Focused Review on pH- and Temperature-Responsive Pectin-Based Hydrogels for Drug Delivery and Controlled Release Applications

Stimuli-responsive hydrogels demonstrate an intelligent ability to respond to environmental triggers, such as pH, temperature, etc. Such an ability has been applied to the control release drug delivery system to specific sites with controllable kinetics. Natural macromolecules, especially pectin, have a high potential to develop into stimuli-responsive hydrogels for biomedical applications due to their versatile gelling properties, high biocompatibility, biodegradability, and nontoxicity. Furthermore, the chemical structure of pectin also offers modifications through various chemical reactions to enhance the ability of responding to external triggers under physiological conditions. While pectin has been widely studied in drug delivery, its potential as a smart hydrogel for site-specific, stimuli-responsive drug release remains underexplored. This review highlights recent advancements in pectin modifications to improve its responsiveness to pH and temperature variations, which are crucial for biomedical applications. Additionally, the underlying mechanisms governing these behaviors in pectin-based hydrogels are discussed.