The objective of this review is to provide an in-depth overview of the current state of research on microneedles for drug delivery, with emphasis on composite systems, particularly those based on hyaluronic acid (HA) and zinc oxide as composite systems. The review discusses the advantages, challenges, and future directions associated with the use of these materials for microneedle-based drug delivery. Hyaluronic acid, which is naturally found in human tissue, has been shown to enhance drug permeation and improve skin hydration, while ZnO has provided high mechanical durability and prevented microbial and bacterial growth. The use of dissolvable microneedles is a viable substitute for traditional drug delivery methods such as oral or intravenous administration. Ongoing research is being conducted to further improve the performance, safety, and effectiveness of microneedles for various drug delivery applications.

This study examines the physicomechanical and special properties of polymer films composed of hyaluronic acid (HA) and zinc oxide (ZnO) nanoparticles that can be used as transdermal patches. Transdermal patches are a popular method of medical and cosmetic procedures in various disciplines, not limited to cosmetology, gynecology, oncology, etc. They have advantages such as convenience and simplicity, the possibility of uniform drug delivery, and a wide range of possible applications. These advantages make transdermal patches an important tool for various areas of medicine. However, most biopolymers used as a polymer matrix do not meet the required physicomechanical properties when creating polymer films for medical purposes. That is why hyaluronic acid with ZnO nanoparticles as a filler was chosen as a polymer base. The work examines the effect of nanoparticle concentration on the physicomechanical and special properties of hyaluronic acid-based polymer films. It has been shown that using 5 wt.% ZnO nanoparticles results in the production of a polymer film based on hyaluronic acid, with optimal mechanical parameters for the balance between the relative elongation and strength of the resulting materials and compliance with the skin texture, which is of critical importance for increasing the long-term effectiveness of the use of the obtained polymer films as a base for creating transdermal patches

Microstructure of composite films composed of polymers and nanoparticles is crucial for understanding the nanoparticles (NPs) dispersion and the role by colloidal stability played in the film formation process. The research aims to create composite films from the combination of hy-aluronic acid (HA) and zinc oxide nanoparticles (ZnO NPs) to produce materials that integrate an-timicrobial properties as a medical application interface. The main problem of composite films involving ZnO NPs is dispersion in polymer matrix which compromises mechanical integrity and structure performance. We discovered key parameters of phase separation influenced by ther-modynamic factors and then observed interfacial compatibility through a nanoscale resolution ZnO NPs dispersion, its adhesion mechanisms and defect distribution. We utilized a pH driven HA/ZnO electrostatic reaction by generating a protonation without any form of chemical change, using citric acid as stabilizing agent and this reverses the Zeta potential of the filler (ZnO NPs) to +25mV , and then we used atomic force microscopy (AFM) to study the microstructure of the films and optical microscope for the morphology. The process also covers surface modification of ZnO through PEGylation. The AFM analysis showed that surface roughness and particle size vary with respect to whether the ZnO nanoparticles were functionalized, unmodified or chelated. The research results will help create HA-based composite films and microneedles with specific nanostructures for wound healing and drug delivery administration.

Polymeric microneedles are introduced as a promising platform for minimally invasive drug delivery and molecular transport control. In the present study, hollow dissolving nanocomposite microneedles based on a mixture of high- and low-molecular-weight hyaluronic acid (HA) in a 40:60 ratio, including zinc oxide nanoparticles (ZnO NPs), have been created and evaluated as hydrated polymer transport matrices. Surface modification of ZnO nanoparticles using citric acid was proposed to improve dispersion by reducing agglomeration of nanoparticles in the polymer matrix. ZnO nanoparticles in concentrations ranging from 1 to 10% (w/w) were used to study the effects of the loading level of nanoparticles on the structure, mechanical response, and controlled diffusion behavior of hydrated polymer matrices. The created nanocomposites exhibited clear hollow structures with tip radius of 18–23 μm, height of 1500 μm, and aspect ratio of 5.7. Nanoscale surface organization and particle dispersion in the polymer matrix were studied by scanning electron microscope (SEM) and atomic force microscope (AFM). Low nanoparticle concentrations were favorable for maintaining high matrix homogeneity, while high concentrations resulted in increased surface roughness and nanoparticle agglomeration. Mechanical compression testing confirmed that hydrated HA/ZnO microneedles were characterized by elastic bending behavior until fracture. Diffusion experiments performed in Franz diffusion cells showed that nanoparticle concentration significantly impacted the cumulative transport and flux of molecules through the hydrated microneedle matrix. Formulations with 5% and 7% ZnO nanoparticles were characterized by a prolonged diffusion behavior attributed to ZnO-induced tortuous transport channels in the polymer matrix. In contrast, formulations with 10% ZnO nanoparticles exhibited accelerated heterogeneous transport due to ZnO-induced changes in structure and morphology. The experimental diffusion data correlated well with the Higuchi kinetic model, and anomalous transport was detected using the Korsmeyer–Peppas model, which indicated a synergistic effect of diffusion and polymer relaxation on molecular transport. As compared to coating and tip-loaded microneedle designs, the obtained HA/ZnO nanocomposite microneedles offered a simple approach for embedding Ciprofloxacin in the hydrated polymer matrix. This was achieved due to the direct creation of microneedles containing dissolved particles.

The objective of this review is to provide a comprehensive overview of the current state of research on micro needles for drug delivery using composite materials on the base of hyaluronic acid and zinc oxide. The review discusses the advantages, challenges, and future directions associated with the use of these materials for micro needle-based drug delivery. Hyaluronic acid which is naturally found in the human tissue has shown to enhance drug permeation and improve skin hydration, while ZnO has provided high mechanical durability and prevent microbial and bacterial growth. The use of dissolvable microneedles is a promising alternative to traditional drug delivery methods such as oral or intravenous administration. Ongoing research is being conducted to further improve the performance, safety, and effectiveness of micro needles for various drug delivery applications.