Remote Temperature-Responsive Parafilm Dermal Patch for On-Demand Topical Drug Delivery

Development and characterization of alginate and chitosan hybrid films for dual administration of neomycin and lidocaine

Wound care is frequently hindered by infections, which prevent recovery and adversely affect patients' quality of life. A prevalent example is the presence of bacteria such as Staphylococcus aureus, which can lead to severe inflammation. This study developed and characterized hybrid films composed of alginate and chitosan, incorporating the antimicrobial agent neomycin and the local anesthetic lidocaine, to be applied as a dressing for wound treatment. The research employed an experimental design to identify the optimal formulation, evaluating aspects such as uniformity, cracking, and consistency of the films. After determining the ideal formulation, the films were evaluated: roughness, moisture absorption, swelling, and thickness. Additionally, advanced analytical techniques such as electron microscopy and spectroscopy were employed to provide a comprehensive characterization of the films. The results indicated that the films maintained good chemical stability after incorporating the drugs, effectively absorbed liquids, and exhibited suitable thickness. Biocompatibility was confirmed through hemolysis and antimicrobial activity tests. The films containing both neomycin and lidocaine exhibited good efficacy against S. aureus, highlighting the enhanced bacterial inhibition when both drugs were present. These hybrid films show promise as dressings, possessing antimicrobial, anesthetic, and biocompatible properties, along with the ability to absorb liquids.

Microneedles as a Promising Technology for Disease Monitoring and Drug Delivery: A Review

The delivery of molecules, such as DNA, RNA, peptides, and certain hydrophilic drugs, across the epidermal barrier poses a significant obstacle. Microneedle technology has emerged as a prominent area of focus in biomedical research because of its ability to deliver a wide range of biomolecules, vaccines, medicines, and other substances through the skin. Microneedles (MNs) form microchannels by disrupting the skin's structure, which compromises its barrier function, and facilitating the easy penetration of drugs into the skin. These devices enhance the administration of many therapeutic substances to the skin, enhancing their stability. Transcutaneous delivery of medications using a microneedle patch offers advantages over conventional drug administration methods. Microneedles containing active substances can be stimulated by different internal and external factors to result in the regulated release of the substances. To achieve efficient drug administration to the desired location, it is necessary to consider the design of needles with appropriate optimized characteristics. The choice of materials for developing and manufacturing these devices is vital in determining the pharmacodynamics and pharmacokinetics of drug delivery. This article provides the most recent update and overview of the numerous microneedle systems that utilize different activators to stimulate the release of active components from the microneedles. Further, it discusses the materials utilized for producing microneedles and the design strategies important in managing the release of drugs. An explanation of the commonly employed fabrication techniques in biomedical applications and electronics, particularly for integrated microneedle drug delivery systems, is discussed. To successfully implement microneedle technology in clinical settings, it is essential to comprehensively assess several factors, such as biocompatibility, drug stability, safety, and production cost. Finally, an in-depth review of these criteria and the difficulties and potential future direction of microneedles in delivering drugs and monitoring diseases is explored.

Skin Cancer Treatment with Subcutaneous Delivery of Doxorubicin-Loaded Gelatin Nanoparticles and NIR Activation

Subcutaneous (SC) administration of chemotherapeutics combined with near-infrared (NIR) light activation can effectively target skin tumors by triggering localized drug release and enhancing cytotoxic effects. In this study, we developed NIR-responsive indocyanine green (ICG) and the chemotherapeutic agent doxorubicin (Dox) loaded into gelatin nanoparticles (NPs) for SC delivery in a skin tumor-bearing mouse model. Histological examination (hematoxylin and eosin staining) confirmed the successful delivery and swelling behavior of the Dox/ICG-loaded gelatin NPs at the SC site. In vitro and in vivo experiments demonstrated that NIR activation of the Dox/ICG-loaded gelatin NPs generated significant photothermal heat (48 and 46 °C), leading to targeted drug release and a substantial reduction in skin tumor size (from 15 to 3 mm3). Our findings suggest that this dual-modality approach of SC chemotherapeutic administration and NIR-triggered photothermal therapy can concentrate cytotoxic drugs at the tumor site, offering a promising strategy for improving skin cancer treatment.

Time-Separated Pulse Release-Activation of an Enzyme from Alginate-Polyethylenimine Hydrogels Using Electrochemically Generated Local pH Changes

β-Glucosidase (EC 3.2.1.21) from sweet almond was encapsulated into pH-responsive alginate-polyethylenimine (alginate-PEI) hydrogel. Then, electrochemically controlled cyclic local pH changes resulting from ascorbate oxidation (acidification) and oxygen reduction (basification) were used for the pulsatile release of the enzyme from the composite hydrogel. Activation of the enzyme was controlled by the very same pH changes used for β-glucosidase release, separating these two processes in time. Importantly, the activity of the enzyme, which had not been released yet, was inhibited due to the buffering effect of PEI present in the gel. Thus, only a portion of the released enzyme was activated. Both enzymatic activity and release were monitored by confocal fluorescence microscopy and regular fluorescent spectroscopy. Namely, commercially available very little or nonfluorescent substrate 4-methylumbelliferyl-β-d-glucopyranoside was hydrolyzed by β-glucosidase to produce a highly fluorescent product 4-methylumbelliferone during the activation phase. At the same time, labeling of the enzyme with rhodamine B isothiocyanate was used for release observation. The proposed work represents an interesting smart release-activation system with potential applications in biomedical field.

Using Polymers as Crystal Inhibitors to Prevent the Crystallization of the Rotigotine Patch

This study aimed to enhance the stability of the Rotigotine (ROT) patch using polymers as crystal inhibitors. Three polymers (Poloxamer 188, Soluplus, TPGS) were selected as crystal inhibitors to formulate ROT patches with varying drug loadings (20%, 40%, 60%, and 80%, w/w). SEM and XRD analysis revealed that the Soluplus and Soluplus-TPGS groups with a high concentration (80%, w/w) of ROT could be stored at room temperature for at least 90 days without crystallization. Moreover, the crystallization nucleation time and growth rate were utilized to assess the ability of Poloxamer 188, Soluplus, and TPGS to hinder the formation of ROT crystals and slow down its crystallization rate. Molecular docking results elucidated the intermolecular forces between ROT and different polymers, revealing their mechanisms for crystal inhibition. The ROT-Soluplus-TPGS combination exhibited the lowest binding free energy (-5.3 kcal/mol), indicating the highest binding stability, thereby effectively reducing crystal precipitation. In vitro skin permeation studies demonstrated that ROT patches containing crystal inhibitors exhibited promising transdermal effects. With increasing ROT concentration, the cumulative drug permeation substantially increased, while the lag time was notably reduced. This study offers novel insights for the development of ROT patches.

Nanostructured chitosan-polyphenolic patch for remote NIR-photothermal controlled dermal drug delivery

We describe the synthesis of a nanostructured dermal patch composed of chitosan-tannic acid (CT) that can carry near-infrared (NIR) active Indocyanine green (ICG) dye for performing photothermal heat conversion activity. The NIR-responsive CT-I dermal patch can deliver topical antibiotic drugs (Neomycin). The CT-I and drug-loaded CT-I/N patches have been demonstrated by FTIR, SEM/EDX, TGA, and DSC analysis. The in vitro drug release from the CT-I/N patch are favorable in the dermal environment (pH = 5.5) and significantly increases 25 % more at higher temperatures of 40 to 45 °C. The CT-I/N showed increasing photothermal heat in response to NIR (808 nm) light. The in vivo thermograph demonstrated that the CT-I/N patch can generate >45 °C within 5 min NIR irradiation. As a result, sustained wound healing was shown in H&E (hematoxylin and eosin) staining dermal tissue. Such NIR-active nanostructure film/patch is promising for the future of any sustained on-demand drug delivery system.

Synthesis and Evaluation of Poly(3-hydroxypropyl Ethylene-imine) and Its Blends with Chitosan Forming Novel Elastic Films for Delivery of Haloperidol

This study aimed to develop novel elastic films based on chitosan and poly(3-hydroxypropyl ethyleneimine) or P3HPEI for the rapid delivery of haloperidol. P3HPEI was synthesized using a nucleophilic substitution reaction of linear polyethyleneimine (L-PEI) with 3-bromo-1-propanol. ¹H-NMR and FTIR spectroscopies confirmed the successful conversion of L-PEI to P3HPEI, and the physicochemical properties and cytotoxicity of P3HPEI were investigated. P3HPEI had good solubility in water and was significantly less toxic than the parent L-PEI. It had a low glass transition temperature (T_g = -38.6 °C). Consequently, this new polymer was blended with chitosan to improve mechanical properties, and these materials were used for the rapid delivery of haloperidol. Films were prepared by casting from aqueous solutions and then evaporating the solvent. The miscibility of polymers, mechanical properties of blend films, and drug release profiles from these formulations were investigated. The blends of chitosan and P3HPEI were miscible in the solid state and the inclusion of P3HPEI improved the mechanical properties of the films, producing more elastic materials. A 35:65 (%w/w) blend of chitosan-P3HPEI provided the optimum glass transition temperature for transmucosal drug delivery and so was selected for further investigation with haloperidol, which was chosen as a model hydrophobic drug. Microscopic and X-ray diffractogram (XRD) data indicated that the solubility of the drug in the films was ~1.5%. The inclusion of the hydrophilic polymer P3HPEI allowed rapid drug release within ~30 min, after which films disintegrated, demonstrating that the formulations are suitable for application to mucosal surfaces, such as in buccal drug delivery. Higher release with increasing drug loading allows flexible dosing. Blending P3HPEI with chitosan thus allows the selection of desirable physicochemical and mechanical properties of the films for delivery of haloperidol as a poorly water-soluble drug.