Microneedle-Mediated Transdermal Delivery of Genetic Materials, Stem Cells, and Secretome: An Update and Progression.

Medical practitioners commonly use oral and parenteral dosage forms to administer drugs to patients. However, these forms have certain drawbacks, particularly concerning patients' comfort and compliance. Transdermal drug delivery presents a promising solution to address these issues. Nevertheless, the stratum corneum, as the outermost skin layer, can impede drug permeation, especially for macromolecules, genetic materials, stem cells, and secretome. Microneedles, a dosage form for transdermal delivery, offer an alternative approach, particularly for biopharmaceutical products. In this review, the authors will examine the latest research on microneedle formulations designed to deliver genetic materials, stem cells, and their derivatives. Numerous studies have explored different types of microneedles and evaluated their ability to deliver these products using preclinical models. Some of these investigations have compared microneedles with conventional dosage forms, demonstrating their significant potential for advancing the development of biotherapeutics in the future.

Fabrication of dissolving microneedles for transdermal delivery of protein and peptide drugs: polymer materials and solvent casting micromoulding method.

Proteins and peptides are rapidly developing pharmaceutical products and are expected to continue growing in the future. However, due to their nature, their delivery is often limited to injection, with drawbacks such as pain and needle waste. To overcome these limitations, microneedles technology is developed to deliver protein and peptide drugs through the skin. One type of microneedles, known as dissolving microneedles, has been extensively studied for delivering various proteins and peptides, including ovalbumin, insulin, bovine serum albumin, polymyxin B, vancomycin, and bevacizumab. This article discusses polymer materials used for fabricating dissolving microneedles, which are poly(vinylpyrrolidone), hyaluronic acid, poly(vinyl alcohol), carboxymethylcellulose, GantrezTM, as well as other biopolymers like pullulan and ulvan. The paper is focused solely on solvent casting micromoulding method for fabricating dissolving microneedles containing proteins and peptides, which will be divided into one-step and two-step casting micromoulding. Additionally, future considerations in the market plan for dissolving microneedles are discussed in this article.

Combination of Dissolving Microneedles with Nanosuspension and Co-Grinding for Transdermal Delivery of Ketoprofen.

Ketoprofen is an anti-inflammatory agent that may cause gastric irritation if administered orally. Dissolving microneedles (DMN) can be a promising strategy to overcome this issue. However, ketoprofen has a low solubility; therefore, it is essential to enhance its solubility using certain methods, namely nanosuspension (NS) and co-grinding (CG). This research aimed to formulate DMN containing ketoprofen-loaded NS and CG. Ketoprofen NS was formulated with poly(vinyl alcohol) (PVA) at concentrations of 0.5%, 1%, and 2%. CG was prepared by grinding ketoprofen with PVA or poly(vinyl pyrrolidone) (PVP) at different drug-polymer ratios. The manufactured ketoprofen-loaded NS and CG were evaluated in terms of their dissolution profile. The most promising formulation from each system was then formulated into microneedles (MNs). The fabricated MNs were assessed in terms of their physical and chemical properties. An in vitro permeation study using Franz diffusion cells was also carried out. The most promising MN-NS and MN-CG formulations were F4-MN-NS (PVA 5%-PVP 10%), F5-MN-NS (PVA 5%-PVP 15%), F8-MN-CG (PVA 5%-PVP 15%), and F11-MN-CG (PVA 7.5%-PVP 15%), respectively. The cumulative amounts of drug permeated after 24 h for F5-MN-NS and F11-MN-CG were 3.88 ± 0.46 µg and 8.73 ± 1.40 µg, respectively. In conclusion, the combination of DMN with nanosuspension or a co-grinding system may be a promising strategy for delivering ketoprofen transdermally.

Enhancing Intradermal Delivery of Lidocaine by Dissolving Microneedles: Comparison between Hyaluronic Acid and Poly(Vinyl Pyrrolidone) Backbone Polymers.

Lidocaine hydrochloride (LiH), an amide-type local anesthetic agent, is commonly used in dermatological procedures. LiH is categorized as a BCS (biopharmaceutics classification system) class III group, which has high solubility and poor permeability. It should be noted that, in this context, LiH is intended as a local anesthetic, so the level of LiH in systemic circulation should be minimized to avoid toxicity and unwanted side effects such as hypotension and bradycardia. This study aimed to formulate and evaluate LiH-loaded dissolving microneedles (DMNs) with different polymer bases. Moreover, an in vitro permeation study using Franz diffusion cells and in vivo study were also performed. LiH-loaded DMNs were prepared using polymer groups of poly(vinyl pyrrolidone) (PVP-K30) and hyaluronic acid (HA). DMNs were created using the micro-molding method with centrifugation. The formulations selected based on the evaluation were F3 (HA 10%) and F5 (PVP-K30 25%). Based on the in vitro permeation study, the amount of drug permeated and deposited in the skin at F3 (HA 10%) was 247.1 ± 41.85 and 98.35 ± 12.86 µg, respectively. On the other hand, the amount of drug permeated and deposited in the skin at F5 (PVP-K30 25%) was 277.7 ± 55.88 and 59.46 ± 9.25 µg, respectively. Our in vivo drug-permeation study showed that only one rat from the PVP-K30 polymer group-with a concentration of 150.32 ng/mL-was detected on rat plasma. Therefore, LiH can be formulated into a DMN and can be deposited in the skin with a safe concentration of the drug permeating into systemic circulation.

Thiolated pectin-chitosan composites: Potential mucoadhesive drug delivery system with selective cytotoxicity towards colorectal cancer.

Mucoadhesive drug delivery systems (DDS) may promote safer chemotherapy for colorectal cancer (CRC) by maximizing local drug distribution and residence time. Carbohydrate polymers, e.g. pectin (P) and chitosan (CS), are potential biomaterials for CRC-targeted DDS due to their gelling ability, mucoadhesive property, colonic digestibility, and anticancer activity. Polymer mucoadhesion is augmentable by thiolation, e.g. pectin to thiolated pectin (TP). Meanwhile, P-CS polyelectrolyte complex has been shown to improve structural stability. Herein, we fabricated, characterized, and evaluated 5-fluorouracil-loaded primary DDS combining TP and CS as a composite (TPCF) through triple crosslinking actions (calcium pectinate, polyelectrolyte complex, disulfide). Combination of these crosslinking yields superior mucoadhesion property relative to single- or dual-crosslinked counterparts, with comparable drug release profile and drug compatibility. PCF and TPCF exhibited targeted cytotoxicity towards HT29 CRC cells with milder cytotoxicity towards HEK293 normal cells. In conclusion, TP-CS composites are promising next-generation mucoadhesive and selectively cytotoxic biomaterials for CRC-targeted DDS.

Keratin-Alginate Sponges Support Healing of Partial-Thickness Burns.

Deep partial-thickness burns damage most of the dermis and can cause severe pain, scarring, and mortality if left untreated. This study serves to evaluate the effectiveness of crosslinked keratin-alginate composite sponges as dermal substitutes for deep partial-thickness burns. Crosslinked keratin-alginate sponges were tested for the ability to support human dermal fibroblasts in vitro and to support the closure and healing of partial-thickness burn wounds in Sus scrofa pigs. Keratin-alginate composite sponges supported the enhanced proliferation of human dermal fibroblasts compared to alginate-only sponges and exhibited decreased contraction in vitro when compared to keratin only sponges. As dermal substitutes in vivo, the sponges supported the expression of keratin 14, alpha-smooth muscle actin, and collagen IV within wound sites, comparable to collagen sponges. Keratin-alginate composite sponges supported the regeneration of basement membranes in the wounds more than in collagen-treated wounds and non-grafted controls, suggesting the subsequent development of pathological scar tissues may be minimized. Results from this study indicate that crosslinked keratin-alginate sponges are suitable alternative dermal substitutes for clinical applications in wound healing and skin regeneration.

Potential of Tamanu (Calophyllum inophyllum) Oil for Atopic Dermatitis Treatment.

Tamanu oil, derived from the nut of Calophyllum inophyllum L., has been traditionally used to treat various skin-related ailments. In recent years, this oil is increasingly gaining popularity as researchers continue to search for novel natural alternative therapies for various skin diseases. There have been a number of in vitro and in vivo studies investigating various skin-active properties of tamanu oil, and it has been proven to have potent anti-inflammatory, antioxidant, antimicrobial, analgesic, and even wound-healing abilities. These properties make tamanu oil an especially interesting candidate for the treatment of atopic dermatitis (AD). This multifaceted disease is marked by the disruption of the skin barrier function, chronic inflammation, and skin microbiome dysbiosis with limited treatment options, which is free from adverse events and inexpensive, making it desperate for a new treatment option. In this review, we examine previous in vitro and in vivo studies on AD-relevant pharmacological properties of tamanu oil in order to evaluate the potential of tamanu oil as a novel treatment option for AD.

Fabrication and characterization of a novel crosslinked human keratin-alginate sponge.

Human hair keratins have been explored for biomedical applications because of their abundance, bioactivity and processability. However, pure keratin templates have poor mechanical properties, which limit their practical relevance. Herein, we described a novel composite sponge, consisting of human hair keratins chemically crosslinked with alginate using 1-ethyl-3-dimethylaminopropyl carbodiimide hydrochloride, with improved mechanical properties. Fourier transform infrared spectroscopy (FTIR) and free amine group quantification using ninhydrin revealed a maximum crosslinking index of 82.1 ± 1.3%. With increasing alginate proportions, the sponges exhibited increased tensile strength, tensile modulus and compression modulus at maximum values of 10.3 ± 1.92 kPa, 219.07 ± 52.39 kPa and 191.48 ± 32.89 kPa, respectively. The crosslinked sponges also demonstrated water vapour transmission rates comparable to commercial wound dressings. Meanwhile, sponges with higher proportions of keratin showed lower water uptake capacities and higher degradation rates by proteinase K, in comparison with sponges with higher proportions of alginate. Higher proportions of keratin on coated two-dimensional surfaces and in three-dimensional sponges resulted in more attachment and improved proliferation of L929 fibroblasts, verifying the bioactive role of keratin in the composites. In addition, subcutaneous implantation of the keratin-alginate sponges into C57BL/6NTac mice over 4 weeks showed no significant immunological reaction and minimal formation of fibrotic capsules. Furthermore, the sponges supported cellular infiltration, neo-tissue formation and vascularization in vivo. These findings demonstrated the feasibility of producing crosslinked human hair keratin-alginate sponges, with tuneable physical and mechanical properties, which are cell compliant in vitro and biocompatible in vivo, suggesting their potential for clinically relevant exploitations. Copyright © 2016 John Wiley & Sons, Ltd.

Modulating Mesenchymal Stem Cell Behavior Using Human Hair Keratin-Coated Surfaces.

Human mesenchymal stem cells (hMSCs) have shown great potential for therapeutic purposes. However, the low frequencies of hMSCs in the body and difficulties in expanding their numbers in vitro have limited their clinical use. In order to develop an alternative strategy for the expansion of hMSCs in vitro, we coated tissue culture polystyrene with keratins extracted from human hair and studied the behavior of cells from 2 donors on these surfaces. The coating resulted in a homogeneous distribution of nanosized keratin globules possessing significant hydrophilicity. Results from cell attachment assays demonstrated that keratin-coated surfaces were able to moderate donor-to-donor variability when compared with noncoated tissue culture polystyrene. STRO-1 expression was either sustained or enhanced on hMSCs cultured on keratin-coated surfaces. This translated into significant increases in the colony-forming efficiencies of both hMSC populations, when the cells were serially passaged. Human hair keratins are abundant and might constitute a feasible replacement for other biomaterials that are of animal origin. In addition, our results suggest that hair keratins may be effective in moderating the microenvironment sufficiently to enrich hMSCs with high colony-forming efficiency ex vivo, for clinical applications.