Transdermal Drug Delivery using Nanogels: Methods of Preparation and Evaluation Techniques

Nanogels have emerged as a promising platform for transdermal drug delivery due to their unique physicochemical properties, such as high-water content, tunable size, and responsive behavior. This review highlights the recent advancements in nanogel-based transdermal drug delivery systems, focusing on methods of preparation and evaluation techniques. Various preparation methods, including oil in water (o/w) emulsion solvent diffusion method, inverse (mini) emulsion polymerization technique, membrane emulsification technique, spray drying/cross linking reversible addition-fragmentation chain transfer (RAFT) polymerization, are discussed in detail. Furthermore, critical evaluation parameters such as particle size measurement, drug content, zeta potential, entrapment efficiency, rheological evaluation, SEM analysis, TEM analysis, in vitro drug release, skin irritation studies and skin permeation studies are explored to assess nanogel effectiveness. The ability of nanogels to enhance drug permeation through the skin barrier, provide controlled release, and improve patient compliance underscores their potential in modern therapeutics. This review aims to provide comprehensive insights into the design, development, and evaluation of nanogels for efficient transdermal drug delivery, highlighting future challenges and opportunities in the field.