This article provides a comprehensive review of chitosan-based hydrogels for transdermal drug delivery. It covers various aspects including the chemical structure of chitosan and its derivatives, crosslinking agents, hydrogel morphology, and drug loading and release behaviors. The review draws on 16 studies sourced from Scopus, focusing on how the composition and structure of hydrogels influence drug release. The chemical structure of chitosan and its derivatives, such as chitosan hydrochloride and quaternary ammonium chitosan, plays a crucial role in determining the mechanical properties and stability of hydrogels. Crosslinking agents, both chemical and physical, affect the hydrogel's strength and transparency as well as its drug release profile. Hydrogel morphology, including its porosity, significantly impacts drug loading capacity and release behavior. Hydrogel-based microneedles show potential in overcoming the limitations of traditional drug administration methods by enhancing skin penetration and drug loading efficiency. Additionally, factors such as swelling ratio, drug loading efficiency, and release behavior are influenced by crosslinking methods, material composition, and environmental conditions. This article concludes that the design and modification of chitosan-based hydrogels can optimize transdermal drug delivery by improving drug release profiles and stability.
Efforts to produce microwave absorber materials that are inexpensive and environmentally friendly have become a means of greening the environment. The breakthrough can be focused on industrial waste and natural materials for functional purposes and how to enhance their performance. We successfully synthesized nickel slag/laterite soil (NS/LS) and nickel slag/iron sand (NS/IS) nanocomposites using a simple mechanical alloying technique, and the electromagnetic (EM) wave absorption capacities of the nanocomposites were measured using a vector network analyzer. The structural properties of the nanocomposites were analyzed by X-ray diffraction spectroscopy, where the results of the analysis showed that NS/IS has the largest crystallite size (15.69 nm) and the highest EM wave absorption performance. The optical properties of the nanocomposites were determined from their Fourier transform infrared spectra using the Kramers-Kronig relation. As determined through a quantitative analysis of the optical properties, the distance between the longitudinal and transversal optical phonon wavenumber positions (Δ(LO - TO) = 65 cm-1) is inversely proportional to the reflection loss. The surface morphologies of the nanocomposites were analyzed by scanning electron microscopy, and the particle diameters were observed by binary image and Gaussian distribution analyses. The nanocomposite surface exhibits a graded-like morphology, which indicates multiple reflections of the EM radiation, consequently reducing the EM interference. The best nanocomposite for an attenuated EM wave achieved a reflection loss of -39.14 dB at 5-8 GHz. A low penetration depth has implications for the electrical charge tuning of the storage and composite magnets. Finally, the EM absorption properties of NS/IS and NS/LS indicate a 2-mm-thick environmentally friendly nanocomposite for EM absorption.