Mechanisms and kinetics of drug release from lignin-based hydrogels: a review

Lignin-based hydrogels are gaining recognition as promising biomaterials for medical applications, especially in drug delivery. This is due to their biocompatibility, biodegradability, and tunable properties. This review presents an analysis of the mechanisms and kinetics of drug release from lignin-based hydrogels, focusing on their synthesis, functional properties, and applications. It begins by detailing the composition and synthesis methods of lignin-based hydrogels, emphasizing their unique structural features that facilitate controlled drug release. The review also discusses the mechanisms of drug release, including diffusion, swelling, and degradation-controlled processes, and how these mechanisms impact release kinetics. Key factors influencing drug release, such as hydrogel composition, crosslinking density, and environmental conditions (e.g., pH, temperature, and bio-factors), are critically examined. Additionally, the review explores the use of mathematical models, such as the zero-order, first-order, Higuchi, and Korsmeyer-Peppas models, in predicting and optimizing drug release profiles. Summaries of experimental studies, both in vitro and in vivo, demonstrate the potential of lignin-based hydrogels in targeted and controlled drug delivery systems. Despite their potential, challenges such as limited clinical translation and scalability persist. The review concludes by identifying future research directions to address these challenges and further advance the application of lignin-based hydrogels in drug delivery. By integrating insights from recent studies, this review highlights the transformative potential of lignin-based hydrogels in enhancing therapeutic outcomes and advancing biomedical technologies.