radix Aconiti Lateralis Praeparata extracts to rats

Abstracts Zhenwu Tang (ZWT) is a traditional Chinese medicine that is primarily composed of Radix Aconiti Lateralis Praeparata (FZ) and diterpenoid alkaloids are believed to be the pharmacologically active compounds of ZWT. In this study, the pharmacokinetic profiles of hypaconitine, mesaconitine, aconitine, benzoylmesaconitine, benzoylaconitine, and benzoylhypacoitine were assessed in rats following intragastric ZWT administration. Furthermore, differences in the pharmacokinetic profiles of these six alkaloids were assessed as a function of rat sex and the administration of ZWT or FZ extracts to these animals. Plasma levels of these alkaloids were quantified via HPLC-MS/MS. Significant differences in key pharmacokinetic parameters were observed when comparing rats administered FZ or ZWT. Relative to FZ extract treatment, ZWT administration was associated with C_max and AUC_0-∞ values of benzoylmesaconitine that were about 3.5 and 5.5 times higher. Considerable variations in hypaconitine pharmacokinetic parameters were also revealed between female and male rats. The C_max and AUC_0-∞ of hypaconitine were about 2.5- and 2.7-fold elevated in female rats in comparison with male rats. These results suggested that the other compounds within ZWT can enhance the absorption of benzoylmesaconitine, while hypaconitine exhibits higher bioavailability in female rats, as compared with male rats.

Advances in Antimicrobial Microneedle Patches for Combating Infections

Skin infections caused by bacteria, viruses and fungi are difficult to treat by conventional topical administration because of poor drug penetration across the stratum corneum. This results in low bioavailability of drugs to the infection site, as well as the lack of prolonged release. Emerging antimicrobial transdermal and ocular microneedle patches have become promising medical devices for the delivery of various antibacterial, antifungal, and antiviral therapeutics. In the present review, skin anatomy and its barriers along with skin infection are discussed. Potential strategies for designing antimicrobial microneedles and their targeted therapy are outlined. Finally, biosensing microneedle patches associated with personalized drug therapy and selective toxicity toward specific microbial species are discussed.

Ionic Liquid-In-Oil Microemulsions Prepared with Biocompatible Choline Carboxylic Acids for Improving the Transdermal Delivery of a Sparingly Soluble Drug

The transdermal delivery of sparingly soluble drugs is challenging due to of the need for a drug carrier. In the past few decades, ionic liquid (IL)-in-oil microemulsions (IL/O MEs) have been developed as potential carriers. By focusing on biocompatibility, we report on an IL/O ME that is designed to enhance the solubility and transdermal delivery of the sparingly soluble drug, acyclovir. The prepared MEs were composed of a hydrophilic IL (choline formate, choline lactate, or choline propionate) as the non-aqueous polar phase and a surface-active IL (choline oleate) as the surfactant in combination with sorbitan laurate in a continuous oil phase. The selected ILs were all biologically active ions. Optimized pseudo ternary phase diagrams indicated the MEs formed thermodynamically stable, spherically shaped, and nano-sized (<100 nm) droplets. An in vitro drug permeation study, using pig skin, showed the significantly enhanced permeation of acyclovir using the ME. A Fourier transform infrared spectroscopy study showed a reduction of the skin barrier function with the ME. Finally, a skin irritation study showed a high cell survival rate (>90%) with the ME compared with Dulbecco's phosphate-buffered saline, indicates the biocompatibility of the ME. Therefore, we conclude that IL/O ME may be a promising nano-carrier for the transdermal delivery of sparingly soluble drugs.