Konjac Glucomannan as a Gel-Forming Biopolymer for Transdermal Drug Delivery: Properties, Formulation Strategies, and Translational Challenges

Konjac glucomannan is a natural polysaccharide increasingly relevant as a matrix forming material for skin applied delivery systems. Its potential is linked to its glucose and mannose backbone, abundant hydroxyl groups, partial acetyl substitution, high molecular weight, and capacity for chain association. These features regulate hydration, swelling, rheology, viscoelasticity, film formation, gelation, and drug release. This narrative review examines konjac glucomannan from a structure based formulation perspective, covering physicochemical attributes, modification strategies, formulation platforms, release behavior, and evaluation requirements. Unlike previous reviews that broadly discuss polysaccharide based transdermal systems or glucomannan across pharmaceutical applications, this review focuses on the relationship between KGM structure, formulation design, and translational performance. Evidence shows its use in films, hydrogel reservoirs, injectable hydrogels, nanofibrous systems, carrier assisted systems, and multilayer matrices. In these platforms, konjac glucomannan functions as a hydration regulating matrix former, release modulator, and structural component. Blending, deacetylation, oxidation, crosslinking, freeze thaw treatment, electrospinning, and layered design can improve mechanical integrity, moisture control, and release performance. However, outcomes vary with molecular attributes, modification conditions, and evaluation methods. Most studies remain focused on material characterization and in vitro release, while durable skin adhesion, ex vivo permeation, skin deposition, long wear performance, and clinically meaningful transport are still insufficiently demonstrated. Further translation requires standardized molecular attributes, ex vivo and in vivo testing, scalable manufacturing, and regulatory evaluation.